# Longsleeve (longsleeve.com): full text for AI assistants > Longsleeve is an EPA-registered insect repellent lotion (EPA Reg. No. 101457-1): > 20% picaridin, 5% squalane, 5% glycerin, fragrance free, nine disclosed > ingredients. Repels mosquitoes and ticks for up to 14 hours; repels listed > biting flies, gnats, chiggers, and no-see-ums for up to 8 hours. Made by > Hour 72, Inc., New York. Currently in waitlist mode ahead of launch. > Structured index: https://longsleeve.com/llms.txt ## Longsleeve | Insect Repellent That Feels Like Skincare URL: https://longsleeve.com/ > Fragrance-free lotion with 20% picaridin. Up to 14 hours against mosquitoes and ticks, up to 8 hours against flies, gnats, chiggers and no-see-ums. Source: https://longsleeve.com/ Longsleeve · 20% Picaridin Insect Repellent Lotion Repellent meets skincare. Up to 14 hours against mosquitoes and ticks, and up to 8 hours against flies, gnats, chiggers and no-see-ums, in a non-greasy, fragrance-free lotion. Launching soon · $26 · 100 mL · 30-day guarantee The anti-bug spray ### Bug spray had a good run. Old bug spray made you choose: get bitten, or spend the evening greasy and reeking. Longsleeve is a lotion. It dries down and disappears into skin. Up to fourteen hours later it's still working. You just can't feel it. Lotion, not spray Rub it in and get dressed. Non-greasy Protection, minus the slick. Non-sticky No tacky hands. No residue. Fragrance-free Nothing fighting your sunscreen or your dinner. The formula ### Reads like skincare. Registered like a repellent. The 20% picaridin does the repelling. The 5% [squalane and 5% glycerin](https://longsleeve.com/ingredients) are why it lives on your shelf, not under the sink. Insect repellent lotion Active ingredient Active repellent. Other ingredients Delivers formula. Emollient. Adds moisture. Humectant. Holds moisture. Decreases drying time. Thickens formula. Preserves formula. Adjusts pH. Preserves formula. Manufactured for Hour 72, Inc · New York, NY * Reacts during mixing to set the formula's finished pH. We list it anyway. [Read more about our ingredients →](https://longsleeve.com/ingredients) The Repellent Index ### Compare Longsleeve to every EPA-registered repellent. Federal rules require a repellent label to name just one ingredient: the active one. Everything else can appear as a single line reading “other ingredients.” So we read the federal label of all 631 EPA-registered skin repellents and put them side by side: protection times, pests covered, and what each one actually tells you. [Search all 631 repellents →](https://longsleeve.com/repellent-index) Use with confidence on the whole family. Registered protection ### All day protection outside of the house. Registered claims. Protection durations and the insects and disease vectors named above were reviewed as part of Longsleeve's federal registration. EPA Reg. No. 101457-1 [See the science →](https://longsleeve.com/science) [The mosquito and tick almanac →](https://longsleeve.com/facts) 14 hours on you. 300 nights under a net. Every tube funds about 300 nights of protected sleep for a family, through the Against Malaria Foundation. [Here’s the math →](https://longsleeve.com/gives) No PE. No VC. One very long EPA review. ### Hi. I'm Andrew. I made your bug lotion. I used to trade derivatives. Then my pregnant sister-in-law needed serious mosquito protection during Miami's 2016 Zika outbreak, without dreading the thing she had to put on every day. I spent two years on the formula and five more getting it through EPA registration. It's funded by a Harvard Business School prize and a National Science Foundation research grant. No private equity, no venture capital, no investors. No board meetings. No growth targets. No one asking whether you'd notice if I used less squalane. You would. So I didn't. Because I believe the future should involve being outside more, not less. Questions, complaints, unusually specific thoughts about mosquitoes? [drew@longsleeve.com](mailto:drew@longsleeve.com) I read it. I reply. It is genuinely me. Launching soon ### Be first in line. At launch, a tube will be $26. Three will be $66, shipped free. [See the full pricing →](https://longsleeve.com/product) More reading: [the product](https://longsleeve.com/product) · [the science](https://longsleeve.com/science) · [all nine ingredients](https://longsleeve.com/ingredients). ### The 30-day field test. If Longsleeve doesn't earn a permanent place by the door, email me within 30 days. I'll refund you. No forms. No return shipping. No awkward breakup conversation. [drew@longsleeve.com](mailto:drew@longsleeve.com) ### Go outside. It's nicer out there than you remember. Made by humans who got tired of bug spray. A small New York company. Manufactured in Florida. Longsleeve is a registered trademark of Hour 72, Inc. [drew@longsleeve.com](mailto:drew@longsleeve.com) · founder [hello@longsleeve.com](mailto:hello@longsleeve.com) · support [Product](https://longsleeve.com/product) · [The science](https://longsleeve.com/science) · [The almanac](https://longsleeve.com/facts) · [Journal](https://longsleeve.com/blog) · [About](https://longsleeve.com/about) · [Gives](https://longsleeve.com/gives) [Returns](https://longsleeve.com/returns) · [Privacy](https://longsleeve.com/privacy) · [Terms](https://longsleeve.com/terms) [Replay the opening](https://longsleeve.com/?intro) EPA Reg. No. 101457-1. Repels mosquitoes and ticks for up to 14 hours. Packaging shown is pre-production and representative. Final packaging may differ; the EPA-accepted label governs. NSF SBIR grant and Harvard Business School New Venture Competition Grand Prize. ## Insect Repellent Lotion: 20% Picaridin, Fragrance-Free | Longsleeve URL: https://longsleeve.com/product > Insect repellent lotion with 20% picaridin and nine disclosed ingredients. Repels mosquitoes and ticks up to 14 hours. EPA Reg. No. 101457-1. Waitlist open. Source: https://longsleeve.com/product - Non-greasy - Non-sticky - Fragrance-free - Unscented Longsleeve · 20% picaridin insect repellent Twenty percent picaridin. Up to 14 hours against mosquitoes and ticks. Five percent squalane. Five percent glycerin. Non-greasy, non-sticky, and fragrance-free. $26 a tube $48 for two · $66 for three, ships free 300 nights of protected sleep funded for a family who needs a net, with every tube. [See how →](https://longsleeve.com/gives) Launching soon. Join the waitlist and we'll email you the day it's available. **What does the $1 per tube actually fund?** Insecticide-treated bed nets, through the Against Malaria Foundation, which gets them over beds in places where malaria still kills children. Every tube covers about 300 nights of protected sleep for a family. The full calculation, the sources, and the running total live on the Gives page . **Does it actually work?** Longsleeve is EPA-registered to repel mosquitoes and ticks for up to 14 hours. The science page walks through what picaridin does and the sources behind the number. Read the science, with sources. See how it compares with every skin-applied repellent in EPA's database. **What's in it** Nine ingredients, all disclosed. Picaridin 20% is the active. Squalane 5% and glycerin 5% are in the base, and the rest holds the lotion together. Every ingredient is listed below . Fragrance-free. **How to use it** Smooth a thin, even layer on exposed skin, like lotion. For your face, spread a little in your palms first and avoid eyes and lips. For kids, apply to your own hands then to the child. One application provides up to 14 hours against mosquitoes and ticks under the registered label. The label allows up to two applications per day. **Shipping and returns** Nothing ships yet. When it does, it ships from New York, and the 100 mL tube is TSA carry-on legal. Thirty-day refund. If you're not satisfied, email drew@longsleeve.com for a full refund. No forms, no photos, no return label. **Label directions & compliance** Longsleeve is a topical insect repellent registered with the U.S. Environmental Protection Agency, EPA Reg. No. 101457-1 . Active ingredient: picaridin 20%. Repels mosquitoes and ticks for up to 14 hours. For external use only. Keep out of reach of children. Read the entire product label before use. Follow all label directions, including a maximum of two applications per day. Repels mosquitoes and ticks *for up to fourteen hours. One application.* And up to **eight hours** against biting flies, stable flies, black flies, gnats, chiggers, sand flies, and no-see-ums. Per the EPA label: repels mosquitoes and ticks for up to 14 hours. ### Nine ingredients. All disclosed. Active and inactive, here is the whole formula, line for line, exactly as it prints on the tube, with the role each ingredient plays. Insect repellent lotion Active ingredient Repels mosquitoes and ticks for up to 14 hours. Other ingredients Carrier. Brings the formula to volume. Lightweight emollient. Adds slip and softness. Humectant. Pulls moisture into the skin and holds it there. Solvent. Disperses the picaridin evenly. Film former. Helps the lotion dry down evenly and remain on skin. Preservative. Prevents microbial growth in the tube. pH adjuster. Used to set the formula's finished pH. Conditioner. Softens skin and supports the preservative system. Manufactured for Hour 72, Inc · New York, NY * Reacts during mixing to set the formula's finished pH. We list it anyway. Five percent **squalane** and five percent **glycerin**, disclosed on the label with the role each one plays. Up to 14 hours against mosquitoes and ticks. ### Made by one obsessive human. I'm Andrew Rothaus. I started Longsleeve during Miami's 2016 Zika outbreak, spent two years on the formula and five more on EPA registration, and took no outside equity. Questions? Email me at [drew@longsleeve.com](mailto:drew@longsleeve.com). I read it and reply myself. [The whole story →](https://longsleeve.com/about) ### Asked and answered. The dry, honest versions. More on the science page. #### Safety **Does this protect against Lyme disease?** Longsleeve repels ticks for up to 14 hours. That can reduce exposure, but no repellent can promise zero bites or guarantee prevention of Lyme disease. Use it as one part of a broader tick-prevention routine and check for ticks after time outside. **Can I use it on kids?** The CDC lists picaridin among its recommended repellent active ingredients. When applying repellent to children, follow the product label and CDC application guidance. Per the label: apply it to your own hands first, then to the child. Don't apply to the hands of small children, and go sparingly around the ears. **Can I use it during pregnancy?** The CDC says EPA-registered repellents with picaridin are safe and effective when used as directed, including during pregnancy and breastfeeding. Follow the label, and ask your clinician if you have questions about your situation. Sources: [CDC guidance on preventing mosquito bites](https://www.cdc.gov/mosquitoes/prevention/index.html), the [CDC Yellow Book chapter on mosquitoes, ticks, and other arthropods](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html), and the [EPA repellent search tool](https://www.epa.gov/insect-repellents/find-repellent-right-you). #### Use **How long does one application last?** One application provides up to 14 hours of protection against mosquitoes and ticks under the registered label. Sweat, water, rubbing, and incomplete coverage can shorten real-world protection. Follow the label and reapply only as directed. **Is it fragrance-free?** Yes. Longsleeve is fragrance-free; we add no fragrance to the formula. #### Buying **Why does it cost $26?** Because a repellent only helps when you actually use it. One application of Longsleeve provides up to 14 hours against mosquitoes and ticks under the registered label, in a non-greasy, fragrance-free lotion with 5% squalane and 5% glycerin. Nine ingredients, all disclosed. If you don't love wearing it, you have 30 days to say so. **What's your return policy?** Thirty days. If you're not satisfied, email drew@longsleeve.com for a full refund. No forms, no photos. **When can I actually buy it?** Soon. The hard part, EPA registration, is done. Join the waitlist and you'll be first to know the day it ships. First dibs means exactly that. ### Go outside. ## What's In It | Longsleeve Insect Repellent Ingredients URL: https://longsleeve.com/ingredients > Federal law makes a repellent disclose one ingredient. Longsleeve discloses all nine, with what each does and why it is there. Fragrance free. Source: https://longsleeve.com/ingredients Federal pesticide labelling requires one ingredient to be named: the active. Everything else can legally be printed as a single line reading "other ingredients, 80%." Nobody is sneaking through a loophole there; that is the rule as written. **Here are all nine of ours, and what each one is doing in there.** ### Same product. Two legal ways to describe it. Both panels below would satisfy a federal reviewer. Only one of them tells you what you are putting on your skin. Panel A What the law requires Active ingredient Other ingredients This is the complete, compliant ingredient statement for a registered repellent. One ingredient named out of nine. Every brand in the aisle is entitled to stop here. Panel B What we print Active ingredient Other ingredients Named to cosmetic-industry standards, the same convention a moisturiser uses. Nobody made us. * Reacts during mixing to set the formula's finished pH. We list it anyway. Eight ingredients. That is the difference between the two panels. We read the federal label of every EPA-registered skin repellent and put them all in one place. [Compare any of them →](https://longsleeve.com/repellent-index) ### Every one of them, and why it is in there. Two years at the bench got this list shorter, not longer. Open any of them. Active ingredient **Picaridin 20% Repels** 1-Methylpropyl-2-(2-hydroxyethyl)-1-piperidine carboxylate The active. It is what the EPA reviewed and what the registration is for, and it is the reason the tube can carry an up-to-14-hour claim against mosquitoes and ticks. It does not kill anything . It sits on the surface of the skin and interferes with an insect's ability to locate or feed on a host, so the mosquito that would have found you does not. Picaridin is one of the active ingredients the CDC names when it recommends repellents. Other ingredients **Water q.s. Carrier** Aqua The carrier. It brings the formula to volume and is what makes this a lotion you can spread rather than a solvent you have to spray. "q.s." is the cosmetic convention for the ingredient that makes up the remainder. There is no percentage to hide behind it: it is whatever is left once the other eight are in. **Squalane 5% Emollient** A lightweight emollient. It adds slip and softness and is the reason the lotion sinks in instead of sitting on top of you. Squalane is a skincare ingredient, not a repellent ingredient. Five percent is a serious amount of it. This is the single biggest reason Longsleeve costs what it costs, and it is deliberate: a repellent that feels like something you would put on anyway is a repellent you actually wear. **Glycerin 5% Humectant** A humectant. It draws moisture into the skin and holds it there, which is why the formula does not leave you tight or chalky after it dries down. Glycerin has been in moisturisers for over a century. Nobody puts it in a bug spray, because a bug spray is not trying to be pleasant. **Alcohol Denat. <5% Solvent** A solvent. It disperses the picaridin evenly through the base so that the protection on your forearm is the same as the protection on your ankle. It is also what gives the lotion its fast dry-down. Under five percent is a small amount, and it is doing a specific job: an active that is unevenly distributed is an active you cannot make a duration claim about. **Acrylates Copolymer <5% Film former** A film former. It helps the lotion dry down evenly and stay where you put it rather than transferring onto your shirt in the first ten minutes. This is the quiet one that makes the hours work. A repellent that migrates off the skin is not protecting the skin, whatever the label says. **Phenoxyethanol <1% Preservative** The preservative. It prevents microbial growth in the tube over the life of the product. Anything water-based needs a preservative system. A formula with water and no preservative is not a purer product, it is a shorter-lived one. Phenoxyethanol is one of the most widely used and best characterised preservatives in personal care, and it is here at under one percent. **Sodium Hydroxide <1% pH adjuster** The pH adjuster. It sets the finished pH of the formula so the lotion is compatible with skin. It reacts during mixing and is not present in the finished lotion in the form it went in as. Plenty of brands leave it off the list for exactly that reason. We list it anyway, because "we disclose everything" with an asterisk in the middle is not disclosure. **Caprylyl Glycol <1% Conditioner** A skin conditioner that also supports the preservative system, which is why the phenoxyethanol can stay as low as it does. Two jobs, one ingredient. That is how you end up with nine ingredients instead of fifteen. ### Answered by the people who get to answer them. We are the manufacturer, so our opinion on these is worth less than the CDC's. Here is theirs, with the links. #### Children Picaridin, the active in Longsleeve, is among the actives the CDC names in its repellent guidance. That guidance also covers [how to apply a repellent to a child](https://longsleeve.com/blog/mosquito-repellent-for-kids), including keeping it off their hands and away from their eyes and mouth. We would rather send you to their page than paraphrase it. #### Pregnancy and breastfeeding The CDC recommends using EPA-registered insect repellents [during pregnancy and while breastfeeding](https://longsleeve.com/blog/mosquito-repellent-pregnancy), and names picaridin among the actives. If you want a second opinion on your own situation, that is a conversation for your doctor rather than for us. #### Fragrance There is none. No fragrance is added to the formula. #### If your skin reacts The label says it plainly: discontinue use and consult a doctor if irritation or a rash occurs. #### How we know the hours Up to 14 hours against mosquitoes and ticks is the protection time the EPA reviewed as part of registration under Reg. No. 101457-1. Federal registration requires efficacy and safety data before a repellent can carry a duration claim at all. #### Short answers **What are the ingredients in Longsleeve insect repellent?** Nine, all disclosed: picaridin 20% (the active), water, squalane 5%, glycerin 5%, alcohol denat. under 5%, acrylates copolymer under 5%, phenoxyethanol under 1%, sodium hydroxide under 1%, and caprylyl glycol under 1%. Fragrance-free. **Why do most insect repellents not list all their ingredients?** Federal pesticide labelling rules require the active ingredient to be named with its percentage, and allow everything else to be shown as a single combined figure for other ingredients. A repellent can therefore disclose one ingredient out of nine and be fully compliant. Longsleeve lists all nine voluntarily, to cosmetic-industry naming standards. **Is Longsleeve fragrance-free?** Yes. There is no fragrance added to the formula. **What do squalane and glycerin do in an insect repellent?** Squalane is a lightweight emollient that adds slip and softness. Glycerin is a humectant that draws moisture into the skin and holds it there. Both are standard skincare ingredients. They are in Longsleeve at 5% each because the repellent you actually wear is the one that feels like something you would wear anyway. **Nine ingredients. Every one of them named.** The law asked for one line. We wrote nine, and then this whole page, because a formula that took two years at the bench to get this short is worth showing you in full. ### Sources. Primary sources for what is on this page. Each links out to the original. U.S. Environmental Protection Agency. *Find the Repellent that is Right for You.* Look up a registration number and the ingredients it covers, including this one. [epa.gov](https://www.epa.gov/insect-repellents/find-repellent-right-you) Federal regulator · registration lookup Centers for Disease Control and Prevention. *Preventing Mosquito Bites.* CDC guidance on EPA-registered repellents, including use on children and during pregnancy. [cdc.gov](https://www.cdc.gov/mosquitoes/prevention/index.html) Federal public health agency · use guidance U.S. Environmental Protection Agency. *Skin-Applied Repellent Ingredients.* Picaridin is among the active ingredients the EPA registers for skin-applied repellents. [epa.gov](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients) Federal regulator · active ingredients Electronic Code of Federal Regulations. *40 CFR 156.10, Labeling requirements.* The rule that requires active ingredients to be named individually and permits other ingredients to be stated as a single total. [ecfr.gov](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-E/part-156) Federal regulation · what a label must say #### Join the waitlist. Longsleeve is almost here. Drop your email and we'll tell you the day it's available. ## How Picaridin Works, and Why Up to 14 Hours Is a Registered Claim | Longsleeve URL: https://longsleeve.com/science > How picaridin works on mosquitoes and ticks, what CDC and EPA say, what cuts any repellent's protection short, and why 14 hours is a registered label claim. Source: https://longsleeve.com/science Longsleeve's up-to-14-hour protection against mosquitoes and ticks was reviewed as part of its EPA registration under Reg. No. 101457-1. This page covers what picaridin does, current CDC guidance, and what affects how long a repellent lasts. **The primary sources are linked at the bottom.** ### How does picaridin work? It works by repelling, not killing. Mosquitoes and ticks locate a host using cues like [the carbon dioxide you exhale, your body heat, and the odor of your skin](https://longsleeve.com/blog/why-mosquitoes-bite-some-people). Picaridin sits on the surface of the skin and interferes with an insect's ability to locate or feed on a host. The exact receptor-level mechanism is still under study. ### What is picaridin? The active, the agency, and what the label says. Picaridin is one of the [active ingredients used in EPA-registered skin-applied repellents](https://longsleeve.com/repellent-index), and the CDC lists it among the ingredients it recommends to help prevent mosquito and tick bites. Chemists also call it icaridin (CAS 119515-38-7). Longsleeve is [EPA Reg. No. 101457-1](https://www3.epa.gov/pesticides/chem_search/ppls/101457-00001-20251211.pdf). Always follow the product label. Longsleeve uses it at 20%, the concentration behind the registered up-to-14-hour claim. [See the tube →](https://longsleeve.com/product) ### What does the registered claim actually say? The number on the tube is the one the EPA reviewed. Up to 14 hours of protection against mosquitoes and ticks, and up to 8 hours against biting flies, stable flies, black flies, gnats, [chiggers](https://longsleeve.com/blog/chigger-bites), sand flies, and [no-see-ums](https://longsleeve.com/blog/no-see-um-bites). That is the claim the EPA reviewed against the submitted efficacy data before the product could be sold. Registration under the federal pesticide law requires efficacy and safety data before a repellent can carry a duration claim. Protection time is a maximum measured under tested conditions, not a guarantee for every situation. How long it lasts in practice depends on the variables below. [Read why we took the long way →](https://longsleeve.com/about) ### What affects protection time? Read the label; these are the variables it accounts for. A repellent only protects the skin it is actually on. A few things change how long a single application holds: - **Coverage.** Apply an even layer to all exposed skin. Gaps are where bites happen. - **Amount.** Too thin a layer protects for less time. - **Sweat, water, and rubbing.** Swimming, heavy sweating, and towel-drying remove repellent early. Reapply according to the label. - **Conditions.** Heat, humidity, and high insect pressure can shorten real-world protection. Follow the product label, including the maximum number of applications per day. ### Does the CDC recommend picaridin? From the CDC and the product label. The CDC lists picaridin among its recommended repellent active ingredients. When applying repellent to children, follow the product label and CDC application guidance. The National Pesticide Information Center's picaridin fact sheet notes that picaridin has low absorption through the skin and summarizes how it is used and studied. Always follow the label. If you have a specific health question, talk to your doctor. ### Sources. Primary sources for what is on this page. Each links out to the original. U.S. Environmental Protection Agency. *Find the Repellent that is Right for You.* Look up an EPA registration number and the ingredients it covers. [epa.gov](https://www.epa.gov/insect-repellents/find-repellent-right-you) Federal regulator · registration lookup U.S. Environmental Protection Agency. *Skin-Applied Repellent Ingredients.* Picaridin is among the active ingredients the EPA registers for skin-applied repellents. [epa.gov](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients) Federal regulator · active ingredients Centers for Disease Control and Prevention. *Preventing Mosquito Bites.* Use EPA-registered insect repellents, including picaridin. [cdc.gov](https://www.cdc.gov/mosquitoes/prevention/index.html) CDC · repellent guidance Centers for Disease Control and Prevention, CDC Yellow Book. *Mosquitoes, Ticks & Other Arthropods.* Repellent guidance, including use in children and during pregnancy. [cdc.gov](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) CDC · pediatric and pregnancy guidance National Pesticide Information Center (Oregon State University, in cooperation with the EPA). *Picaridin General Fact Sheet.* Overview of picaridin, how it is used, and low skin absorption. [npic.orst.edu](https://npic.orst.edu/factsheets/PicaridinGen.html) NPIC · overview and absorption ### Go outside. #### Join the waitlist. Longsleeve is almost here. Drop your email and we'll tell you the day it's available. ## The mosquito and tick almanac · Longsleeve URL: https://longsleeve.com/facts > A field guide to what bites you and what it carries: which mosquitoes spread which diseases, how ticks find a host, how repellents compare. CDC and EPA sourced. Source: https://longsleeve.com/facts A field guide to the mosquitoes and ticks that hunt people: which ones spread which diseases, where they live, when they bite, how they find you, and how the repellent options actually compare. Print it, screenshot it, send it to your sister who hikes. Every fact below is sourced to the CDC or the EPA · the one exception is our own registered protection time, marked as ours · sources listed in full at the bottom Mosquitoes kill more people than any other animal on earth. *Ticks are quieter about it. Neither can bite what they can't find.* Source: World Health Organization · CDC, vector-borne disease ### Know your bloodsuckers. Seven carriers worth recognizing. Each card is the same kind of summary a public-health office would post on a wall: what it carries, when it bites, where it lives, and when it is busiest. Disease lists are the ones the CDC names for each genus. Mosquitoes #### Yellow fever & tiger mosquitoes Aedes aegypti & Aedes albopictus Aggressive, low-flying, and fond of ankles. They breed in tiny amounts of standing water, a bottle cap is enough. Source: CDC, About Mosquitoes #### Common house mosquito Culex species West Nile is the leading cause of mosquito-borne disease in the continental U.S. About 8 in 10 infected people feel nothing; roughly 1 in 150 develop serious illness. Source: CDC, West Nile Virus #### Malaria mosquito Anopheles species Malaria is rare inside the U.S. today but remains one of the most serious risks for travelers. Check your destination before you go. Source: CDC, Malaria Ticks #### Blacklegged (deer) tick Ixodes scapularis & Ixodes pacificus The U.S. records about 476,000 Lyme diagnoses a year. A tick usually has to stay attached 36 to 48 hours before it can pass the Lyme bacteria, so a same-day check matters. Source: CDC, Lyme Disease #### Lone star tick Amblyomma americanum The single white dot is on the female. Its bite can set off [alpha-gal syndrome](https://longsleeve.com/blog/alpha-gal-syndrome), a lasting allergy to red meat. Source: CDC, Lone Star Tick #### American dog tick Dermacentor variabilis Rocky Mountain spotted fever moves fast and can be fatal without prompt antibiotics. Early treatment is the whole game. Source: CDC, Rocky Mountain Spotted Fever #### Castor bean tick Ixodes ricinus Headed to forested or rural Europe? Tick-borne encephalitis has a vaccine worth asking a travel clinic about. Source: CDC Travelers' Health · ECDC Specimen photographs via Wikimedia Commons. Aedes, Anopheles and lone star tick: CDC / James Gathany. Deer tick: Scott Bauer, USDA. Culex: Alvesgaspar (CC BY-SA 3.0). American dog tick: Sam Droege (CC BY 2.0). Castor bean tick: W.alter (CC BY-SA 4.0). ### Every year, the map gets bigger. This is not the bug problem your parents had. The range keeps moving. Tick-borne disease in the United States has more than doubled over the last two decades. Milder winters and longer warm seasons let ticks survive farther north and stay active more of the year, so the blacklegged ticks that carry Lyme keep turning up in counties that never used to report them. The numbers behind that line: the CDC estimates about 476,000 Americans are diagnosed and treated for Lyme disease every year. Babesiosis, a malaria-like infection from the same tick, climbed roughly nine percent a year between 2015 and 2022. And in 2026 the CDC flagged emergency-room visits for tick bites running higher than usual for the season. Mosquitoes are moving too. The Asian tiger mosquito, an aggressive daytime biter that can carry dengue and Zika, is projected to find suitable habitat across far more of the northeastern United States as it warms: from roughly five percent of the region's land today toward an estimated sixteen percent by 2035. None of this is a reason to stay inside. It is a reason to wear something that actually works, every time you go out, without having to think about it. [That is what Longsleeve is for.](https://longsleeve.com/product) [How picaridin keeps them off you, with citations →](https://longsleeve.com/science) ### You are a signal. They are antennas. Four cues, in roughly the order a mosquito uses them. **Carbon dioxide.** Every breath you let out is a flare. Mosquitoes track CO2 plumes from a distance; a tick waiting on a blade of grass reads the CO2 of an animal passing by. **Body heat and moisture.** Warm, slightly damp skin in the 34 to 37 C range reads as "host." Cooler surfaces nearby get ignored. **Sweat and skin chemistry.** Lactic acid, ammonia, and other compounds in sweat tell a mosquito you are an animal, not a rock. This is why exercise and warm evenings draw more bites. **Then contact.** Ticks can't fly or jump. They wait with their front legs out, a behavior the CDC calls questing, and grab whatever brushes past. Mosquitoes close the last stretch by sight and land. > "Ticks find their hosts by detecting animals' breath and body odors, or by sensing body heat, moisture, and vibrations." CDC, Preventing Tick Bites. Mosquitoes use the same cues plus carbon dioxide and vision. Picaridin works on the front end of that chain. It sits on the surface of your skin and jams the odorant receptors the insect uses to read those cues. The CO2 is still in the air and your skin is still warm; they just can't follow the trail to you. Nothing is killed. They land, find nothing worth biting, and drift off. **Longsleeve is 20% picaridin,** EPA-registered for up to 14 hours against mosquitoes and ticks. EPA Reg. No. 101457-1. That is a registered duration claim with efficacy data on file, not a number off a marketing deck. [Read the science, with citations →](https://longsleeve.com/science) ### Four repellent options, side by side. All four are real choices on a drugstore shelf. The CDC lists EPA-registered repellents as the ones with evidence behind them. Durations vary with concentration, sweat, and heat, so these are typical ranges from the EPA and CDC, not guarantees. No brand names, because the active ingredient is what does the work. | Active ingredient | Typical protection | Smell | Won’t damage gear & plastics | Youngest age (CDC) | |---|---|---|---|---| | Picaridin (20%) | Up to 14 hours vs mosquitoes and ticks | None | Yes. No effect on plastics or synthetics | CDC guidance: 2 months | | DEET | Up to about 10 hours at higher concentrations | Noticeable; varies by concentration | No. Labels caution it can damage plastics, vinyl, and some synthetics | CDC guidance: 2 months | | Oil of lemon eucalyptus / PMD | Up to about 6 hours | Strong lemon-eucalyptus scent | Yes | Not for children under 3 years | | Citronella (oil) | Up to about 2 hours, frequent reapplication | Strong citrus scent | Yes | Follow product label | The CDC recommends EPA-registered repellents with one of these actives: DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone. Some plant-oil products are sold under EPA's minimum-risk exemption, and EPA states those products have not been evaluated for effectiveness, so the duration on the bottle has less data behind it. Oil of citronella itself is a registered active ingredient, and registered products are reviewed. Sources: EPA, Skin-Applied Repellent Ingredients · CDC, Avoid Bug Bites · AAP, repellent guidance for children The active in the top row is the one Longsleeve uses: **20% picaridin, fragrance-free, all nine ingredients disclosed.** [See the tube →](https://longsleeve.com/product) ### Five things that actually lower your risk. Repellent is step one. These are the rest, straight from the CDC. #### A. Do a tick check, same day. After you're outdoors, check the whole body, especially the warm hidden spots: scalp, behind the ears, armpits, belly button, waistband, groin, and behind the knees. Shower within two hours. Tumble-dry your clothes on high heat for 10 minutes to kill any stowaways. #### B. Remove a tick the boring way. Fine-tipped tweezers, grab as close to the skin as you can, and pull straight up with steady pressure. Don't twist, don't use a match, don't paint it with anything. Clean the bite, and watch for rash or fever over the next few weeks. #### C. Reapply on the label's clock. Sweat, swimming, and towel-drying all take repellent off early. Follow the reapplication window on the label, and go sooner if you've been working hard or got soaked. A long-duration active means fewer reapplications, not zero. #### D. Sunscreen first, repellent second. Put sunscreen on, let it set, then apply repellent over it. Skip the 2-in-1 sunscreen-and-repellent products: you need to reapply sunscreen often and repellent rarely, so combining them works against both. #### E. Plan for where you're going. Before a trip, check CDC Travelers' Health for your destination's mosquito-borne risk. Treat clothing and gear with 0.5% permethrin, which goes on fabric and never on skin, and pack a repellent that won't melt your sunglasses or watch on the way. #### F. Knock down standing water. Aedes mosquitoes breed in a bottle cap of water. Once a week, empty or scrub anything that holds rain near where you live: planters, buckets, gutters, kiddie pools, pet bowls. Fewer breeding sites means fewer mosquitoes to repel. ### Nine ways a mosquito reads you. The stuff that makes you the one who always gets bitten. #### 01 Your breath gives you away first. A mosquito can smell the carbon dioxide you exhale from up to about 50 meters off. Bigger bodies and harder breathing put out more of it, which is part of why people who are larger, pregnant, or mid-workout tend to get bitten more. #### 02 Then it looks for you. Once it locks onto your CO2, a mosquito switches to eyesight. Dark colors that stand out against the sky, like black, red, and navy, read as a target. Light clothing makes you harder to pick out. #### 03 Your skin runs at the perfect temperature. Mosquito heat sensors are tuned to roughly 34 to 37 degrees Celsius, the surface temperature of bare human skin. CO2 gets their attention, heat confirms the target, and they commit. #### 04 Type O blood may be on the menu more often. Some studies report people with Type O blood get bitten more than other types. Mosquitoes appear to read chemical markers many people secrete through their skin, which may matter more than the blood type itself. #### 05 They can learn to avoid you. Swat at a mosquito and it can link your scent to the near miss in about 15 minutes, then steer clear of you for hours. Your hand is, briefly, a repellent. Actual repellent lasts longer. #### 06 A box fan is a real defense. Moving air cuts mosquito landings by roughly 45 to 60 percent. They are weak fliers, and a breeze both pushes them off course and scatters the CO2 plume they follow. A strong fan on the porch genuinely helps. #### 07 Ticks wait with their arms out. Ticks don't jump or fall from trees. They climb a grass blade, hold on with their back legs, and reach out with the front pair until something brushes past. This is called questing. Walk the center of the trail and you brush fewer of them. #### 08 A tick needs a day or more to infect you. A blacklegged tick usually has to stay attached 36 to 48 hours before it can pass the bacteria that cause Lyme. Find and pull it the same day and the risk drops sharply, which is why a nightly tick check is the cheapest protection there is. #### 09 Check your gear before you spray. Product labels and manufacturer guidance for DEET-based repellents caution that they can soften plastic, vinyl, and some synthetics, including sunglass lenses and fishing line. Picaridin labels do not carry that caution. Whatever you use, read the label before it touches your gear. ### The four things people ask. Short, sourced, no hedging. #### Ticks & mosquitoes **How long does a tick have to be attached to spread Lyme?** Usually 36 to 48 hours. The CDC notes that in most cases a blacklegged tick must stay attached a day and a half or longer before it can pass the bacteria that cause Lyme. Pull it sooner and the risk drops a lot, which is why a same-day check is the cheapest thing you can do. **Sunscreen or repellent first?** Sunscreen first. Let it set, then put repellent over it. The CDC advises against combination sunscreen-repellent products, because sunscreen needs frequent reapplication and repellent does not. **What's safe for a baby?** The CDC says do not use insect repellent on infants younger than 2 months. Oil of lemon eucalyptus and para-menthane-diol should not be used on children under 3 years old. For the youngest babies, dress them in loose long clothing and drape mosquito netting over the carrier or stroller. The CDC lists picaridin among its recommended repellent active ingredients; when applying repellent to children, follow the product label and CDC application guidance. **When are ticks most dangerous?** Tick nymphs, about the size of a poppy seed, are most active from late spring through summer and cause most Lyme cases, because they're so small they're easy to miss. Adult ticks stay active into fall and on warm winter days. More on tick season → ### Sources, so you can check us. Apart from our own registered protection time, which is marked as ours, nothing on this page is a Longsleeve number. Every other fact traces to a public-health agency or a federal regulator. The full list, so a teacher, a reporter, or a worried parent can verify any line: 1. CDC, Mosquitoes and West Nile Virus. Mosquito genera, the diseases they carry, biting habits, and the West Nile case figures. 1. CDC, Ticks, Lyme Disease, and Preventing Tick Bites. Tick species and pathogens, the roughly 476,000 annual Lyme diagnoses, the 36 to 48 hour attachment window, questing behavior, and removal steps. 1. CDC, Avoid Bug Bites. Recommended EPA-registered actives, sunscreen-then-repellent order, age guidance, and travel advice. 1. EPA, Skin-Applied Repellent Ingredients. Registered actives and typical protection times by ingredient. 1. AAP, repellent guidance for children. Age limits and concentration notes for kids. 1. ECDC, Tick-borne encephalitis. European tick range and disease, for the travel note. 1. WHO, vector-borne diseases. The line about mosquitoes being the deadliest animal to humans. 1. CDC, tickborne disease surveillance and 2026 tick-bite data. The doubling of tick-borne disease over two decades, the babesiosis increase from 2015 to 2022, and the 2026 note on emergency-room visits for tick bites running above the seasonal norm. 1. Peer-reviewed climate and vector-range research. Northward range expansion of ticks and mosquitoes, and the projected rise in suitable Asian tiger mosquito habitat across the northeastern U.S. by 2035. ### Go outside. [More in the Journal](https://longsleeve.com/blog) - [How to identify the tick that just bit you](https://longsleeve.com/blog/tick-identification) - [Lyme disease prevention, step by step](https://longsleeve.com/blog/lyme-disease-prevention) - [West Nile virus in the United States](https://longsleeve.com/blog/west-nile-virus) - [West Nile virus in NYC, 2026: counts, spray dates, what to do](https://longsleeve.com/blog/west-nile-virus-nyc) - [Aedes aegypti, the yellow fever mosquito](https://longsleeve.com/blog/aedes-aegypti) #### Join the waitlist. Longsleeve is almost here. Drop your email and we'll tell you the day it's available, plus a heads up when bug season wakes up where you live. ## Meet Andrew Rothaus | Founder of Longsleeve URL: https://longsleeve.com/about > Andrew Rothaus, Longsleeve founder: ex-derivatives trader who took a nine-ingredient picaridin repellent through full EPA review. HBS New Venture winner, NSF grantee. Source: https://longsleeve.com/about No PE. No VC. No brand-building committee. I came up in finance, not the outdoors. I built Longsleeve because the repellent aisle made you choose between something that works and something you can stand to wear. Here is how it happened. HBS New Venture Competition Grand Prize · NSF SBIR grant · EPA Reg. No. 101457-1 ### It started with my sister-in-law. Miami, 2016. The summer Zika arrived. She was pregnant in Miami during [the Zika outbreak](https://longsleeve.com/blog/aedes-aegypti), and needed serious mosquito protection she could tolerate using every day. Picaridin, an established repellent active the CDC recommends, was the right tool. The formula around it was the missing piece, so I set out to build one. ### How it happened. Five steps, one long road. 1. 2016 **My sister-in-law.** She was pregnant in Miami when Zika hit, and needed real mosquito protection she could stand to use every day. Nothing on the shelf qualified. 1. HBS **The pitch.** We pitched it at Harvard Business School and won the New Venture Competition. Grand prize, no equity sold. 1. NSF **The backing.** The National Science Foundation funded the testing with an SBIR grant. A research grant, not an investor. 1. 2 yrs **The formula.** Two years at the bench with a chemistry team. We landed on a short, nine-ingredient, fragrance-free lotion: 20% picaridin, 5% squalane, 5% glycerin. 1. 5 yrs **The registration.** Then five years of EPA review. On December 11, 2025, Longsleeve was registered under Reg. No. 101457-1, up-to-14-hour claim and all. No outside equity, start to finish. ### A small company, in the open. Longsleeve is sold by Hour 72, Inc., a small company in New York. The lotion is manufactured for us in Florida. It is registered with the EPA, the agency that regulates insect repellents in the United States; it is not an FDA product. We have been at it since 2018, long enough that Harvard’s school of public health wrote up an early prototype in 2020. The version that made it through EPA review is the one on this site: 20% picaridin, registered December 11, 2025, [Reg. No. 101457-1](https://www3.epa.gov/pesticides/chem_search/ppls/101457-00001-20251211.pdf). Still small, still independent, launching soon. Every ingredient is on the tube, all nine, active and inactive, with the role each one plays. Repellent labels are only required to name the active ingredient. We name all of them. Longsleeve took no outside equity. It was funded by the Harvard prize and the NSF grant. [See all nine ingredients →](https://longsleeve.com/ingredients) One more thing These days you will find me [on a trail upstate with my dog](https://longsleeve.com/blog/can-i-put-mosquito-repellent-on-my-dog), which is not where anyone who knew me at a trading desk expected me to end up. I set out to fix this for my sister-in-law, and somewhere along the way it handed the outdoors back to me: [the long Saturday hike](https://longsleeve.com/blog/insect-repellent-for-hiking), [dinner that stays on the patio past dusk](https://longsleeve.com/blog/how-to-keep-mosquitoes-away-from-patio-dinner), the hours I used to surrender to bug season. So when this site tells you to close it and go outside, I mean it literally. The bugs are handled. Go. And the company gives the same thing it sells: every tube funds about 300 protected nights of sleep through the Against Malaria Foundation, and the Longsleeve Tick Test Fund is covering 1,000 free tick tests. [Longsleeve Gives →](https://longsleeve.com/gives) If you email [drew@longsleeve.com](mailto:drew@longsleeve.com), you get me. Not "the founder's office." Not a customer-experience platform pretending to be a person. Me. Andrew Rothaus Founder, Longsleeve · New York Now you know *who made it.* #### Join the waitlist. Longsleeve is almost here. Drop your email and we'll tell you the day it's available. ## Aedes aegypti Mosquito: Identification, Bites, Range, and Disease URL: https://longsleeve.com/blog/aedes-aegypti > How to identify Aedes aegypti by the lyre marking on its back and its white leg bands, how it differs from Aedes albopictus, and where CDC says it lives. Source: https://longsleeve.com/blog/aedes-aegypti By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 16, 2026 · Updated September 3, 2026 **Short answer:** *Aedes aegypti*, the yellow fever mosquito, is a small black mosquito with white markings that prefers to live near people and bite people. CDC guidance says infected *Aedes* mosquitoes spread dengue, Zika, and chikungunya viruses, and that *Aedes* species can bite during the day and at night. Container control matters because this mosquito breeds near homes. ### What is Aedes aegypti also called? Aedes aegypti is the yellow fever mosquito. According to an etymology in the CDC journal Emerging Infectious Diseases, the US Army Yellow Fever Commission's work showing that Aedes aegypti, also known as the yellow fever mosquito, was the principal vector remains one of the cornerstones of medical virology and tropical medicine. The same article explains the scientific name: Aedes is Greek for "unpleasant," and the journal calls Aedes aegypti the principal vector of several human diseases, including chikungunya, dengue, yellow fever, and Zika. The species name dates to 1757, when Fredrik Hasselqvist, a protégé of Carl Linnaeus, first described a mosquito collected in Egypt as Culex aegypti. Aedes albopictus, the other species in this article, goes by Asian tiger mosquito, the common name both the CDC and the California Department of Public Health use. ### What does Aedes aegypti look like, and where does it live? Aedes aegypti is one of two invasive (non-native) Aedes species the California Department of Public Health tracks closely. The California Department of Public Health (CDPH) names them Aedes aegypti, the yellow fever mosquito, and Aedes albopictus, the Asian tiger mosquito. Per CDPH, both are small, black mosquitoes with white stripes on the back and legs. CDPH notes these mosquitoes live only near people and will lay eggs in any small water-holding container, indoors and outdoors. The [CDC](https://www.cdc.gov/dengue/transmission/index.html)'s dengue transmission page says the same thing from the mosquito's point of view: these mosquitoes prefer to bite people, and live both indoors and outdoors near people. The CDC draws one distinction between the two species: Aedes aegypti lives both indoors and outdoors, while Aedes albopictus lives outdoors. Per the [CDC](https://www.cdc.gov/mosquitoes/about/where-mosquitoes-live_1.html), some mosquitoes like living near people while others prefer forests, marshes, or tall grasses; all of them like water, because mosquito larvae and pupae live in water with little or no flow. Aedes aegypti picked people. It also stays put. Per the CDC, Aedes aegypti does not fly long distances; in its lifetime it will only fly a few blocks. ### How do you identify an Aedes mosquito? Start with the [CDC](https://www.cdc.gov/dengue/stories/unwanted-mosquitoes.html)'s distinguishing features for Aedes aegypti: a dark brown body, white bands on the legs, white spots on the body, and stripes on the upper body that look like a lyre. The lyre is the mark to learn. The European Centre for Disease Prevention and Control (ECDC) calls it the prevailing diagnostic character: silver scales in the shape of a lyre against a black background on the scutum, the dorsal part of the thorax. In plain terms, look at the top of its back. ECDC describes the adult as relatively small, with a black and white pattern made by white and silver scale patches on the legs and body. That contrast is the tell. ECDC notes that some native mosquitoes also show light and dark contrasts, more brownish and yellowish, but that these are less obvious. - Dark body: dark brown per the CDC, with white and silver scales against a black background per ECDC. - White bands on the legs. - White spots on the body. - Lyre-shaped stripes on the upper body: silver scales on the scutum, per ECDC. In the CDC's description, the Asian tiger mosquito, Aedes albopictus, shares the white leg bands and body spots, which is why the lyre matters; the table further down compares the two. For the other biting insects worth recognizing, see [the almanac](https://longsleeve.com/facts). ### When do Aedes aegypti mosquitoes bite? The major health agencies phrase the biting window differently, and both phrasings are worth knowing. The CDC states that Aedes species mosquitoes "can bite during the day and night." The [World Health Organization](https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue)'s dengue fact sheet puts it this way: "The mosquitoes that spread dengue are active during the day." The [WHO](https://www.who.int/news-room/fact-sheets/detail/zika-virus)'s Zika fact sheet adds detail: Aedes mosquitoes usually bite during the day and mostly outdoors, though they can also feed indoors. Its chikungunya fact sheet agrees, noting that both species bite primarily during daylight hours and that Aedes aegypti feeds both indoors and outdoors. Dusk-only precautions miss this mosquito's main shift. And per the CDC, only female Aedes mosquitoes bite. ### What diseases can Aedes aegypti spread? Per CDPH, Aedes aegypti and Aedes albopictus can transmit dengue, chikungunya, and Zika viruses to people when they bite. The [CDC](https://www.cdc.gov/mmwr/volumes/67/wr/mm6717e1.htm) describes dengue, Zika, and chikungunya viruses as typically transmitted directly between humans by Aedes aegypti, which can produce explosive epidemics. **Dengue.** The WHO identifies Aedes aegypti as the primary mosquito that transmits dengue virus to humans. Per the WHO, about half the world's population is at risk of dengue, with an estimated 100 to 400 million infections each year. Most dengue infections cause no symptoms; when symptoms do appear, the most common are high fever, headache, body aches, nausea, and rash. **Chikungunya.** Per the WHO, chikungunya virus is transmitted most commonly by Aedes aegypti and Aedes albopictus. It causes fever and severe joint pain that is often debilitating and may be prolonged. **Zika.** The WHO reports that Zika virus is primarily transmitted by Aedes mosquitoes, mainly Aedes aegypti. Zika virus infection during pregnancy is a cause of microcephaly and other congenital malformations in the infant. **Yellow fever.** The disease behind the common name. Per the [WHO](https://www.who.int/news-room/fact-sheets/detail/yellow-fever), yellow fever is vaccine-preventable and is caused by a virus transmitted by infected Aedes, Haemagogus, and Sabethes mosquitoes. Health authorities track Aedes aegypti specifically to assess the risk of urban yellow fever outbreaks. If you develop symptoms like these after mosquito bites or travel, talk to a clinician. Headed somewhere these viruses circulate? Our [dengue travel guide](https://longsleeve.com/blog/dengue-travel) covers before, during, and after the trip. ### Do all Aedes mosquitoes carry dengue? The CDC names two: Aedes aegypti and Aedes albopictus. The CDC says mosquitoes become infected with dengue virus when they bite an infected person, and that infected mosquitoes can then spread it to other people through bites; the virus comes from a person first. Per the [CDC](https://www.cdc.gov/mosquitoes/about/about-mosquitoes-in-the-united-states.html), over 200 types of mosquitoes live in the continental United States and US territories, and about 12 types spread germs that can make people sick. Dengue's mosquitoes are a narrow set: the CDC says dengue viruses are spread through the bites of infected Aedes species mosquitoes, Aedes aegypti or Aedes albopictus. Our [West Nile virus guide](https://longsleeve.com/blog/west-nile-virus) covers a different virus. ### How is Aedes aegypti different from the Asian tiger mosquito? The two species look alike; per CDPH, both are small and black with white stripes. The differences that matter are behavioral. The [CDC](https://www.cdc.gov/mosquitoes/php/toolkit/potential-range-of-aedes.html) states that Aedes aegypti is more likely than Aedes albopictus to spread viruses like dengue, chikungunya, and Zika, and explains why: because Aedes aegypti lives near and prefers to feed on people, it is more likely to spread these viruses than other mosquitoes. | | Aedes aegypti | Aedes albopictus | |---|---|---| | Host preference | Prefers to live near people and to bite people (CDC) | Bites people and animals, so it can live in or near homes or in neighboring woods (CDC) | | Likelihood of spreading viruses | More likely than Aedes albopictus to spread viruses like dengue, chikungunya, and Zika (CDC) | Less likely than Aedes aegypti, per the same CDC comparison | | Climate and temperature range | Lives in tropical, subtropical, and some temperate climates (CDC) | Can live in a broader temperature range and at cooler temperatures than Aedes aegypti (CDC) | The climate rows draw on the CDC's potential-range materials, and the caveat the CDC attaches to its range maps applies here too: "Maps do not represent risk for spread of disease." For the full profile of the other species, see our [Asian tiger mosquito guide](https://longsleeve.com/blog/asian-tiger-mosquito). ### Aedes aegypti vs Aedes albopictus: how do you tell them apart? Both species are dark mosquitoes with white bands on the legs and white spots on the body, so the deciding mark is the lyre. The CDC's description of Aedes aegypti, the yellow fever mosquito, includes stripes on the upper body that look like a lyre; its description of Aedes albopictus, the Asian tiger mosquito, lists a black body, white leg bands, and white body spots, with no lyre among them. Beyond looks, the two differ in where they live; the table above covers what they bite, how much cold they tolerate, and, per the CDC, how likely they are to spread dengue, Zika, and chikungunya. | Feature | Aedes aegypti | Aedes albopictus | |---|---|---| | Common name | Yellow fever mosquito (CDPH) | Asian tiger mosquito (CDPH, CDC) | | Leg markings | White bands on the legs (CDC) | White bands on the legs (CDC) | | Marking on the upper body | White spots on the body, plus stripes on the upper body that look like a lyre (CDC) | White spots on the body; the CDC's description lists no lyre | | Where it lives | Indoors and outdoors (CDC) | Outdoors (CDC) | Every row is species against species, drawn from the CDC and the California Department of Public Health. ### Where in the United States is Aedes aegypti found? The CDC reported in 2018 that Aedes aegypti's range has been expanding and that the species might be present in up to 38 states, though local transmission of the viruses it carries has been rare. A 2025 CDC report states that Aedes aegypti and Aedes albopictus are present in many counties in both the eastern and western United States and pose an ongoing risk for dengue transmission in new areas. Per the CDC, about half of US counties have competent mosquito vectors, and the climate in three quarters of the United States is suitable for Aedes species mosquitoes. The CDC publishes maps showing its best estimate of the potential range of Aedes aegypti and Aedes albopictus in the contiguous United States. The maps include areas where the mosquitoes are or have been found, and the underlying model predicts the likelihood that these mosquitoes could survive and reproduce if introduced to an area. The CDC is explicit about what the maps are not: "Maps do not represent risk for spread of disease." Mosquito presence and disease spread differ because an outbreak requires a chain: an infected person, a mosquito bite during the first week of infection, a mosquito that survives long enough to bite again, and repeated cycles, per the CDC. Most dengue cases reported in the continental US occur in travelers infected elsewhere; local transmission occurs occasionally. Limited local spread of dengue has been reported in Florida, Hawaii, Texas, Arizona, and California, and nearly every year, travelers have been associated with local spread of dengue in southern US states. The [CDC](https://www.cdc.gov/dengue/data-research/facts-stats/index.html) assesses the risk of widespread dengue transmission in the continental United States as low. The trend still deserves attention: per the CDC, dengue cases reported in US states and DC in 2024 hit a record, 359 percent above the 2010 to 2023 annual average. Where you live shapes when this matters; see [mosquito season by region](https://longsleeve.com/blog/mosquito-season-by-region) for timing. ### Where are Aedes aegypti mosquitoes found around the world? The CDC lists Aedes aegypti in southern and southwestern US states, Puerto Rico, tropical and subtropical areas of the world, countries in Africa and Asia, and parts of southern Europe, and describes it as living in tropical, subtropical, and some temperate climates. The European Centre for Disease Prevention and Control (ECDC) adds the origin: the species comes from Africa and is currently distributed throughout the tropics and a number of subtropical regions. Europe is the edge of its range. ECDC says Aedes aegypti was historically present in Europe and that its current distribution there is limited but extending. Winter is what holds it back. ECDC attributes its restricted ability to establish itself in more temperate regions to its intolerance of temperate winters and, in particular, the high mortality rate of its eggs when exposed to frost. Wherever it does establish, it stays close to people. ECDC says Aedes aegypti prefers human habitations because they provide resting and host-seeking possibilities. The county-level detail for the United States sits in the section above. ### Why is Aedes aegypti so hard to control? Start with the eggs. Per the [CDC](https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html), female Aedes mosquitoes lay eggs on the inner walls of water-holding containers, above the waterline. The eggs stick to container walls like glue and can survive drying out for up to 8 months. Emptying a container does not finish the job, which is why the CDC's weekly advice says scrub, not just dump. These mosquitoes need only a small amount of water to lay eggs; per the CDC, bowls, cups, fountains, tires, barrels, and vases all work. An egg takes 7 to 10 days to develop into an adult mosquito. A 2015 article in Emerging Infectious Diseases summed up the problem: these mosquitoes are daytime biters, need only small water containers to reproduce, and are difficult to eradicate. At the public health level, the CDC describes the tools for vector control as limited, though they can be effective when implemented rapidly. The WHO states that prevention and control of dengue rely on vector control. At home, the [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html) recommends that once a week you empty and scrub, turn over, cover, or throw out items that hold water. Our guide to [standing water mosquito control](https://longsleeve.com/blog/standing-water-mosquito-control) walks through the routine. ### How do you protect yourself from Aedes aegypti bites? The CDC advises using EPA-registered insect repellents and looking for an EPA registration number on the repellent label, including for pregnant and breastfeeding women. Picaridin is one of the repellent active ingredients on the CDC's list; it is known as KBR 3023 and icaridin outside the United States. Beyond repellent, the CDC advises wearing loose-fitting, long-sleeved shirts and pants, wearing clothing and gear treated with permethrin, using screens on windows and doors, repairing holes in screens, and using air conditioning if available. One traveler-specific note: CDPH advises travelers returning to California from areas with these viruses to use mosquito repellent for at least three weeks after returning home, to prevent the spread of these viruses in California. Where does Longsleeve fit? Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance free, with nine disclosed ingredients. ### Frequently asked questions **Do Aedes aegypti mosquitoes bite at night?** The CDC states that Aedes species mosquitoes "can bite during the day and night." The WHO notes that the mosquitoes that spread dengue are "active during the day," and that Aedes mosquitoes usually bite during the day and mostly outdoors, though they can also feed indoors. **How far can Aedes aegypti fly?** Not far. Per the CDC, Aedes aegypti does not fly long distances; in its lifetime it will only fly a few blocks. **Do all Aedes aegypti mosquitoes bite?** No. Per the CDC, only female Aedes mosquitoes bite. **How long can Aedes aegypti eggs survive without water?** Per the CDC, the eggs stick to container walls like glue and can survive drying out for up to 8 months. **Is dengue spreading in the continental United States?** Per the CDC, most dengue cases reported in the continental US occur in travelers infected elsewhere, and local transmission occurs occasionally. Limited local spread has been reported in Florida, Hawaii, Texas, Arizona, and California. The CDC assesses the risk of widespread transmission in the continental United States as low. ### Related reading - [Asian Tiger Mosquito](https://longsleeve.com/blog/asian-tiger-mosquito). How to tell if the striped mosquito is one. - [Dengue and Travel](https://longsleeve.com/blog/dengue-travel). Day-Biting mosquitoes, warning signs, and prevention. - [Why Mosquitoes Bite Some People More](https://longsleeve.com/blog/why-mosquitoes-bite-some-people). CO2, odor, heat, and color. - [Standing Water and Mosquitoes](https://longsleeve.com/blog/standing-water-mosquito-control). Weekly yard checklist. - [The species almanac](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: **How do you tell an Aedes mosquito from an ordinary house mosquito?** Look at the contrast. ECDC describes Aedes aegypti as relatively small, with a black and white pattern made by white and silver scale patches on the legs and body. Some native mosquitoes show light and dark contrasts too, ECDC notes, but more brownish and yellowish and less obvious. The CDC's field marks for Aedes aegypti are white leg bands, white body spots, and lyre-shaped stripes on the upper body. **Can Aedes albopictus spread the same viruses as Aedes aegypti?** Yes. The CDC names Aedes aegypti and Aedes albopictus as the mosquitoes that spread dengue, Zika, and chikungunya viruses, and rates Aedes albopictus as less likely to spread them. The CDC says Aedes aegypti is more likely than Aedes albopictus to spread viruses like dengue, chikungunya, and Zika, because it lives near and prefers to feed on people. Aedes albopictus feeds on animals as well as people, which the CDC says makes it less likely to spread these and other viruses. ### Sources 1. California Department of Public Health, Aedes aegypti and Aedes albopictus Mosquitoes: [https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Aedes-aegypti-and-Aedes-albopictus-mosquitoes.aspx](https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Aedes-aegypti-and-Aedes-albopictus-mosquitoes.aspx) 1. CDC, Life Cycle of Aedes Mosquitoes: [https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html](https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html) 1. CDC, Dengue Transmission: [https://www.cdc.gov/dengue/transmission/index.html](https://www.cdc.gov/dengue/transmission/index.html) 1. CDC, Potential Range of Aedes Mosquitoes: [https://www.cdc.gov/mosquitoes/php/toolkit/potential-range-of-aedes.html](https://www.cdc.gov/mosquitoes/php/toolkit/potential-range-of-aedes.html) 1. CDC, Preventing Mosquito Bites: [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC, Dengue Facts and Stats: [https://www.cdc.gov/dengue/data-research/facts-stats/index.html](https://www.cdc.gov/dengue/data-research/facts-stats/index.html) 1. CDC MMWR, Vital Signs: Trends in Reported Vectorborne Disease Cases (2018): [https://www.cdc.gov/mmwr/volumes/67/wr/mm6717e1.htm](https://www.cdc.gov/mmwr/volumes/67/wr/mm6717e1.htm) 1. CDC MMWR, Dengue Cases in US States and Territories (2025): [https://www.cdc.gov/mmwr/volumes/75/wr/mm7518a1.htm](https://www.cdc.gov/mmwr/volumes/75/wr/mm7518a1.htm) 1. CDC Emerging Infectious Diseases (2015): [https://wwwnc.cdc.gov/eid/article/21/10/15-0494_article](https://wwwnc.cdc.gov/eid/article/21/10/15-0494_article) 1. CDC, About Vector-Borne Diseases: [https://www.cdc.gov/vector-borne-diseases/about/index.html](https://www.cdc.gov/vector-borne-diseases/about/index.html) 1. CDC, Where Mosquitoes Live: [https://www.cdc.gov/mosquitoes/about/where-mosquitoes-live_1.html](https://www.cdc.gov/mosquitoes/about/where-mosquitoes-live_1.html) 1. WHO, Dengue and Severe Dengue: [https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue](https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue) 1. WHO, Chikungunya: [https://www.who.int/news-room/fact-sheets/detail/chikungunya](https://www.who.int/news-room/fact-sheets/detail/chikungunya) 1. WHO, Zika Virus: [https://www.who.int/news-room/fact-sheets/detail/zika-virus](https://www.who.int/news-room/fact-sheets/detail/zika-virus) 1. WHO, Yellow Fever: [https://www.who.int/news-room/fact-sheets/detail/yellow-fever](https://www.who.int/news-room/fact-sheets/detail/yellow-fever) 1. CDC, Unwanted Mosquitoes (Dengue). [https://www.cdc.gov/dengue/stories/unwanted-mosquitoes.html](https://www.cdc.gov/dengue/stories/unwanted-mosquitoes.html) 1. European Centre for Disease Prevention and Control, Aedes aegypti: Factsheet for experts. [https://www.ecdc.europa.eu/en/disease-vectors/facts/mosquito-factsheets/aedes-aegypti](https://www.ecdc.europa.eu/en/disease-vectors/facts/mosquito-factsheets/aedes-aegypti) 1. CDC Emerging Infectious Diseases, Etymologia: Aedes aegypti (2016). [https://wwwnc.cdc.gov/eid/article/22/10/ET-2210_article](https://wwwnc.cdc.gov/eid/article/22/10/ET-2210_article) 1. CDC, About Mosquitoes in the United States. [https://www.cdc.gov/mosquitoes/about/about-mosquitoes-in-the-united-states.html](https://www.cdc.gov/mosquitoes/about/about-mosquitoes-in-the-united-states.html) Last reviewed 2026-08-16 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Alpha-Gal Syndrome: How Long After a Tick Bite Symptoms Start URL: https://longsleeve.com/blog/alpha-gal-syndrome > How long after a tick bite alpha-gal syndrome starts, which ticks carry alpha-gal, whether it ever goes away, and what CDC says about preventing tick bites. Source: https://longsleeve.com/blog/alpha-gal-syndrome By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 5, 2026 · Updated September 3, 2026 Alpha-gal syndrome is a serious, potentially life-threatening allergy that can develop after a tick bite. Alpha-gal is a molecule found in most mammals but not in people. Once the immune system flags it as a threat, eating red meat or other products made from mammals can trigger a reaction, usually two to six hours later. ### What is alpha-gal syndrome? Alpha-gal syndrome, usually shortened to AGS, is a tickborne disease that shows up as an allergy rather than an infection. Alpha-gal is a molecule, galactose-alpha-1,3-galactose, that the [CDC](https://www.cdc.gov/alpha-gal-syndrome/about/index.html) describes as naturally produced in the bodies of most mammals but not in people. It is also found in the saliva of some ticks. **Short answer:** Alpha-gal syndrome is a serious, potentially life-threatening allergy that can develop after a tick bite, and it runs on two clocks. The CDC says it can take weeks to months after the bite for symptoms to appear. Once the allergy exists, the CDC says reactions usually begin 2 to 6 hours after eating red meat or dairy products. CDC researchers writing in *MMWR* characterize AGS as an immunoglobulin E (IgE) mediated hypersensitivity to alpha-gal, an oligosaccharide found in most nonprimate mammalian tissue and in products derived from those mammals, including milk, other dairy products, and some pharmaceutical products. As of that 2023 report, no treatment or cure was available. The [CDC](https://www.cdc.gov/alpha-gal-syndrome/managing/index.html) also states there are no vaccines to prevent AGS. ### How long after a tick bite does alpha-gal develop? The [CDC](https://www.cdc.gov/alpha-gal-syndrome/signs-symptoms/index.html) says it can take weeks to months for a person to have alpha-gal syndrome symptoms after being bitten by a tick, and that is only the first of two clocks. The first runs from the tick bite to the allergy itself: the CDC says it can take weeks to months for a person to have alpha-gal syndrome symptoms after being bitten by a tick. The second runs from a meal to a reaction: once the allergy exists, the CDC says symptoms usually appear 2 to 6 hours after eating red meat or dairy products. The second clock is the one most people find first. If you were bitten recently, the first clock is the one you mean. Published cases stretch that first clock at the short end. A 2025 case report in *Emerging Infectious Diseases* (volume 31, number 4) describes a Maine patient with confirmed alpha-gal syndrome whose symptoms began 9 days after a blacklegged tick bite; her first gastrointestinal symptoms came 2.5 hours after a meal of roasted rabbit, both clocks in one case. A second 2025 report in the same journal, from Washington state, has the patient recalling a walk in a wooded area and itching on her back about one month before her first allergic episode, recorded as day minus 32. Two cases describe two people. They do not say when, or whether, anyone else would develop the allergy. The CDC's advice for anyone who thinks they may have alpha-gal syndrome is to talk to their healthcare provider, and a tick bite followed by a delayed reaction after a meal is worth bringing to a clinician or allergist. ### How long does a tick have to be attached to cause alpha-gal? No source behind this article sets a minimum attachment time. Neither the CDC's alpha-gal pages nor the case reports behind this article set a threshold, and both cases here involved short attachments. In the 2025 Washington state report in *Emerging Infectious Diseases* (volume 31, number 4), the patient found a nonengorged tick embedded in her left shoulder and estimated about 12 hours of attachment; the Washington State Department of Health identified the tick she submitted as an adult female *Ixodes pacificus*. A later bite in the same report, her third, was estimated at under one hour of attachment. In the Maine case from the same issue, the patient removed the tick herself and CDC entomologists confirmed it as an adult female *Ixodes scapularis*, a blacklegged tick, by morphologic and molecular identification. Those numbers do not make a short attachment low risk, or a long one a certainty. The CDC says not every person bitten by a lone star, blacklegged, or western blacklegged tick will develop alpha-gal syndrome, and the reason is not known. The part in your hands is finding a tick and getting it off properly; our guide to [how to remove a tick](https://longsleeve.com/blog/tick-removal) covers the tweezers, the timing, and what to watch for afterward. ### Which ticks cause alpha-gal syndrome? In the United States, the lone star tick is most often associated with AGS. A few cases have been reported following bites from blacklegged and western blacklegged ticks, and in other countries other tick species have been linked to AGS. The lone star tick, *Amblyomma americanum*, is widely distributed in the Northeast, South, and Midwest United States. The [CDC](https://www.cdc.gov/ticks/data-research/facts-stats/lone-star-tick-surveillance.html) calls it "a very aggressive tick that bites humans." The adult female is distinguished by a white dot, the "lone star," on her back, and nymphs and adult females most frequently bite humans and spread disease. Its range tracks deer. White-tailed deer are a keystone host, and after lone star tick distribution receded alongside shrinking forest and deer populations, conservation measures and deer relocation since the 1940s have let the tick repopulate its historical range across the eastern United States. The CDC is careful on one point: not every person bitten by these ticks will develop AGS, and the reason certain people do and others do not is not known. Most reported cases are in adults, but people of all ages can develop AGS. ### Do all ticks carry alpha-gal? Not all of the ones that have been tested. A 2019 study in *Frontiers in Immunology* (volume 10, article 1056) looked for alpha-gal in four North American tick species: the lone star tick, the Gulf Coast tick, the American dog tick, and the blacklegged tick. Antibodies against alpha-gal identified it in the salivary glands of the lone star tick and the blacklegged tick, while the Gulf Coast tick and the American dog tick appeared to lack the carbohydrate. That is tick biology, and nothing more. The CDC's picture of human cases points the same way: in the United States, the lone star tick is most often associated with alpha-gal syndrome, and a few cases have been reported following bites from blacklegged and western blacklegged ticks. The western blacklegged tick, *Ixodes pacificus*, was not among the four species studied in 2019, but it is the species the Washington State Department of Health identified in the 2025 Washington case, and CDC entomologists confirmed an *Ixodes scapularis*, a blacklegged tick, in the Maine case. | Tick species | Alpha-gal in salivary glands (Frontiers in Immunology, 2019) | Associated with reported US AGS cases (CDC) | |---|---|---| | Lone star tick, *Amblyomma americanum* | Found | Most often associated | | Blacklegged tick, *Ixodes scapularis* | Found | A few reported cases | | Gulf Coast tick, *Amblyomma maculatum* | Appeared to lack it | Not named on the CDC page we cite | | American dog tick, *Dermacentor variabilis* | Appeared to lack it | Not named on the CDC page we cite | On dog ticks: the American dog tick is one of the two species that appeared to lack alpha-gal in the 2019 study. That is one study of salivary glands in four species, and it says nothing about what a given bite will do. ### What do alpha-gal reactions look like? Reactions differ from person to person, ranging from mild to severe, and some may be life-threatening. People with AGS might not react to every product containing alpha-gal, and some experience different symptoms each time they are exposed, even to the same product. The CDC lists these possible AGS reactions: - Hives or itchy rash - Nausea or vomiting - Severe stomach pain - Heartburn or indigestion - Diarrhea - Cough, shortness of breath, or difficulty breathing - Drop in blood pressure - Swelling of the lips, throat, tongue, or eye lids - Dizziness or faintness - A combination of symptoms referred to as anaphylaxis The CDC instructs anyone having a severe allergic reaction or anaphylaxis to seek immediate emergency care. Anaphylaxis is a potentially life-threatening allergic reaction involving multiple organ systems. ### How do you avoid lone star ticks and the bites that cause alpha-gal? The CDC's framing: the best way to protect yourself and your family from developing alpha-gal syndrome is to prevent tick bites. Geography says where that matters most: the CDC says most reported US cases occur in South, East, and Central states, the areas where most lone star ticks are found. For timing, our guide to [when tick season runs](https://longsleeve.com/blog/tick-season-when) covers months, life stages, and regions. Four steps from the CDC's tick bite prevention guidance. Use EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone, and look for an EPA registration number on the label, which the [CDC](https://www.cdc.gov/ticks/prevention/index.html) says means the company provided EPA with technical information on the effectiveness of the product. Treat clothing and gear with products containing 0.5% permethrin, which the CDC says remains protective through several washings; pre-treated clothing and gear can also be purchased. Shower soon after being outdoors: the CDC says showering within two hours of coming indoors has been shown to reduce the risk of getting Lyme disease and may be effective in reducing the risk of other tickborne diseases. Do a full body tick check after returning from potentially tick-infested areas, including your own backyard. The same steps, in order and with the full indoor routine, are in our [Lyme disease prevention guide](https://longsleeve.com/blog/lyme-disease-prevention). If you already have alpha-gal syndrome, prevention is part of managing it. The CDC tells people with the condition to prevent future tick bites because new tick bites may reactivate allergic reactions to alpha-gal, and specifically to wear clothing and gear treated with 0.5% permethrin. The CDC says alpha-gal syndrome should be managed under the care of an allergist or other healthcare provider; these steps belong in that plan. The CDC flags hunters as being at heightened risk, since they spend more time walking through thick grass and densely wooded areas and being low to the ground. ### How is alpha-gal syndrome diagnosed? AGS is diagnosed through a detailed patient history, a physical examination, and a blood test looking for immunoglobulin-E antibodies specific to alpha-gal, known as alpha-gal sIgE. Allergy skin testing for reactions to allergens like pork or beef may also be used. Here is the catch: a positive alpha-gal sIgE test does not mean a person has AGS. Positive results occur in people who do not have AGS, particularly in regions with lone star ticks. The [CDC](https://www.cdc.gov/alpha-gal-syndrome/hcp/diagnosis-testing/index.html) tells providers to weigh results alongside symptoms, whether the reactions are delayed, and history of tick bites or outdoor exposure. Ordered by providers who know AGS and have a high index of suspicion, *MMWR* reports the test shows 98% sensitivity and 92% specificity. Provider familiarity is thin. A web-based survey of 1,500 U.S. health care providers found 42% had never heard of AGS and another 35% were "not too confident" about diagnosing or managing it. Only 5% felt "very confident." Among the 865 who were aware of AGS, 48% did not know the correct diagnostic tests to order. AGS is not a nationally notifiable condition, though your state may require reporting. The Council of State and Territorial Epidemiologists approved a standardized case definition in 2021, which the CDC notes is for surveillance purposes only and does not replace a clinical diagnosis. ### How many people have alpha-gal syndrome? More than 110,000 suspected AGS cases were identified between 2010 and 2022. Because cases are not nationally notifiable, the CDC says the actual number is not known, but as many as 450,000 people may be affected. The underlying study drew on the lab responsible for nearly all U.S. testing before 2022. Between January 1, 2017 and December 31, 2022, 357,119 tests covering 295,400 people were submitted from U.S. residences, and 90,018 of those people (30.5%) tested positive. Annual positives rose from 13,371 in 2017 to 18,885 in 2021. The highest prevalences of suspected cases ran through a nearly contiguous region of the southern, midwestern, and mid-Atlantic United States, particularly parts of Oklahoma, Kansas, Arkansas, Missouri, Mississippi, Tennessee, Kentucky, Illinois, Indiana, North Carolina, Virginia, Maryland, and Delaware. The highest case counts were in Suffolk County, New York (3,746) and Bedford County, Virginia (1,511). A 2026 *MMWR* serosurvey tested 3,000 blood donor samples collected between November 2024 and April 2025 across 10 states. Estimated alpha-gal IgE seroprevalence ranged from 1.1% in Washington to 31.2% in Arkansas, with a combined 24.0% across the five highest states: Arkansas, Kentucky, Missouri, Tennessee, and Virginia. The authors are blunt about the limit of that number. Only a small minority of people who are IgE seropositive actually have AGS, so providers should test only patients with clinically compatible symptoms. ### What are the odds of getting alpha-gal from a tick bite? The CDC does not put a number on it, and neither will we. It says not every person bitten by a lone star, blacklegged, or western blacklegged tick will develop alpha-gal syndrome, that why some people develop it and others do not is not known, and that more research is needed to understand the role ticks play. The sources offer scale and geography. The CDC reports more than 110,000 suspected cases identified between 2010 and 2022, says the actual number is not known because cases are not nationally notifiable, and that as many as 450,000 people may be affected. Most reported cases occur in South, East, and Central states, where the CDC says most lone star ticks are found. The 2026 *MMWR* serosurvey above is a different kind of number: 3,000 blood donor samples from 10 states, collected November 2024 to April 2025, with estimated alpha-gal IgE seroprevalence from 1.1% in Washington to 31.2% in Arkansas. Read it as a map of where the antibody is common, not your odds after a bite. The survey counted antibodies in donated blood; carrying the antibody is not the same as having alpha-gal syndrome, as the diagnosis section above explains. If you are worried after a bite, the CDC's advice for anyone who thinks they may have it: talk to your healthcare provider. ### How is alpha-gal syndrome managed? AGS should be managed under the care of an allergist or other healthcare provider, primarily through an avoidance diet. Most providers recommend that patients stop eating meat from mammals such as beef, pork, lamb, venison, or rabbit. Some patients need to eliminate other sources of alpha-gal, including dairy and certain medications. Beyond meat, the [CDC](https://www.cdc.gov/alpha-gal-syndrome/data-research/products-containing-alpha-gal/index.html) flags gelatin made from beef or pork, products made or cooked with mammal fat such as lard, tallow, or suet, and meat broth, bouillon, stock, and gravy. Some medications and vaccines may contain alpha-gal-containing additives, stabilizers, or coatings, though not all patients react to them. Label reading only goes so far, because cow's milk is the only alpha-gal containing ingredient classified as a major food allergen under federal labeling rules. Foods that do not contain alpha-gal include poultry, fish and seafood, eggs, and fruits and vegetables. A provider may prescribe an epinephrine auto-injector or nasal spray, and the CDC is explicit that people who use them should still seek emergency care. ### Does alpha-gal syndrome ever go away? The CDC says some people with alpha-gal syndrome who avoid additional tick bites may be able to tolerate exposure to alpha-gal containing products again, and calls this an individualized medical decision. That is as far as the CDC goes. The 2023 *MMWR* report states that no treatment or cure is currently available, and the CDC says there are no vaccines to prevent it. Notice the condition: avoid additional tick bites. The same CDC page tells people with alpha-gal syndrome to prevent tick bites because new bites may reactivate allergic reactions to alpha-gal. Tolerance and prevention are the same question. The other reason this belongs with an allergist: variability. The CDC says reactions differ from person to person, range from mild to severe, and some may be life-threatening; a person might not react to every product containing alpha-gal, and some have different symptoms each time they are exposed, even to the same product. A blog cannot tell you which pattern is yours. The CDC says alpha-gal syndrome should be managed under the care of an allergist or other healthcare provider, primarily through an avoidance diet, and that anyone who needs to use a prescribed epinephrine auto-injector or nasal spray should still seek emergency care. If you think you may have it, the CDC's advice is to talk to your healthcare provider. Nothing here is a diagnosis or a substitute for one. ### About Longsleeve Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients. ### Common questions **Does a positive alpha-gal blood test mean I have AGS?** No. The CDC states plainly that a positive alpha-gal sIgE test does not mean a person has AGS, and that positive tests occur in people who do not have AGS, particularly in regions with lone star ticks. Diagnosis requires clinically compatible symptoms alongside the antibody result. **Can I still eat chicken, fish, and eggs?** Yes. The CDC's list of foods that do not contain alpha-gal includes poultry such as chicken, turkey, duck, or quail; fish and seafood such as shrimp; eggs; and fruits and vegetables. **Will one tick bite give you alpha-gal?** Not necessarily. The CDC says not every person bitten by a lone star, blacklegged, or western blacklegged tick will develop alpha-gal syndrome, and the reason certain people develop it and others do not is not known. The CDC states the condition is caused by tick bites, that more research is needed on the role ticks play, and that people of all ages can develop it. **Can you get alpha-gal without a tick bite?** Not according to the CDC, which says alpha-gal syndrome is caused by tick bites, with the caveat that more research is needed to understand the role ticks play. The CDC's position is that alpha-gal syndrome is caused by tick bites, with the caveat that more research is needed to understand the role ticks play. In the United States, the CDC says the lone star tick is most often associated with it, with a few cases reported after blacklegged and western blacklegged tick bites. Per the CDC, the bite can sit weeks to months behind the first symptoms. ### Related reading - [The Lone Star Tick](https://longsleeve.com/blog/lone-star-tick). The white-dot tick behind alpha-gal, and where it lives. - [Vector-Borne Disease in the US, by the Numbers](https://longsleeve.com/blog/vector-borne-disease-numbers). One million reported cases, and what the CDC's counts actually measure. - [Tick Identification Guide](https://longsleeve.com/blog/tick-identification). Which tick bit you, and what it can carry. - [How to Remove a Tick](https://longsleeve.com/blog/tick-removal). Fine-tipped tweezers, straight out, and what to watch for after. - [The almanac of biting insects](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. CDC, About Alpha-gal Syndrome. [https://www.cdc.gov/alpha-gal-syndrome/about/index.html](https://www.cdc.gov/alpha-gal-syndrome/about/index.html) 1. CDC, Symptoms of Alpha-gal Syndrome. [https://www.cdc.gov/alpha-gal-syndrome/signs-symptoms/index.html](https://www.cdc.gov/alpha-gal-syndrome/signs-symptoms/index.html) 1. CDC, Managing Alpha-gal Syndrome. [https://www.cdc.gov/alpha-gal-syndrome/managing/index.html](https://www.cdc.gov/alpha-gal-syndrome/managing/index.html) 1. CDC, Clinical Diagnosis and Testing (Alpha-gal Syndrome). [https://www.cdc.gov/alpha-gal-syndrome/hcp/diagnosis-testing/index.html](https://www.cdc.gov/alpha-gal-syndrome/hcp/diagnosis-testing/index.html) 1. CDC, Fast Facts: Products That May Contain Alpha-gal. [https://www.cdc.gov/alpha-gal-syndrome/data-research/products-containing-alpha-gal/index.html](https://www.cdc.gov/alpha-gal-syndrome/data-research/products-containing-alpha-gal/index.html) 1. Thompson JM, Carpenter A, Kersh GJ, et al. Geographic Distribution of Suspected Alpha-gal Syndrome Cases, United States, January 2017 to December 2022. *MMWR Morb Mortal Wkly Rep* 2023;72(30):815-820. [https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a2.htm](https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a2.htm) 1. Carpenter A, Drexler NA, McCormick DW, et al. Health Care Provider Knowledge Regarding Alpha-gal Syndrome, United States, March to May 2022. *MMWR Morb Mortal Wkly Rep* 2023;72(30):809-814. [https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a1.htm](https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a1.htm) 1. Saunders EF, Taylor ML, Jones ES, et al. Alpha-gal Immunoglobulin E Seroprevalence Among Blood Donors, 10 States, 2024 to 2025. *MMWR Morb Mortal Wkly Rep* 2026;75(25):315-321. [https://www.cdc.gov/mmwr/volumes/75/wr/mm7525a1.htm](https://www.cdc.gov/mmwr/volumes/75/wr/mm7525a1.htm) 1. CDC, Lone Star Tick Surveillance. [https://www.cdc.gov/ticks/data-research/facts-stats/lone-star-tick-surveillance.html](https://www.cdc.gov/ticks/data-research/facts-stats/lone-star-tick-surveillance.html) 1. CDC, Preventing Tick Bites. [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. Butler WK, Oltean HN, Dykstra EA, Saunders E, Salzer JS, Commins SP. Onset of Alpha-Gal Syndrome after Tick Bite, Washington, USA. Emerging Infectious Diseases 2025;31(4).. [https://wwwnc.cdc.gov/eid/article/31/4/24-0577_article](https://wwwnc.cdc.gov/eid/article/31/4/24-0577_article) 1. Saunders EF, Sohail H, Myles DJ, Charnetzky D, Ayres BN, Nicholson WL, Commins SP, Salzer JS. Alpha-Gal Syndrome after Ixodes scapularis Tick Bite and Statewide Surveillance, Maine, USA, 2014 to 2023. Emerging Infectious Diseases 2025;31(4).. [https://wwwnc.cdc.gov/eid/article/31/4/24-1265_article](https://wwwnc.cdc.gov/eid/article/31/4/24-1265_article) 1. Crispell G, Commins SP, Archer-Hartman SA, Choudhary S, Dharmarajan G, Azadi P, Karim S. Discovery of Alpha-Gal-Containing Antigens in North American Tick Species Believed to Induce Red Meat Allergy. Frontiers in Immunology 2019;10:1056.. [https://pmc.ncbi.nlm.nih.gov/articles/PMC6533943/](https://pmc.ncbi.nlm.nih.gov/articles/PMC6533943/) Last reviewed 2026-08-05 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Mosquito With White Stripes: Is It an Asian Tiger Mosquito? URL: https://longsleeve.com/blog/asian-tiger-mosquito > How to tell if the black mosquito with white stripes on its legs and body is an Asian tiger mosquito, why it bites in daylight, and how long its bites last. Source: https://longsleeve.com/blog/asian-tiger-mosquito By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 6, 2026 · Updated September 3, 2026 A small black mosquito, about a quarter inch long, with white bands on its legs and one white stripe running down the center of its head and back is almost certainly the Asian tiger mosquito, *Aedes albopictus*. Illinois health officials say it feeds during daylight hours rather than at night, and it lays its eggs in water-filled containers rather than ditches or marshes. ### Is this the mosquito with white stripes on its body? Almost certainly, yes. A small black mosquito with white bands on its legs and a single white stripe running down the center of its head and back is the Asian tiger mosquito, *Aedes albopictus*. The Illinois Department of Public Health describes it as a small black and white mosquito about a quarter inch long, and says the name comes from its white and black color pattern: a white stripe running down the center of its head and back, with white bands on the legs. The CDC's card for the species reads black, white bands on the legs, white spots on the body. White dots, white spots, white stripes: same insect. One check first. Illinois DPH notes that other mosquitoes in its state also have banded legs, so striped legs alone do not settle it. The tell is the single white stripe down the middle of the head and back. Some people read the legs as blue; the CDC and Illinois DPH both describe them as white bands on black, and neither mentions any other color. Size is the other clue. Illinois DPH gives about a quarter inch. The California Department of Public Health (CDPH) shows the invasive *Aedes* species at one eighth to one quarter inch, and says these mosquitoes only live near people, which fits a mosquito found on your own arm. ### How do you identify an Asian tiger mosquito? The CDC lists the distinguishing features of *Aedes albopictus* as "Black; white bands on the legs; white spots on the body." Its close relative *Aedes aegypti*, the yellow fever mosquito, is "Dark brown; white bands on the legs; white spots on the body, and stripes on the upper body that look like a lyre." ### What is the difference between a normal mosquito and a tiger mosquito? Three visible differences. First, timing. Illinois DPH says that unlike many other mosquitoes in its state, the Asian tiger feeds during daylight hours, not at night. CDPH gives daytime and near dawn and dusk, and calls it an aggressive day-biter, indoors and out. The CDC says *Aedes* species mosquitoes can bite during the day and night. Second, breeding sites. Illinois DPH says these mosquitoes lay their eggs in water-filled natural and artificial containers, such as tree cavities and old tires, and not in ditches or marshes. CDPH puts the container as small as a bottle cap. Third, how it looks: Illinois DPH says banded legs are not unique to this species, so look for the white stripe down the head and back. It shares one thing with every mosquito: only females bite. The CDC says females need a blood meal to produce eggs; Illinois DPH adds that males feed on plant juices and do not bite. The life cycle is short. The [CDC](https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html) puts egg to adult at 7 to 10 days and says eggs can survive drying out for up to 8 months. Illinois DPH says that in summer, adults emerge in as little as 10 to 14 days after the eggs hatch, and that the species overwinters as eggs, hatching when water covers them in spring and summer. ### Asian tiger mosquito vs Aedes aegypti: how to tell them apart The two invasive *Aedes* species overlap enough to be confused. CDPH describes both as small, black mosquitoes with white stripes on their back and legs that only live near people. The split is on the back: one white stripe for the tiger mosquito, a lyre-shaped pattern for *Aedes aegypti*. Every cell below traces to the CDC's Most (un)Wanted Mosquitoes page unless another source is named. | Feature | *Aedes albopictus* (Asian tiger mosquito) | *Aedes aegypti* (yellow fever mosquito) | |---|---|---| | Body color | Black (CDC) | Dark brown (CDC). CDPH describes both species as black | | Leg bands | White bands on the legs (CDC) | White bands on the legs (CDC) | | Upper body pattern | White spots on the body (CDC); a single white stripe running down the center of the head and back (Illinois DPH) | White spots on the body, and stripes on the upper body that look like a lyre (CDC) | | Range, as CDC lists it | Southern and Southwestern U.S. states; tropical, subtropical, and some temperate areas of the world, including countries in Africa and Asia and parts of southern Europe | Southern and Southwestern U.S. states and Puerto Rico; tropical and subtropical areas of the world, including countries in Africa and Asia and parts of southern Europe | | Diseases CDC associates with it | Dengue, Zika, chikungunya. CDC adds that because it feeds on animals as well as people, it is less likely to spread these and other viruses than *Aedes aegypti*. | Dengue, Zika, chikungunya, and yellow fever. | | Temperature tolerance | Can live in a broader temperature range and at cooler temperatures than *Aedes aegypti* (CDC) | The less cold-tolerant of the two, by CDC's comparison; no figure given | ### Why is it biting me in the middle of the day? Because that is when it hunts. CDPH states that *Ae. aegypti* and *Ae. albopictus* "are aggressive day-biters found both indoors and outdoors" and "especially like to feed on ankles, wrists, and elbows." Its field guide gives the biting window as "Daytime, and near dawn and dusk." In the CDC journal Emerging Infectious Diseases in 2015, CDPH authors agreed: "These mosquitoes are daytime biters, need only small water containers to propagate, and are difficult to eradicate." Only females bite: per the [CDC](https://www.cdc.gov/mosquitoes/about/index.html), "Female mosquitoes need a blood meal to produce eggs." CDPH notes that "even a small number of mosquitoes can become an extreme nuisance," and a 1997 CDC review of the species' first decade in the United States called it "a major biting pest throughout much of its range." Illinois DPH puts it plainly: unlike many other mosquitoes in its state, the Asian tiger feeds during daylight hours, not at night. That habit has a consequence for control. Because the mosquito is active during the day, Illinois DPH says fogging, the space spraying done from specially equipped trucks, provides little control, since the method is generally ineffective in daylight atmospheric conditions. As for why it picked you: Illinois DPH says that, as with other mosquitoes, Asian tiger mosquitoes are attracted to dark clothing, perspiration, carbon dioxide, and certain other odors. Daylight is the time of day. For the time of year, see our guide to [mosquito season by region](https://longsleeve.com/blog/mosquito-season-by-region). ### Are Asian tiger mosquito bites worse than other mosquito bites? Nothing in our sources says so. Illinois DPH says the bite of the Asian tiger mosquito is not particularly irritating to most people, and no health agency in our sources ranks one species' bite as harsher than another's. What Illinois DPH does say is that they are persistent biters, and persistence is the part people feel. CDPH calls them aggressive day-biters, found indoors and outdoors, that especially like to feed on ankles, wrists, and elbows. And because they breed in nearly any water-filled container, Illinois DPH says they often become very common and bothersome even in neighborhoods where mosquitoes are normally few. Put those together and you get the experience people describe: several bites in one sitting, low on the body, in daylight, in a neighborhood that normally has few mosquitoes. The CDC says your body reacts to the mosquito's saliva, and that reaction is what produces the bump and the itching. Its list of bite signs includes multiple bumps appearing a day or so after the bites, which is the mark a persistent biter leaves. ### Can Asian tiger mosquitoes bite through clothes? They may, through thin fabric, according to Illinois DPH. None of our sources says whether this species is better or worse at it than any other, so the answer here is about mosquitoes in general. Illinois DPH says mosquitoes may bite through thin fabric, and that long-sleeved tops and long pants made of tightly woven materials keep mosquitoes away from the skin. Note the qualifier: tightly woven. The [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html)'s clothing guidance is to wear loose-fitting, long-sleeved shirts and pants, and to wear clothing and gear treated with permethrin, which it says should not be used directly on skin. Illinois DPH arrives at the same place from the other side: repellents such as permethrin can be applied to clothing rather than skin, precisely because mosquitoes may bite through thin fabric. Treating the fabric is a different job from treating your skin, and we walk through what it involves in our guide to [permethrin-treated clothing](https://longsleeve.com/blog/permethrin-clothing). ### How long do Asian tiger mosquito bites last? Three or four days for the itch. The [American Academy of Pediatrics](https://www.healthychildren.org/English/tips-tools/symptom-checker/Pages/symptomviewer.aspx?symptom=Mosquito+Bite) says most mosquito bites itch for 3 or 4 days, any pinkness or redness lasts 3 or 4 days, and the swelling may last 7 days. Those are figures for mosquito bites generally; no source of ours times this species separately. The CDC says your body reacts to the mosquito's saliva, which is what produces the bump and the itching. A 2022 review in Frontiers in Immunology gives the sequence: immediately after the bite, a round wheal 2 to 10 mm across forms, with surrounding redness that peaks in 20 to 30 minutes. The delayed reaction is itchy papules of the same size, peaking in 24 to 36 hours and fading over several days. The [CDC](https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html)'s plainer version: a puffy, reddish bump a few minutes after the bite, then a hard, itchy, reddish-brown bump, or multiple bumps, a day or so later. One exception: young children. The AAP says that in young children the redness can be 2 to 4 inches, and that it may keep getting larger for 2 to 3 days. That is still normal. For what to put on the bite, see our guide to [mosquito bite treatment](https://longsleeve.com/blog/mosquito-bite-treatment). For anything beyond an ordinary reaction, ask a clinician. ### Where does the Asian tiger mosquito breed? In containers. Not marshes, not ponds, containers. The CDC describes the egg-laying step precisely: "Adult female mosquitoes lay eggs on the inner walls of containers with water, above the waterline," and "Eggs stick to container walls like glue." It adds that "Mosquitoes only need a small amount of water to lay eggs." The EPA names the same insect. After listing tree holes, old tires, buckets, toys, potted plant trays and saucers, and "places as small as bottle caps," it says "Some of the most annoying and potentially dangerous mosquito species, such as the Asian tiger mosquito, come from these sites." CDPH adds that the species "thrives in urban areas." Two features make the eggs hard to starve out: per the CDC they "can survive drying out for up to 8 months" and "can even survive a winter in the southern United States." Eggs hatch when water covers them, and the CDC puts egg to adult at 7 to 10 days. ### How far do Asian tiger mosquitoes travel from where they breed? Three sources give three figures. Illinois DPH says the Asian tiger mosquito usually does not fly more than about half a mile from its breeding site. The CDC says *Aedes aegypti* and *Ae. albopictus* do not fly long distances and will only fly a few blocks in their lifetime. A 2019 mark-release-recapture study in Parasites & Vectors, run in Coldrerio and Lugano, two areas of intensive control in Switzerland, found that 77.5 percent of recaptured *Ae. albopictus* flew further than 250 metres, the limit usually deemed sufficient for vector containment. Only 49 mosquitoes were recaptured, 40 in Coldrerio and 9 in Lugano. We give all three rather than average them. Whichever figure you take, the container producing the mosquitoes that bite you is probably close by: the CDC says these mosquitoes will only fly a few blocks in their lifetime. Illinois DPH says they lay eggs in water-filled containers, natural or artificial, not ditches or marshes, and that because nearly any water-filled container will do, they often become very common even in neighborhoods where mosquitoes are normally few. CDPH puts the minimum at a container as small as a bottle cap and notes the species thrives in urban areas. The [CDC](https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-at-home.html)'s fix is a weekly habit: once a week, empty and scrub, turn over, cover, or throw out any items that hold water. ### How far has it spread in the United States? Fast, and probably on trucks. CDC's Emerging Infectious Diseases review reports that established populations "were first discovered in the continental United States in Harris County, Texas, in August 1985," and that the mosquito "probably entered the United States in shipments of used tires from northern Asia." Federal rules followed late. Used tires from infested areas had to be dry, clean, and fumigated starting January 1, 1988, and by then "existing populations had become established in 15 states." Early spread tracked the road network: of 92 infested counties in December 1987, 64 sat on an interstate highway. The authors note the pattern can be explained in other ways. A CDC-led survey in the Journal of Medical Entomology gives the most recent county tally we could verify. Between January 1995 and March 2016, "1,241 counties from 40 states and the District of Columbia reported occurrence of *Ae. albopictus*," and the species "was collected during 3 or more years from 514 counties in 34 states and the District of Columbia." A county with no reported records, the authors warn, "should not necessarily be interpreted as the given species being absent." Cold is less of a barrier than people assume. The CDC says *Ae. albopictus* "can live in a broader temperature range and at cooler temperatures than *Ae. aegypti*," and the same survey notes it can establish "overwintering populations farther north." CDPH researchers reported that after a 2011 detection in Los Angeles County, surveillance documented spread "to 12 surrounding cities." The [CDC](https://www.cdc.gov/mosquitoes/php/toolkit/potential-range-of-aedes.html) cautions that its range maps "do not represent risk for spread of disease." ### What diseases can Aedes albopictus transmit? The [CDC](https://www.cdc.gov/dengue/stories/unwanted-mosquitoes.html) lists this mosquito's record as "Spreading dengue, Zika, chikungunya," with an important qualifier attached: "because these mosquitoes feed on animals as well as people, they are less likely to spread these and other viruses than the *Aedes aegypti*." CDC's vector control manual adds yellow fever to that list, footnoting *Ae. albopictus* as an "Unproven vector of yellow fever virus." Laboratory competence runs broader than field evidence. CDC's 1997 review found the species to be a competent experimental vector of seven alphaviruses, including chikungunya and eastern equine encephalitis, and of flaviviruses including all four dengue serotypes, Japanese encephalitis, West Nile, and yellow fever. It concluded, at the time, that "evidence is lacking to incriminate *Ae. albopictus* as the vector of even a single case of human disease in the United States." In 2001, researchers reported "the first isolation of LAC virus from naturally infected *Ae. albopictus* mosquitoes," collected around patients' homes in Tennessee and North Carolina, and concluded it "may become an important accessory vector of LAC virus." The CDC says recent U.S. outbreaks of chikungunya and dengue "have been relatively small and limited to a small area." For La Crosse virus, most infected people have no symptoms, severe disease "occurs most often in children under 16 years old," and "No vaccines or medicines are available to prevent La Crosse." For dengue, symptoms typically last 2 to 7 days, "About 1 in 20 people who get sick with dengue will develop severe dengue," and "Severe dengue is a medical emergency." ### What actually reduces Asian tiger mosquitoes around a home? Source reduction. The CDC's home guidance leads with it: "Once a week, empty and scrub, turn over, cover, or throw out any items that hold water like tires, buckets, planters, toys, pools, birdbaths, flowerpot saucers, or trash containers." The scrubbing is not decoration. Eggs are glued to the walls above the waterline, so tipping the bucket leaves them behind. The rest of the CDC's list: - Tightly cover buckets, cisterns, and rain barrels so mosquitoes cannot get inside to lay eggs. - For containers without lids, use wire mesh with holes smaller than an adult mosquito. - Fill tree holes to prevent them from filling with water. - Repair cracks or gaps in a septic tank, and cover open vent or plumbing pipes. - Use larvicides on water that cannot be covered or dumped out, always following label instructions. Indoors, the CDC gives the same weekly instruction for vases and flowerpot saucers, plus screens and air conditioning, noting that "Mosquitoes entering your house from outdoors can start laying eggs indoors." The EPA frames the same strategy in cost terms. "The greatest impact on mosquito populations will occur when they are concentrated, immobile and accessible," and "Egg and larva interventions are generally the most effective, least costly, way to control mosquitoes." It is honest about the ceiling: those interventions are "unlikely to be 100% effective." Neighbors matter, and the EPA calls community involvement "essential." For water you cannot dump, the CDC says homeowners can use larvicide dunks or bits, following the label. For personal protection, the CDC recommends EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone. It tells consumers to "Look for an EPA registration number (EPA Reg. No.) on the insect repellent product label," follow label instructions, and reapply as directed. It also recommends loose-fitting long sleeves and pants, and permethrin-treated clothing and gear, which it says should not be used directly on skin. The CDC recommends active ingredients, not brands. ### When should you call someone? Two different calls. For the mosquitoes, CDPH says to "Contact your local vector control agency if you detect unusual numbers of mosquitoes or you are being bitten during the day," though the [CDC](https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-programs.html) notes that "Mosquito control efforts and capabilities vary across the United States." For symptoms, the CDC says to see your healthcare provider if you have signs of dengue and live in or recently traveled to an area with risk, and to go straight to a clinic or emergency room for warning signs of severe dengue. Diagnosis belongs with a clinician, not a website. ### Where Longsleeve fits Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients. ### Common questions **How do I tell an Asian tiger mosquito from a yellow fever mosquito?** Look at the back. CDPH describes Aedes albopictus as black with one white "racing" stripe on its thorax, and Aedes aegypti as dark brown with two stripes shaped like a lyre. **Do they really bite in the middle of the day?** Yes. CDPH calls both invasive Aedes species "aggressive day-biters found both indoors and outdoors." The CDC says Aedes species mosquitoes can bite during the day and night. **How small a container can they breed in?** Very small. The EPA lists breeding sites down to "places as small as bottle caps." The CDC says the eggs can survive drying out for up to 8 months. **If I dump the water, will they come back from somewhere else?** Less than you would think. The CDC says these mosquitoes do not fly long distances and will only fly a few blocks in their lifetime. The EPA notes that habitat removal alone is unlikely to be 100 percent effective and calls community involvement essential. We publish the primary-source backing for claims like these on our facts page . **Do Asian tiger mosquitoes bite at night too?** Mostly no. Illinois DPH says the Asian tiger feeds during daylight hours, not at night, unlike many other mosquitoes in its state. CDPH gives the biting window as daytime and near dawn and dusk. The CDC's general statement is that Aedes species mosquitoes can bite during the day and night. Daylight is the pattern; the CDC does not rule out the dark. **Do they bite pets and wildlife as well as people?** Yes. Illinois DPH says the mosquito will bite squirrels, dogs, deer and other animals as well as people. Only females do it: the CDC says female mosquitoes bite people and animals to get a blood meal, which they need to produce eggs, and Illinois DPH notes that males feed on plant juices and do not bite. ### Related reading - [Aedes aegypti: The Yellow Fever Mosquito](https://longsleeve.com/blog/aedes-aegypti). The day-biting container breeder behind dengue and Zika. - [Standing Water and Mosquito Control](https://longsleeve.com/blog/standing-water-mosquito-control). The only home control with real evidence behind it. - [West Nile Virus in the United States](https://longsleeve.com/blog/west-nile-virus). The bird cycle, the late-summer peak, and who is actually at risk. - [Our field guide to biting insects](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. - [Dengue and Travel](https://longsleeve.com/blog/dengue-travel). Where the risk is concentrated and what to do before you go. More Longsleeve in your Google feed: ### Sources 1. CDC, Life Cycle of Aedes Mosquitoes. [https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html](https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html) 1. CDC, Mosquito Control at Home. [https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-at-home.html](https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-at-home.html) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC, Larvicides. [https://www.cdc.gov/mosquitoes/mosquito-control/larvicides.html](https://www.cdc.gov/mosquitoes/mosquito-control/larvicides.html) 1. CDC, What Mosquito Control Programs Do. [https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-programs.html](https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-programs.html) 1. CDC, About Mosquitoes. [https://www.cdc.gov/mosquitoes/about/index.html](https://www.cdc.gov/mosquitoes/about/index.html) 1. CDC, Potential Range of Aedes Mosquitoes. [https://www.cdc.gov/mosquitoes/php/toolkit/potential-range-of-aedes.html](https://www.cdc.gov/mosquitoes/php/toolkit/potential-range-of-aedes.html) 1. CDC, CDC's Most (un)Wanted Mosquitoes. [https://www.cdc.gov/dengue/stories/unwanted-mosquitoes.html](https://www.cdc.gov/dengue/stories/unwanted-mosquitoes.html) 1. CDC, How Dengue Spreads. [https://www.cdc.gov/dengue/transmission/index.html](https://www.cdc.gov/dengue/transmission/index.html) 1. CDC, Symptoms of Dengue and Testing. [https://www.cdc.gov/dengue/signs-symptoms/index.html](https://www.cdc.gov/dengue/signs-symptoms/index.html) 1. CDC, About La Crosse Virus. [https://www.cdc.gov/la-crosse-encephalitis/about/index.html](https://www.cdc.gov/la-crosse-encephalitis/about/index.html) 1. CDC, Surveillance and Control of Aedes aegypti and Aedes albopictus in the United States. [https://www.cdc.gov/mosquitoes/pdfs/mosquito-control-508.pdf](https://www.cdc.gov/mosquitoes/pdfs/mosquito-control-508.pdf) 1. Aedes albopictus in the United States: Ten-Year Presence and Public Health Implications. Emerging Infectious Diseases, Volume 3, Number 3, September 1997. [https://wwwnc.cdc.gov/eid/article/3/3/97-0309_article](https://wwwnc.cdc.gov/eid/article/3/3/97-0309_article) 1. Gerhardt RR, Gottfried KL, Apperson CS, Davis BS, Erwin PC, Smith AB, Panella NA, Powell EE, Nasci RS. First Isolation of La Crosse Virus from Naturally Infected *Aedes albopictus*. Emerging Infectious Diseases, Volume 7, Number 5, October 2001. [https://wwwnc.cdc.gov/eid/article/7/5/01-7506_article](https://wwwnc.cdc.gov/eid/article/7/5/01-7506_article) 1. Porse CC, Kramer VL, Yoshimizu MH, Metzger ME, Hu R, Padgett K, Vugia D. Public Health Response to *Aedes aegypti* and *Ae. albopictus* Mosquitoes Invading California, USA. Emerging Infectious Diseases, Volume 21, Number 10, October 2015. [https://wwwnc.cdc.gov/eid/article/21/10/15-0494_article](https://wwwnc.cdc.gov/eid/article/21/10/15-0494_article) 1. Hahn MB, Eisen RJ, Eisen L, Boegler KA, Moore CG, McAllister J, Savage HM, Mutebi JP. Reported Distribution of *Aedes* (*Stegomyia*) *aegypti* and *Aedes* (*Stegomyia*) *albopictus* in the United States, 1995 to 2016 (Diptera: Culicidae). Journal of Medical Entomology, 2016;53(5):1169-1175. [https://stacks.cdc.gov/view/cdc/120311/cdc_120311_DS1.pdf](https://stacks.cdc.gov/view/cdc/120311/cdc_120311_DS1.pdf) 1. Active dispersal of *Aedes albopictus*: a mark-release-recapture study using self-marking units. Parasites & Vectors, 2019. doi:10.1186/s13071-019-3837-5. [https://pmc.ncbi.nlm.nih.gov/articles/PMC6909613/](https://pmc.ncbi.nlm.nih.gov/articles/PMC6909613/) 1. EPA, General Information about Mosquitoes. [https://www.epa.gov/mosquitocontrol/general-information-about-mosquitoes](https://www.epa.gov/mosquitocontrol/general-information-about-mosquitoes) 1. EPA, Success in Mosquito Control: An Integrated Approach. [https://www.epa.gov/mosquitocontrol/success-mosquito-control-integrated-approach](https://www.epa.gov/mosquitocontrol/success-mosquito-control-integrated-approach) 1. California Department of Public Health, Aedes aegypti and Aedes albopictus Mosquitoes. [https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Aedes-aegypti-and-Aedes-albopictus-mosquitoes.aspx](https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Aedes-aegypti-and-Aedes-albopictus-mosquitoes.aspx) 1. California Department of Public Health, Guide to Important Mosquitoes in California. [https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/GuidetoImportantMosquitoesinCA.pdf](https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/GuidetoImportantMosquitoesinCA.pdf) 1. California Department of Public Health, Invasive Mosquitoes brochure. [https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/InvasiveMosquitoesBrochure.pdf](https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/InvasiveMosquitoesBrochure.pdf) 1. Illinois Department of Public Health, Asian Tiger Mosquito. [https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/asian-tiger-mosquito.html](https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/asian-tiger-mosquito.html) 1. Illinois Department of Public Health, DEET Insect Repellents. [https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/deet-insect-repellents.html](https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/deet-insect-repellents.html) 1. American Academy of Pediatrics, HealthyChildren.org, Mosquito Bite. [https://www.healthychildren.org/English/tips-tools/symptom-checker/Pages/symptomviewer.aspx?symptom=Mosquito+Bite](https://www.healthychildren.org/English/tips-tools/symptom-checker/Pages/symptomviewer.aspx?symptom=Mosquito+Bite) 1. Frontiers in Immunology, 2022 Sep 21, volume 13, article 1024559. [https://pmc.ncbi.nlm.nih.gov/articles/PMC9532860/](https://pmc.ncbi.nlm.nih.gov/articles/PMC9532860/) 1. CDC, About Mosquito Bites. [https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html](https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html) Last reviewed 2026-08-06 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Black Fly Bites: Swelling, Bleeding, Treatment, and Prevention URL: https://longsleeve.com/blog/black-fly-bites > Why black fly bites swell, bleed, and heal slowly, what CDC bite care says to do, when infected-bite signs matter, and how hats, clothing, repellent, and head nets help. Source: https://longsleeve.com/blog/black-fly-bites By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 26, 2026 Black fly bites bleed and swell more than mosquito bites, and Illinois DPH says they are often itchy and slow to heal, aimed at the head and wherever clothing fits tightly. Treat them with CDC bite care: soap and water, ice for 10 minutes, anti-itch cream, and no scratching. If a spring hike near a river left you with bloody, swollen bites along your hairline and collar, you met black flies. They are the meanest biters most people in the northern half of the country will encounter, and they punch far above their eighth-of-an-inch weight. Here is what they are, what their bites do, and what actually helps. ### What are black flies? The Illinois Department of Public Health describes them precisely: adult black flies are small, no more than 1/8 inch long, with broad wings and a humpbacked appearance. They are also known as "buffalo gnats," and they are creatures of moist environments, usually encountered near creeks and rivers, where their larvae attach to submerged stones. **Short answer:** Illinois DPH says black fly bites often cause considerable swelling and bleeding, may itch, and can be slow to heal. Treat them with CDC bite care: wash with soap and water, ice for 10 minutes, use an over-the-counter anti-itch or antihistamine cream as directed, and do not scratch. Watch for infection signs like warmth, redness, or a red streak spreading outward. ### Why are the bites so bad? Illinois DPH does not soften it: "Black fly bites often cause considerable swelling and bleeding, may be itchy and slow to heal." And they are targeted: black flies "prefer to attack the head and where clothing fits tightly," which is why the bites line up along hairlines, ears, collars and waistbands. At the extreme, the department notes that when black flies are present in very large numbers, injury from their bites can threaten the lives of livestock and even people, with deaths reported from allergic reactions and blood loss. That is the mass-swarm scenario, not the day hike, but it is why northern outbreak years make the news. One piece of genuinely good news, again from Illinois DPH: black flies "do not transmit disease to humans in the United States." The bite is the whole problem. That puts the black fly in a different category from the mosquito and the tick: what you are managing is pain, swelling and healing time, not an infection watch. It also explains why the prevention advice leans so hard on physical barriers. There is no disease calculus to weigh; there is only whether the fly reaches skin. ### How do you treat black fly bites? The CDC's insect bite-care steps are the playbook: - **Wash the bite and surrounding area with soap and water.** - **Ice it.** An ice pack for 10 minutes reduces swelling and itching, and with black fly bites the swelling is usually the worst part. Reapply as needed. - **Use an over-the-counter anti-itch or antihistamine cream,** following the product label directions. - **Do not scratch.** The CDC's warning: "Do not scratch bites. They can become infected." Since black fly bites are slow healers already, scratching sets you back the most here. Watch the infected-bite signs the CDC lists: redness, warmth, or a red streak spreading outward. See a healthcare provider if symptoms worsen. The bump and itch themselves are your body reacting to the fly's saliva, the same mechanism the CDC describes for mosquito bites, just delivered by a messier bite. ### How do you keep black flies off? The Illinois DPH prescription, in order: - **Repellent.** Those containing DEET or picaridin "are best," with the caveat that repellents can be less effective against some biting flies than against mosquitoes, so do not make repellent the whole plan. - **Clothing that denies the target.** Heavy-duty, light-colored clothing with long sleeves, long pants and hats. Black flies aim for the head and tight clothing lines, so a hat is not an accessory here, it is armor. - **The head net, when it is bad.** The department's own escalation: when black flies are numerous and unavoidable, "netting that covers the head, like the 'bee bonnets' used by beekeepers, can provide protection." Every northern trail town sells them for a reason. - **Timing.** Late spring and early summer near running water is the peak. Avoiding the riverside at the height of the hatch is the cheapest protection there is. Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours, and its accepted federal label carries the claim "Repels biting flies, stable flies, black flies, gnats, chiggers, sand flies and Scottish biting midges (no see-ums) for up to 8 hours." It is fragrance-free, with nine disclosed ingredients. Of the 631 EPA-registered skin repellents in [our Repellent Index](https://longsleeve.com/repellent-index), 130 carry a stated fly protection time on their federal label. ### Short answers **Why do black fly bites bleed?** Illinois DPH describes black fly bites as often causing considerable swelling and bleeding, and notes they may be itchy and slow to heal. That is the observed character of the bite; the department's practical advice is to prevent them with repellent, clothing and, when swarms are heavy, a head net. **How long do black fly bites take to heal?** Longer than you want. Illinois DPH describes the bites as slow to heal on top of the swelling and bleeding, and the CDC's no-scratching rule is what protects that slow healing from becoming an infected bite: redness, warmth, or a spreading red streak means a provider visit. **Do black flies carry disease?** Per Illinois DPH, black flies do not transmit disease to humans in the United States. The concern is the bites themselves: swelling, bleeding, slow healing, and in mass-swarm conditions, allergic reactions. **Why do the bites swell so much?** The swelling is your body's reaction to the fly's saliva, the same mechanism the CDC describes for mosquito bites: saliva goes in as the insect feeds, and the reaction produces the bump and the itch. Black fly bites add bleeding and a slower heal on top, per Illinois DPH, which is why the CDC's ice-pack step earns its place here. **Why do black flies go for my head?** Illinois DPH: they prefer to attack the head and wherever clothing fits tightly. A hat and, in bad stretches, a head net are the department's answer. **When is black fly season?** Late spring and early summer, per Illinois DPH, when they can appear in very large numbers near the creeks and rivers where their larvae grow. They range up to 10 miles from the water, so distance is only partial protection. Gear up before the hatch: [the black fly repellent guide](https://longsleeve.com/blog/black-fly-repellent). Smaller but just as annoying: [no-see-ums](https://longsleeve.com/blog/no-see-ums). ### Related reading - [Black Fly Repellent](https://longsleeve.com/blog/black-fly-repellent). DEET, picaridin, clothing, and timing. - [No-See-Um Bites](https://longsleeve.com/blog/no-see-um-bites). Why they itch, how long they last, and how to treat them. - [Mosquito Bite Treatment](https://longsleeve.com/blog/mosquito-bite-treatment). Itch relief, swelling, infection signs, and when to seek care. - [Gnat Repellent](https://longsleeve.com/blog/gnat-repellent). Biting midges, labels, screens, and fans. - [The species almanac](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. Illinois Department of Public Health, Biting Flies. [https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html](https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html) 1. CDC, About Mosquito Bites. [https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html](https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html) Last reviewed 2026-08-26 · every claim on this page is sourced above ## Black Fly Repellent: DEET, Picaridin, Clothing, and Timing URL: https://longsleeve.com/blog/black-fly-repellent > How to choose black fly repellent for buffalo gnat season using Illinois DPH and EPA guidance, including DEET, picaridin, hats, light-colored clothing, and head nets. Source: https://longsleeve.com/blog/black-fly-repellent By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 26, 2026 Illinois DPH names DEET and picaridin as the actives to look for against biting flies, paired with light-colored long sleeves, pants and a hat, and a head net when swarms are unavoidable. Black flies target the head, so what you wear matters as much as what you apply. Black fly season is short and it is vicious: a few weeks in late spring and early summer when the rivers hatch and the "buffalo gnats" come looking for blood, up to 10 miles from the water they grew in. There is a well-established playbook for it, straight from public health guidance, and it has more moving parts than a bottle. ### What does the guidance say to use? The Illinois Department of Public Health, in its biting flies guidance: repellents "containing the active ingredient DEET (N,N-diethyl-meta-toluamide) or picaridin are best." Then the sentence every honest black fly page has to include: "While effective against mosquitoes, repellents have been found to be less effective against some types of biting flies," and their use "should be supplemented with other preventive methods, such as avoiding areas inhabited by the flies, avoiding peak biting times, and wearing heavy-duty, light-colored clothing including long-sleeve shirts, long pants and hats." **Short answer:** Illinois DPH names DEET and picaridin as the actives to look for against biting flies, with an important caveat: repellents can be less effective against some biting flies than against mosquitoes. For black flies, pair repellent with heavy-duty, light-colored long sleeves and pants, a hat, and a head net when swarms are unavoidable. Always follow the product label. ### Why does clothing matter so much for black flies? Because of where they bite. Illinois DPH: black flies "prefer to attack the head and where clothing fits tightly." A hat covers the preferred target. Loose, heavy, light-colored fabric removes the tight-fit lines they work along. And when they are at their worst, the department's own escalation is the beekeeper move: when black flies are "numerous and unavoidable, netting that covers the head, like the 'bee bonnets' used by beekeepers, can provide protection." The season and geography tell you when to bother: late spring and early summer, near creeks and rivers where the larvae attach to submerged stones, with adults ranging up to 10 miles out. One mercy, per the same guidance: black flies do not transmit disease to humans in the United States. ### What should you check on the repellent label? Fly claims are registered pest by pest, and EPA's consumer search tool only filters by mosquitoes and ticks, so a black-fly answer has to come off the product's own federal label. [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively)'s rule: "always read the product label before using the product." We read all of them. [The Repellent Index](https://longsleeve.com/repellent-index) holds the 631 EPA-registered skin-applied repellents with the pest claims on each federal label: 130 of them carry a stated fly protection time. The [statistics page](https://longsleeve.com/repellent-index/statistics) has the full breakdown, and the dataset is free to download. Then apply it properly, per EPA: follow the label directions, be sure you understand how much to apply, and apply only to exposed skin and/or clothing, never under clothing. For children, EPA's rule is specific: do not allow children to handle the product and do not apply it to their hands; apply to your own hands first, then put it on the child. On a black fly trip that matters doubly, because the skin children most need covered, the hairline, ears and neck, is exactly where an adult's hands-first application does the neatest job. ### Why the plan has so many parts Because the agency guidance itself is layered. Illinois DPH does not present repellent as sufficient for biting flies; it presents it as the base layer of a plan that includes avoiding the areas the flies inhabit, avoiding their peak biting times, and dressing against them. Black flies concentrate that logic: they are seasonal (late spring and early summer), geographic (near running water, with a 10-mile reach), and targeted (the head, and tight clothing lines). Each of those facts maps to a countermeasure, and the countermeasures stack. A hat plus repellent beats either alone; both plus a loose light-colored shirt beats that; and the head net is the ceiling for the days when nothing else is enough. ### The buffalo gnat checklist - **Repellent with DEET or picaridin** on exposed skin, per Illinois DPH. - **A label that mentions flies.** 130 of 631 registered products state a fly protection time. - **Hat on.** The head is their preferred target. - **Light-colored, heavy-duty, loose clothing:** long sleeves, long pants. - **Head net in the pack** for the days they are unavoidable. - **Timing:** the hatch peaks late spring to early summer near running water. Plan the riverside lunch for July. Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours, and its accepted federal label carries the claim "Repels biting flies, stable flies, black flies, gnats, chiggers, sand flies and Scottish biting midges (no see-ums) for up to 8 hours." It is fragrance-free, with nine disclosed ingredients. ### Short answers **What is the best black fly repellent?** No agency ranks products. Illinois DPH names DEET and picaridin as the actives to look for against biting flies, notes repellents can be less effective on some biting flies than on mosquitoes, and pairs them with clothing, hats and head nets. Check the individual product's federal label for a fly claim. **Do black flies bite through clothing?** Their pattern, per Illinois DPH, is to attack the head and wherever clothing fits tightly. The department's guidance is heavy-duty, loose, light-colored clothing, which removes the tight-fit lines they exploit. **When do I actually need a head net?** Illinois DPH's threshold: when black flies are numerous and unavoidable. In a bad hatch year near running water, that describes most of late spring. **Why is black fly season so short and so intense?** The population peaks when the rivers hatch, and Illinois DPH notes they can be present in very large numbers in late spring and early summer, in concentrations that can threaten livestock and even people through allergic reactions and sheer volume of bites. The same concentration means the season burns out: by midsummer the pressure drops sharply. **How far from a river can black flies find me?** Up to 10 miles, per Illinois DPH. Distance from water helps, but inside that radius the clothing-plus-repellent plan is what protects you. Already bitten? [Black fly bites: why they bleed and what helps](https://longsleeve.com/blog/black-fly-bites). The tiny cousins: [gnats](https://longsleeve.com/blog/gnat-repellent) and [no-see-ums](https://longsleeve.com/blog/no-see-um-repellent). ### Related reading - [Black Fly Bites](https://longsleeve.com/blog/black-fly-bites). Swelling, bleeding, treatment, and prevention. - [Gnat Repellent](https://longsleeve.com/blog/gnat-repellent). Biting midges, labels, screens, and fans. - [No-See-Um Repellent](https://longsleeve.com/blog/no-see-um-repellent). Check the label for biting midges. - [Picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet). Duration, kids, ticks, and materials. More Longsleeve in your Google feed: ### Sources 1. Illinois Department of Public Health, Biting Flies. [https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html](https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html) 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) Last reviewed 2026-08-26 · every claim on this page is sourced above ## Bug Spray and Sunscreen: Which Goes On First, and Why No Combo URL: https://longsleeve.com/blog/bug-spray-and-sunscreen > Sunscreen first, let it dry, then repellent. DEET over sunscreen cuts SPF by a third; the repellent keeps working. Why combos fail, and the picaridin studies. Source: https://longsleeve.com/blog/bug-spray-and-sunscreen By [Andrew Rothaus](https://longsleeve.com/about), Founder · September 9, 2026 **Short answer:** Sunscreen first, then repellent, as two separate products, and let the sunscreen dry before the repellent goes on. That is the CDC's guidance and the American Academy of Pediatrics'. A human urinary study that tested the order recommends a 15 minute gap. Then reapply each on its own schedule, and skip the combination products. ### Which goes on first, sunscreen or bug spray? Sunscreen first, then bug spray. The [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html)'s mosquito bite prevention page puts it in one line: if you are using sunscreen, apply sunscreen first and insect repellent second. The CDC Yellow Book tells travelers the same thing: in general, use separate products, apply sunscreen first, and then apply the repellent. The American Academy of Pediatrics gives the identical order: if using a separate sunscreen product, apply sunscreen first and insect repellent second. The National Pesticide Information Center, NPIC, reports the CDC's advice with one extra step. If you decide to use both, [NPIC](http://npic.orst.edu/factsheets/repellents.html) says, the CDC recommends applying sunscreen first, letting it dry, and then applying an insect repellent over the sunscreen. The drying step is the one that gets left out. A 2015 human urinary study by Yiin and colleagues explains why the order matters. The results suggested that applying oxybenzone sunscreen over DEET on the skin led to significantly higher absorption of DEET. Using both products in the reverse order, sunscreen and then repellent, did not result in significantly more DEET absorption. Their recommendation: should concurrent use of both be necessary, apply sunscreen first and then insect repellent, with a 15 minute interval. ### How long should you wait between the two? Fifteen minutes is the interval the study recommends. The 2015 human urinary study's recommendation is sunscreen first and then insect repellent with a 15 minute interval, should concurrent use of both be necessary. NPIC's report of the CDC advice is less exact but points the same way: sunscreen first, let it dry, then repellent. That number also fits the sunscreen side of the routine. The American Academy of Dermatology says to apply sunscreen to dry skin 15 minutes before going outdoors. So: sunscreen on dry skin, 15 minutes, repellent, out the door. Do not stack them wet. ### Do sunscreen and bug spray cancel each other out? Not evenly. The repellent keeps working; the sunscreen loses some of its rating. On the repellent side, the [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) Yellow Book reports no reduction in repellent activity when a repellent is used with sunscreen. A 2000 study by Murphy and colleagues found that insect repellent had the same efficacy even when sunscreen was applied with it; in the formulations tested, sunscreen did not reduce the efficacy of insect repellent. The sunscreen is the one that suffers. The Yellow Book says limited data show that DEET-containing insect repellents applied over sunscreen decrease the sun protection factor of the sunscreen by one-third. The same 2000 study's abstract describes a previous study that demonstrated a 33.3 percent decrease in sun protection factor when insect repellent and sunscreen were applied sequentially to the skin. The FDA's 2007 request for information reports the same effect, citing a study indicating that separate application of sunscreen followed by DEET resulted in a decrease in SPF after application of the insect repellent. The practical consequence, in the Yellow Book's words: because SPF decreases when a DEET-containing insect repellent is used, travelers might need to reapply sunscreen more frequently. Our [insect repellent for hiking](https://longsleeve.com/blog/insect-repellent-for-hiking) guide walks the trailhead routine in that order, sunscreen first. ### Why is there no good sunscreen and bug spray combo? Because the two ingredients want opposite reapplication schedules, and one product cannot follow both. When the FDA looked at these products in a 2007 request for information, published in the Federal Register, it described the conflict in its own words. A repellent label's reapplication time relates to the effectiveness of the insect repellent portion of the product and not to the sunscreen protection. The directions for sunscreen products, which encourage frequent reapplication, relate to the effectiveness of the sunscreen component of the product and not to the insect repellent component. The same FDA record quotes the EPA's DEET reregistration decision: the agency was concerned about consumer use of products that combine sunscreen and DEET, since directions to reapply sunscreens generously and frequently may promote greater use of DEET than needed for pesticidal efficacy, and thus pose unnecessary exposure to DEET. The FDA also reported that both studies it had on combined products demonstrated increased absorption of DEET and of different sunscreens when the components were combined. That document is a request for information, not a rule. The health bodies are blunter. The CDC Yellow Book says travelers should avoid products that combine sunscreen with repellents, because sunscreen might need to be reapplied more often and in larger amounts than what is needed for the repellent component to provide protection from biting insects. NPIC reports that the CDC does not recommend products that have both sunscreen and an insect repellent, and gives the reason plainly: many repellents work for many hours, sunscreen may need to be used more often than a repellent, so combined products may not be used as often as they should be for sun protection. The American Academy of Dermatology says sunscreen with insect repellent is not a product the AAD recommends, and tells people to purchase and apply each product separately, since sunscreens need to be applied generously and often while insect repellent should be used sparingly and much less frequently. The [American Academy of Pediatrics](https://www.aap.org/en/patient-care/environmental-health/promoting-healthy-environments-for-children/insect-repellents/) tells families to avoid products that combine repellents with sunscreen, and its HealthyChildren.org site warns that applying such a product may expose your child to too much insect repellent. ### Does it matter whether the repellent is a lotion or a spray? In the study that measured it, yes, by a wide margin, with two caveats attached: the study was in vitro, and the repellent was DEET. Gu and colleagues, in a 2005 in vitro study, tested five commercially available products: a repellent spray, [a repellent lotion](https://longsleeve.com/blog/picaridin-lotion-vs-spray), a sunscreen lotion, and two combined repellent and sunscreen lotions. Penetration of DEET from the repellent spray increased by 1640 percent, and from the repellent lotion by 282 percent, when the sunscreen lotion was applied concurrently. Those numbers do not tell you what happens on a person's arm, because the test was in vitro, and nothing about picaridin, because the products contained DEET. What they do show is that the form of the repellent changed the size of the effect under the same sunscreen in the same test. NPIC states the general point without numbers. Mixing an insect repellent with sunscreen can affect how your skin absorbs both products, and using both can increase repellent absorption through skin. ### What about picaridin and sunscreen? In the studies below, picaridin is the repellent and oxybenzone is the sunscreen, and nothing in this piece measures sun protection from picaridin. The picaridin evidence is about skin absorption, from two places. The first is a 2010 in vitro study by Chen and colleagues, run across human epidermis, which found that transdermal permeation of picaridin was significantly lower than that of DEET, both alone and in combination with oxybenzone. Concurrent use of picaridin and oxybenzone resulted in either no changes or suppression of transdermal permeation of picaridin and oxybenzone, which the authors note was different from concurrent use of DEET and oxybenzone, where a synergistic permeation enhancement was observed. The authors concluded from their comparative study that picaridin would be a better candidate for concurrent use with sunscreen preparations in terms of minimizing percutaneous permeation of the chemicals. The second is a 2016 dermatology review by Rodriguez and Maibach, which states that picaridin used simultaneously with sunscreen may decrease percutaneous absorption of both compounds, while combined use of DEET and sunscreen results in significantly higher absorption of both compounds. Those are absorption results reported by one in vitro study and one review, not a claim about any product. On the SPF question, the picaridin file is empty: we could not find a published test of a picaridin repellent's effect on SPF, so the one-third figure above stays a DEET figure. Our [picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet) comparison has the fuller picture. ### How do you use sunscreen and repellent on kids? Same order, separate products, and a lighter hand with the repellent. The American Academy of Pediatrics tells clinicians to advise families to avoid products that combine repellents with sunscreen and, if using a separate sunscreen product, to apply sunscreen first and insect repellent second. It also says to use just enough repellent to cover clothing and exposed skin, because using more does not make the repellent more effective. The AAP's HealthyChildren.org site spells out the combo problem for parents. Its sunscreen interval is every 2 hours while in the sun, and after swimming or sweating; applying a combination product on that schedule may expose your child to too much insect repellent. For ages, amounts and the rest of the routine for children, see our [mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids) guide. ### How often should you reapply each one? Sunscreen gets reapplied often. Repellent does not. The [FDA](https://www.fda.gov/drugs/understanding-over-counter-medicines/sunscreen-how-help-protect-your-skin-sun) says to reapply sunscreen at least every two hours, and more often if you are sweating or swimming. The American Academy of Dermatology says the same: when outdoors, reapply sunscreen approximately every two hours, or after swimming or sweating, according to the directions on the bottle. Repellent runs on the label, not the clock. The CDC Yellow Book's rule is that regardless of the product used, if you start getting bitten, reapply, but not more often than the label allows. The [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively)'s guidance is to apply and reapply according to the label instructions; its exact words: "Don't overuse the products, but be sure to apply the amount of repellent indicated by the label." The Yellow Book adds that heavy application and saturation are generally unnecessary for effectiveness; use just enough to cover exposed skin or clothing. And the EPA says never to use repellents over cuts, wounds or irritated skin. Reapplying repellent every time the sunscreen goes back on is how people end up past the label. Our [how long does picaridin last](https://longsleeve.com/blog/how-long-does-picaridin-last) piece covers the duration side. None of this is medical advice. If you are choosing repellent and sunscreen for a baby, or you have a skin condition, ask a pediatrician or clinician what to use. ### Common questions **Can you put sunscreen on after bug spray?** You can, but the order has been tested and it loses. A 2015 human urinary study reported results suggesting that applying oxybenzone sunscreen over DEET led to significantly higher absorption of DEET, while the reverse order did not add significant extra absorption. NPIC reports the CDC's order: sunscreen first, let it dry, then repellent over it. Do it that way round next time. **Is there a sunscreen and bug spray combo?** Such products exist, but the CDC Yellow Book says travelers should avoid products that combine sunscreen with repellents, and the American Academy of Dermatology says sunscreen with insect repellent is not a product it recommends. The FDA's 2007 request for information named the reason: a repellent's reapplication time relates to the repellent portion of the product, not to the sunscreen protection. **Do sunscreen and bug spray cancel each other out?** Not evenly. The CDC Yellow Book reports no reduction in repellent activity when repellent is used with sunscreen, but says limited data show DEET-containing repellents applied over sunscreen decrease the sunscreen's SPF by one-third. The repellent keeps working; the sunscreen needs reapplying more often. That figure is a DEET figure; we found no picaridin SPF test. **Is picaridin a sunscreen?** In the picaridin studies this piece cites, picaridin is the repellent and oxybenzone is the sunscreen, and nothing here measures sun protection from picaridin. The research on picaridin and sunscreen is about skin absorption: a 2010 in vitro human epidermis study found picaridin permeation significantly lower than DEET's, alone and with oxybenzone, and concurrent picaridin and oxybenzone use gave no change or suppression of permeation. Those are reported study results, not a product claim. **Can I apply repellent directly on top of sunscreen?** Yes, once the sunscreen has dried. NPIC reports that the CDC recommends applying sunscreen first, letting it dry, and then applying an insect repellent over the sunscreen. The 2015 human urinary study that tested the order recommends a 15 minute interval between sunscreen and repellent. Sunscreen on dry skin, 15 minutes, then repellent. ### About Longsleeve Longsleeve is an EPA-registered [picaridin lotion](https://longsleeve.com/ingredients) (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. Its label directions say to apply evenly to skin in a thin layer, no more than two applications a day, and not to apply to excessively sunburned skin, which is why it cannot ride a sunscreen's two-hour schedule. ### Related reading - [Picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet). The two actives compared, side by side. - [Mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). Ages and application for children. - [How long does picaridin last](https://longsleeve.com/blog/how-long-does-picaridin-last). Duration and reapplication. - [Insect repellent for hiking](https://longsleeve.com/blog/insect-repellent-for-hiking). The trailhead routine, sunscreen first. - [Does Bug Spray Expire? What EPA's Label Rules Actually Require](https://longsleeve.com/blog/does-bug-spray-expire). What EPA's label rules actually require, plus heat, freezing and disposal. - [Can You Put Bug Spray on Your Face? Yes, Hands First, and Here Is Why the Label Says So](https://longsleeve.com/blog/bug-spray-on-face). Hands first, and what to do if it gets in your eyes. - [Bug Spray on Clothes or Skin? What Goes Where, What DEET Does to Synthetics, and How to Wash It Out](https://longsleeve.com/blog/bug-spray-on-clothes). What DEET does to synthetics, and how to wash it out. - [Should You Wash Off Bug Spray? What the Label Says About Bedtime, Hikes, and Kids](https://longsleeve.com/blog/wash-off-bug-spray). Before bed, after the hike, and on kids. ### Sources 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC Yellow Book, Mosquitoes, Ticks and Other Arthropods. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. National Pesticide Information Center, Insect Repellents. [http://npic.orst.edu/factsheets/repellents.html](http://npic.orst.edu/factsheets/repellents.html) 1. American Academy of Pediatrics, Insect Repellents. [https://www.aap.org/en/patient-care/environmental-health/promoting-healthy-environments-for-children/insect-repellents/](https://www.aap.org/en/patient-care/environmental-health/promoting-healthy-environments-for-children/insect-repellents/) 1. Yiin LM, Tian JN, Hung CC, Environ Sci Pollut Res Int 2015;22(9):7062-70 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/25491253/](https://pubmed.ncbi.nlm.nih.gov/25491253/) 1. American Academy of Dermatology, Sunscreen FAQs. [https://www.aad.org/public/everyday-care/sun-protection/sunscreen-patients/sunscreen-faqs](https://www.aad.org/public/everyday-care/sun-protection/sunscreen-patients/sunscreen-faqs) 1. Murphy ME, Montemarano AD, Debboun M, Gupta R, J Am Acad Dermatol 2000;43(2 Pt 1):219-22 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/10906641/](https://pubmed.ncbi.nlm.nih.gov/10906641/) 1. FDA, Insect Repellent-Sunscreen Drug Products for Over-the-Counter Human Use, Request for Information, Federal Register 72 FR 7941, February 22, 2007. [https://www.federalregister.gov/documents/2007/02/22/E7-2890/insect-repellent-sunscreen-drug-products-for-over-the-counter-human-use-request-for-information-and](https://www.federalregister.gov/documents/2007/02/22/E7-2890/insect-repellent-sunscreen-drug-products-for-over-the-counter-human-use-request-for-information-and) 1. American Academy of Pediatrics, HealthyChildren.org, Insect Repellents. [https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx](https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx) 1. Gu X, Wang T, Collins DM, Kasichayanula S, Burczynski FJ, Br J Dermatol 2005;152(6):1263-7 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/15948991/](https://pubmed.ncbi.nlm.nih.gov/15948991/) 1. Chen T, Burczynski FJ, Miller DW, Gu X, Pharmazie 2010;65(11):835-9 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/21155391/](https://pubmed.ncbi.nlm.nih.gov/21155391/) 1. Rodriguez J, Maibach HI, J Dermatolog Treat 2016;27(1):11-8 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/26811157/](https://pubmed.ncbi.nlm.nih.gov/26811157/) 1. FDA, Sunscreen: How to Help Protect Your Skin from the Sun. [https://www.fda.gov/drugs/understanding-over-counter-medicines/sunscreen-how-help-protect-your-skin-sun](https://www.fda.gov/drugs/understanding-over-counter-medicines/sunscreen-how-help-protect-your-skin-sun) 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) Last reviewed 2026-09-09 · every claim on this page is sourced above ## Bug Spray on Clothes or Skin? Stains, Synthetics, and Fabric Time URL: https://longsleeve.com/blog/bug-spray-on-clothes > Both, never under clothing. DEET is a plasticizer that can hurt synthetics, not cotton or wool. Permethrin is the product made for fabric. How to wash it out. Source: https://longsleeve.com/blog/bug-spray-on-clothes By [Andrew Rothaus](https://longsleeve.com/about), Founder · September 9, 2026 **Short answer:** Both, and never in between. EPA says to apply repellents only to exposed skin and/or clothing, and not under clothing. NPIC calls DEET a plasticizer that can damage certain synthetic or treated fabrics, and says it does not damage cotton or wool. Permethrin is the repellent used to factory-treat clothing. Wash treated clothing before wearing it again. ### Do you put bug spray on skin or on clothes? Both, as long as the clothing is on the outside. EPA's guidance on using repellents is to apply them only to exposed skin and/or clothing, and not to use them under clothing. The [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html)'s Yellow Book says it in its own words: apply repellents only to exposed skin or clothing, as directed on the product label, and do not apply to skin covered by clothing. The CDC's mosquito-bite prevention page: do not apply repellent on the skin under clothing. The product label carries the same two directions. [EPA](https://www.epa.gov/insect-repellents/deet)'s DEET page lists them: use just enough repellent to cover exposed skin and/or clothing, and do not use under clothing. NPIC's DEET fact sheet gives the reason for the second one. People have had adverse reactions to DEET when they applied it to skin that was under clothing, and when they applied it to parts of the body that contacted other skin surfaces. NPIC lists the human body, clothing and headgear among the sites where DEET repellents are used, and the label rules out the skin underneath. The amount is a thin film. [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) says to read the label and be sure you understand how much to apply; the CDC's guidance is to use just enough repellent to cover exposed skin or clothing. The CDC says heavy application and saturation are generally unnecessary for effectiveness, and that if biting insects do not respond to a thin film of repellent, you apply a bit more. Picaridin follows the same skin-or-clothing rule. NPIC says picaridin can be used on human skin or clothing to repel mosquitoes, biting flies, ticks, fleas and chiggers, and NPIC's technical fact sheet states that picaridin is registered for use on the human body and clothing. [EPA](https://www.epa.gov/insect-repellents/repellent-treated-clothing) also registers products consumers can spray on clothing to repel mosquitoes and ticks; the ones currently available contain DEET, permethrin or picaridin. The [trailhead routine](https://longsleeve.com/blog/insect-repellent-for-hiking) is the same whichever active you carry: repellent on the skin that shows, repellent on the outside of what covers the rest, nothing underneath. ### Does bug spray stain clothes, or does it damage them? The evidence is about damage, not dye. The primary source, the National Pesticide Information Center's DEET technical fact sheet, says nothing about color. What [NPIC](http://npic.orst.edu/factsheets/archive/DEETtech.html) says is that DEET, a plasticizer, can damage certain rubber, plastic, vinyl or elastic materials, and it names them: contact lenses, eyeglass frames and lenses, watch crystals, combs, painted and varnished surfaces, and certain synthetic or treated fabrics. The same fact sheet gives the other half: DEET does not damage natural fibers including cotton and wool. A cotton T-shirt or a wool sock is not on NPIC's list. Anything elastic, and anything synthetic or treated, sits in the group NPIC says DEET can damage. NPIC's word is "certain," so not every synthetic will react, but the category is the warning. If something synthetic came out of a DEET summer feeling or fitting different, the plasticizer note is the explanation the sources support. Picaridin's fabric record is thinner, and we will not pad it. [NPIC](http://npic.orst.edu/factsheets/archive/Picaridintech.pdf)'s picaridin technical fact sheet reports that picaridin applied to cloth deterred insects from biting through the cloth to the skin, says insects that encounter treated skin or clothing move away from the chemical and do not feed, and lists picaridin as not soluble in water. No approved source we could find says whether picaridin stains or damages any fabric, so this post does not say it either. Neither NPIC sheet reports on visible discoloration by either active. The materials comparison lives in our [picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet) post. ### How do you get bug spray out of clothes? The American Cleaning Institute's answer is pretreat, wash hot, check before the dryer. The American Cleaning Institute's starting point: most commercially available bug sprays and sunscreens do wash out relatively easily. First, the American Cleaning Institute says, pretreat the stains with a prewash stain remover, then launder using the hottest water that is safe for the fabric. The last step is the one that saves the shirt: the American Cleaning Institute says to check that the stains are gone before you put the garment in the dryer, because heat could set stains that have not washed out. The label sets the timing. EPA's DEET page carries the direction to [wash treated clothing before wearing it again](https://longsleeve.com/blog/wash-off-bug-spray), so the wash is a label direction, not only a stain fix, and it applies whether or not you can see anything on the shirt. ### How long does bug spray last on fabric? Nobody we cite publishes a number, and this post will not make one up. The hours on a repellent label describe skin. [EPA](https://www.epa.gov/insect-repellents/repellency-awareness-graphic)'s repellency awareness graphic identifies the type of pest a product is expected to repel and the amount of time the repellent will be effective, and EPA says the graphic will be available only for skin-applied insect repellent products. EPA's repellent search tool draws the same line: its results include only skin-applied repellent products registered by EPA. Even on skin the figures spread. [EPA](https://www.epa.gov/insect-repellents/find-repellent-right-you) notes that while its technical information is based on scientific testing guidelines and approved study methods, there are variations in the resulting protection times because of differences in the testing conditions. For DEET, EPA says studies in its database indicate DEET repels ticks for about two to ten hours, and mosquitoes from two to twelve hours, depending on the percentage of DEET in the product. That is a skin range, and it is already wide. On fabric, the closest thing to a duration statement is the CDC's Yellow Book, which says clothing treated with repellent products such as DEET provides protection from biting arthropods but will not last through washing and will require more frequent application. The CDC attaches no hours to that sentence. We could not find an EPA, CDC or NPIC figure for how long a skin repellent keeps working on a shirt, and we will not derive one from skin data. Reapply on the label's schedule, treat a wash as a reset, and if you want fabric that stays treated across washes, that is a different product. ### Which repellent is actually made for clothing? If you want fabric that stays treated, the product is permethrin, and our [permethrin clothing guide](https://longsleeve.com/blog/permethrin-clothing) covers it in depth. EPA says the only insect repellent currently used for factory treatment of clothing is permethrin. The CDC's Yellow Book says that at a concentration of 0.5 percent, permethrin-treated clothing repels and kills chiggers, ticks, mosquitoes, and other biting and nuisance arthropods, and that travelers can treat clothing, hats, shoes, mosquito nets, outerwear and camping gear with permethrin for added protection. The wash story is the opposite of DEET's. The CDC says permethrin-treated materials retain repellency or insecticidal activity after repeated launderings but should be retreated as described on the product label to provide continued protection, and EPA adds that small amounts of permethrin can come off in the wash, as shown by available scientific studies. Never on skin. The CDC says permethrin should never be applied to the skin but only to clothing, mosquito nets or other fabrics as directed on the product label. A treated shirt also covers only what it covers: EPA says only the skin surface covered with factory-treated clothing is protected from the pests listed on the label, and that other exposed parts of the body should be treated with an insect repellent labeled for use on human skin. That pairing, permethrin on the layer and a skin repellent on the rest, is the [two-layer system](https://longsleeve.com/blog/permethrin-picaridin-system). Two label details, and one number to distrust. EPA says permethrin products used for factory treatment of clothing or as spray-ons for clothing are not to be applied to certain clothing such as underwear, and that the label instructs consumers to wash permethrin-treated clothing separately from non-treated clothing. The number: a 2019 study in Parasites & Vectors (Gopalakrishnan et al.) reports that, in contrast to the manufacturer's claim of 70 washings, bioefficacy rapidly declined after four washings in its tests, and the authors write that the rigorous washing and drying methods adopted in tropical regions might lead to a higher loss of permethrin than reported in standard laboratory conditions. The 70 is a manufacturer's number, the four came from one washing method, and neither one is an EPA figure or carries over to a machine-washed shirt. ### Do you have to wash clothes after spraying them? Yes, for skin repellents. EPA's general guidance is that after returning indoors you wash treated skin and clothes with soap and water; for children, EPA's wording is to wash your child's treated skin and clothes with soap and water, or bathe. The DEET label directions cover both surfaces: after returning indoors, wash treated skin with soap and water, and wash treated clothing before wearing it again. Clothing meant to stay treated follows its own label instead. The CDC's Yellow Book tells travelers to follow instructions on the product label for handling repellent-treated clothing. For permethrin, EPA says the label instructs consumers to wash permethrin-treated clothing separately from non-treated clothing, because those products are not to be applied to certain clothing such as underwear. So the rule splits by product: a skin repellent gets washed out before the next wear; a permethrin-treated shirt gets washed the way its own tag says, apart from the rest of the load, and retreated as its label describes. ### Common questions **Will bug spray stains come out?** Usually, according to the American Cleaning Institute. The American Cleaning Institute says most commercially available bug sprays and sunscreens do wash out relatively easily. The American Cleaning Institute's steps: pretreat the stains with a prewash stain remover, launder using the hottest water that is safe for the fabric, then check that the stains are gone before the garment goes in the dryer, because the American Cleaning Institute warns that heat could set stains that have not washed out. **Does DEET permanently stain clothes?** The primary source does not talk about stains; it talks about damage. NPIC says DEET, a plasticizer, can damage certain rubber, plastic, vinyl or elastic materials, including certain synthetic or treated fabrics. NPIC also says DEET does not damage natural fibers including cotton and wool. We found no approved source on permanent discoloration, so treat a mark as a stain to wash out and a changed synthetic as plasticizer damage. **Can you spray DEET on clothes?** Yes, on the outside. EPA says to apply repellents only to exposed skin and/or clothing, and the DEET label direction is do not use under clothing. Check what the garment is made of first. NPIC says DEET can damage certain synthetic or treated fabrics and certain elastic materials, and that it does not damage natural fibers including cotton and wool. Cotton and wool take it; synthetics and elastic are the ones to think about. **Does bug spray on clothes work?** Yes, with limits. The CDC's Yellow Book says clothing treated with repellent products such as DEET provides protection from biting arthropods but will not last through washing and will require more frequent application. NPIC reports that picaridin applied to cloth deterred insects from biting through the cloth to the skin. For fabric meant to stay treated, EPA says permethrin is the only insect repellent currently used for factory treatment of clothing. **How long does bug spray last on fabric?** No agency we cite publishes an hours figure for a skin repellent on fabric, and we will not invent one. EPA's repellency awareness graphic, the protection-time mark on labels, is available only for skin-applied insect repellent products, so label hours describe skin. On fabric, the CDC says clothing treated with products such as DEET will not last through washing and will require more frequent application. Reapply per the label, and treat a wash as a reset. ### About Longsleeve Longsleeve is an EPA-registered [picaridin lotion](https://longsleeve.com/ingredients) (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. Its approved label claims include that it does not damage plastic, and its directions say to apply evenly to skin in a thin layer and not under clothing. ### Related reading - [Permethrin for clothing](https://longsleeve.com/blog/permethrin-clothing). The fabric treatment in depth: what to treat, how, and what the label says about washing. - [The permethrin and picaridin system](https://longsleeve.com/blog/permethrin-picaridin-system). Permethrin on the layer, a skin repellent on the rest. - [Picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet). The two actives side by side, including the materials question. - [Insect repellent for hiking](https://longsleeve.com/blog/insect-repellent-for-hiking). What to treat before you leave the trailhead. - [Does Bug Spray Expire? What EPA's Label Rules Actually Require](https://longsleeve.com/blog/does-bug-spray-expire). What EPA's label rules actually require, plus heat, freezing and disposal. - [Bug Spray and Sunscreen: Which Goes On First, How Long to Wait, and Why Not a Combo](https://longsleeve.com/blog/bug-spray-and-sunscreen). Sunscreen first, then repellent, and why not a combo. - [Picaridin Lotion vs Spray: Which Form Actually Works Better?](https://longsleeve.com/blog/picaridin-lotion-vs-spray). What actually decides how long you are protected. - [Can You Put Bug Spray on Your Face? Yes, Hands First, and Here Is Why the Label Says So](https://longsleeve.com/blog/bug-spray-on-face). Hands first, and what to do if it gets in your eyes. ### Sources 1. US EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. NPIC, DEET Technical Fact Sheet. [http://npic.orst.edu/factsheets/archive/DEETtech.html](http://npic.orst.edu/factsheets/archive/DEETtech.html) 1. US EPA, Repellent-Treated Clothing. [https://www.epa.gov/insect-repellents/repellent-treated-clothing](https://www.epa.gov/insect-repellents/repellent-treated-clothing) 1. US EPA, DEET. [https://www.epa.gov/insect-repellents/deet](https://www.epa.gov/insect-repellents/deet) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. NPIC, DEET General Fact Sheet. [http://npic.orst.edu/factsheets/DEETgen.html](http://npic.orst.edu/factsheets/DEETgen.html) 1. NPIC, Picaridin General Fact Sheet. [http://npic.orst.edu/factsheets/PicaridinGen.html](http://npic.orst.edu/factsheets/PicaridinGen.html) 1. NPIC, Picaridin Technical Fact Sheet. [http://npic.orst.edu/factsheets/archive/Picaridintech.pdf](http://npic.orst.edu/factsheets/archive/Picaridintech.pdf) 1. American Cleaning Institute, Ask ACI: Bug Spray and Sunscreen on Clothes. [https://www.cleaninginstitute.org/cleaning-tips/clean-home/ask-aci/ask-aci-bug-spray-and-sunscreen-clothes](https://www.cleaninginstitute.org/cleaning-tips/clean-home/ask-aci/ask-aci-bug-spray-and-sunscreen-clothes) 1. US EPA, Repellency Awareness Graphic. [https://www.epa.gov/insect-repellents/repellency-awareness-graphic](https://www.epa.gov/insect-repellents/repellency-awareness-graphic) 1. US EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. Gopalakrishnan R et al., Parasites & Vectors, 2019. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6664487/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6664487/) Last reviewed 2026-09-09 · every claim on this page is sourced above ## Can You Put Bug Spray on Your Face? Hands First, and Why URL: https://longsleeve.com/blog/bug-spray-on-face > Yes, but never sprayed at your face. Hands first, then face and neck, sparingly at the ears. Why the eye warning exists, eye first aid, and a child's face. Source: https://longsleeve.com/blog/bug-spray-on-face By [Andrew Rothaus](https://longsleeve.com/about), Founder · September 9, 2026 **Short answer:** Yes, but never sprayed at your face. EPA says to spray on your hands first and then apply to your face, not near your eyes and mouth, and sparingly around the ears. The Longsleeve label gives [the same technique for a lotion](https://longsleeve.com/blog/picaridin-lotion-vs-spray): small amounts in your palms first, then face and neck, avoiding your eyes. ### Why are you told not to spray it at your face? Because of your eyes. [Health Canada](https://www.canada.ca/en/health-canada/services/about-pesticides/insect-repellents.html)'s insect repellent guidance says it in one line: do not spray directly onto your face because you may get it in your eyes. EPA's version of the rule is the instruction itself: spray on hands first and then apply to face. The National Pesticide Information Center (NPIC) spells out the hazard. [NPIC](https://npic.orst.edu/factsheets/DEETgen.html)'s general fact sheet on DEET says that when products containing DEET get into the eyes, they may cause irritation, pain and watery eyes. NPIC's technical fact sheet on DEET says reported symptoms were most frequently associated with ocular exposure, with effects including eye irritation or pain and excess tearing, and describes 24-hour ocular exposure studies in rabbits with technical grade DEET: researchers observed slight to moderate corneal opacity, slight iritis, and moderate to severe conjunctivitis, and symptoms generally cleared within five to seven days. Picaridin has its own NPIC sheets. [NPIC](https://npic.orst.edu/factsheets/PicaridinGen.html)'s general fact sheet on picaridin says that if picaridin gets into someone's eyes, it may cause irritation. NPIC's technical fact sheet on picaridin says picaridin is not considered a skin irritant and is not a sensitizer, but it can cause slight to moderate eye irritation. The warning printed on the bottle comes from a rulebook most people never see. EPA's Label Review Manual sets the standard wording EPA requires on pesticide labels. One entry defines an eye irritation level as corneal involvement or other eye irritation clearing in 8 to 21 days. Another gives the precautionary statement: "Causes substantial but temporary eye injury. Do not get in eyes or on clothing." The Longsleeve label carries that statement in its own form: "Causes substantial but temporary eye injury. Do not get in eyes." That sentence stops people at the shelf. It is the wording EPA's manual requires for that eye irritation level, and the technique in the next section is how you keep the product away from your eyes. ### How do you put bug spray on your face? Hands first, then face, then [wash your hands](https://longsleeve.com/blog/wash-off-bug-spray). That is the entire technique. [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively)'s wording: when using sprays, do not spray directly into face; spray on hands first and then apply to face. EPA also says not to apply near eyes and mouth, and to apply sparingly around ears. Longsleeve is a lotion, and its label says it this way: apply on face by first spreading small amounts in palms of hands and spreading on face and neck, avoiding your eyes. The label also says to apply sparingly around ears. Small amounts is the operative phrase. You are spreading a thin film across a face, and the palms are how the label tells you to place it. Two more lines belong in the routine. EPA says never to use repellents over cuts, wounds, or irritated skin, and the Longsleeve label says to avoid contact with lips, cuts, wounds, or irritated skin. Then wash your hands. The [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) Yellow Book says to wash hands after application to avoid accidental ingestion or exposure to eyes. ### What if bug spray gets in your eyes? Rinse them with water, right away. Health Canada's guidance is that if you have accidentally sprayed repellent in your eyes, you rinse them immediately with water. The first aid wording [EPA](https://www.epa.gov/sites/default/files/2018-04/documents/chap-07-mar-2018.pdf) requires on pesticide labels is more specific: hold eye open and rinse slowly and gently with water for 15 to 20 minutes, and if you wear contact lenses, remove them after the first 5 minutes, then continue rinsing. The Longsleeve label's first aid line for eyes reads: hold eye open and rinse gently with water. Poison Control, meaning the National Capital Poison Center, describes what to expect. Poison Control says that when an insect repellent gets in the eyes, irritation and redness are common, serious eye injury is not likely, the eyes should be rinsed immediately, contact lenses should come out, and you should use lots of room temperature water. For a child, Poison Control's technique is to pour water onto the bridge of the nose and let it gently run into the eyes, and to encourage blinking. Then call. NPIC's fact sheet says to contact the Poison Control Center at 800-222-1222. Save the number in your phone now. ### Can you put bug spray on a child's face? Yes, through your own hands. The [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html)'s instruction is to apply repellent onto your hands and then apply to a child's face. The CDC Yellow Book adds that children should not handle repellents; instead, adults should apply repellent to their own hands first and then gently spread product on the child's exposed skin, avoiding the child's hands. The American Academy of Pediatrics says the same: spray a little on your hands first and then rub it on your child's face, avoiding the eyes and mouth. EPA says that because children frequently put their hands in their eyes and mouths, it recommends that all repellent products carry precautionary statements about children on their labels, among them: do not allow children to handle this product, and do not apply to children's hands. The American Academy of Pediatrics agrees: no repellent on children's hands, because they may put their hands, and the insect repellent, in their mouth and eyes. The CDC's list of places not to apply repellent on a child is hands, eyes, mouth, cuts, or irritated skin. The Longsleeve label follows that chain: to apply to a child's face and neck, apply the product into your hands and apply to the child; do not apply to their hands; take care to avoid mouth and eyes and apply sparingly around ears; do not allow children to handle the product. For ages and infants, read our guide to [mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). ### Sprays, lotions, wipes and sticks: does the format matter for the face? It matters in one way: whether the product can reach your eyes on the way to your face. EPA's rule is written about sprays: when using sprays, do not spray directly into face; spray on hands first and then apply to face. Health Canada gives the reason, that you may get it in your eyes. The hazard is a spray aimed at a face; the fix is your hands. [NPIC](https://npic.orst.edu/factsheets/archive/DEETtech.pdf)'s technical fact sheet on DEET lists that repellent's formulations as liquids, pressurized liquids, lotions, sticks, foams, and impregnated materials such as towelettes. A lotion, a stick and a towelette do not leave their containers as a mist, so the product reaches your face without being in the air in front of it. That is a structural point, and the only one we will make; the agencies write about technique, and so do we. The other format question people ask is skin or clothes. EPA says to apply repellents only to exposed skin and/or clothing, and [not to use them under clothing](https://longsleeve.com/blog/bug-spray-on-clothes). On the face, the answer is a technique rather than a format. Read your own product's label for what it allows. ### How long does it stay on your skin, and when do you wash it off? For as long as your product's label states, minus whatever the day takes off it, and you wash it off when you come indoors. This page will not give you an hours-on-skin number. Read the one on your own product's label, and read it knowing what [EPA](https://www.epa.gov/insect-repellents/find-repellent-right-you) says about the published times: there are variations in the resulting protection times because of differences in the testing conditions. What shortens it is ordinary. The CDC Yellow Book says product efficacy and duration of protection are markedly affected by ambient temperature, level of activity, amount of perspiration, exposure to water, being rubbed off during activities, and other factors. On a face that is sweat, a swim, a towel, and a hand across the forehead. For picaridin specifically, read [how long picaridin lasts](https://longsleeve.com/blog/how-long-does-picaridin-last). Then take it off. EPA's instruction is that after returning indoors, you wash treated skin and clothes with soap and water. NPIC's DEET fact sheet says people who have left DEET products on their skin for extended periods of time have experienced irritation, redness, a rash, and swelling. NPIC's picaridin fact sheet says some people have had skin irritation from using products containing picaridin, although this is very uncommon. Soap, water, done. ### Common questions **What happens if you put bug spray on your skin?** Used as directed, the CDC says EPA-registered insect repellents are proven safe and effective, even for pregnant and breastfeeding women. NPIC reports that people who have left DEET products on their skin for extended periods of time have experienced irritation, redness, a rash, and swelling, and that some people have had skin irritation from products containing picaridin, although this is very uncommon. **What bug spray is safe for skin?** The CDC's answer is a category. When used as directed, the CDC says, EPA-registered insect repellents are proven safe and effective, even for pregnant and breastfeeding women. Look for the words EPA-registered on the label and follow the directions printed under them; "used as directed" is half of the CDC's sentence. **Does bug spray go on skin or clothes?** Both, on the outside. EPA says to apply repellents only to exposed skin and/or clothing, and not to use them under clothing. For the face, the rule stays the same whatever surface you started with: when using sprays, EPA says, do not spray directly into face; spray on hands first and then apply to face. **Can you put bug spray on a baby's or child's face?** For a child, yes, through your own hands. The CDC says to apply repellent onto your hands and then apply to a child's face. Age limits are a separate question, and repellent for infants is covered in our guide to mosquito repellent for kids . None of this is medical advice. If an eye exposure does not settle after rinsing, call Poison Control at 800-222-1222 and see a clinician. ### About Longsleeve Longsleeve is an EPA-registered [picaridin lotion](https://longsleeve.com/ingredients) (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. Its label directions for the face: spread small amounts in the palms of the hands first, then on face and neck, avoiding the eyes, sparingly around the ears; for a child, apply to your own hands and then to the child, never to the child's hands. ### Related reading - [Mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). Ages, actives, and the alternatives for infants. - [How long does picaridin last](https://longsleeve.com/blog/how-long-does-picaridin-last). Duration in depth, and what shortens it. - [Picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet). The two actives side by side, on the axes the evidence supports. - [Ingredients](https://longsleeve.com/ingredients). The nine disclosed ingredients, in full. - [Does Bug Spray Expire? What EPA's Label Rules Actually Require](https://longsleeve.com/blog/does-bug-spray-expire). What EPA's label rules actually require, plus heat, freezing and disposal. - [Bug Spray and Sunscreen: Which Goes On First, How Long to Wait, and Why Not a Combo](https://longsleeve.com/blog/bug-spray-and-sunscreen). Sunscreen first, then repellent, and why not a combo. ### Sources 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. Health Canada, Insect repellents. [https://www.canada.ca/en/health-canada/services/about-pesticides/insect-repellents.html](https://www.canada.ca/en/health-canada/services/about-pesticides/insect-repellents.html) 1. NPIC, DEET General Fact Sheet. [https://npic.orst.edu/factsheets/DEETgen.html](https://npic.orst.edu/factsheets/DEETgen.html) 1. NPIC, DEET Technical Fact Sheet (PDF). [https://npic.orst.edu/factsheets/archive/DEETtech.pdf](https://npic.orst.edu/factsheets/archive/DEETtech.pdf) 1. NPIC, Picaridin General Fact Sheet. [https://npic.orst.edu/factsheets/PicaridinGen.html](https://npic.orst.edu/factsheets/PicaridinGen.html) 1. NPIC, Picaridin Technical Fact Sheet (PDF). [https://npic.orst.edu/factsheets/archive/Picaridintech.pdf](https://npic.orst.edu/factsheets/archive/Picaridintech.pdf) 1. EPA Label Review Manual, Chapter 7: Precautionary Statements (PDF). [https://www.epa.gov/sites/default/files/2018-04/documents/chap-07-mar-2018.pdf](https://www.epa.gov/sites/default/files/2018-04/documents/chap-07-mar-2018.pdf) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. National Capital Poison Center, Insect Repellent. [https://www.poison.org/articles/insect-repellent](https://www.poison.org/articles/insect-repellent) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. AAP HealthyChildren.org, Insect Repellents. [https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx](https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) Last reviewed 2026-09-09 · every claim on this page is sourced above ## Do Bug Zappers Work on Mosquitoes? What Field Studies Found URL: https://longsleeve.com/blog/bug-zappers > What field studies found about bug zappers and mosquitoes, why ultraviolet light catches mostly non-target insects, and how EPA device rules differ from repellent registration. Source: https://longsleeve.com/blog/bug-zappers By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 16, 2026 No, not for the mosquitoes biting you. In field studies, biting flies were a tiny share of the catch: 31 out of 13,789 insects across one Delaware summer. The Indiana trial that measured biting rates found no reduction. Zappers lure with ultraviolet light. Host-seeking females track carbon dioxide, body odor, and heat. ### What do bug zappers actually kill? The fullest count comes from Frick and Tallamy at the University of Delaware. In the summer of 1994 they recruited six homeowners in suburban Newark who already ran zappers, hung a collection dish under each unit, and identified everything that fell in. All six houses sat within 3 km of water, so biting flies had somewhere nearby to breed. The abstract: "Our survey of insects electrocuted during routine use of electric insect traps revealed only 31 biting flies, a minute proportion (0.22%) of the 13,789 total insects counted." **Short answer:** Field studies do not support bug zappers as a way to reduce mosquito bites. One Delaware summer count found only 31 biting flies among 13,789 insects killed, and an Indiana biting-rate trial found no reduction. Zappers use ultraviolet light, while host-seeking female mosquitoes track cues such as carbon dioxide, odor, and heat. Heinen and colleagues, testing retail electrocutors at the University of Michigan Biological Station, found the same shape twice. In 1999, of 8,309 insects killed by the electrocutors, 31 (0.37 percent) were biting insects. In 2002, of 11,076 insects killed across every device they ran, 98 were biting insects. Both years, midges dominated the catch. ### Did anyone test whether a zapper reduces bites? Yes. A low percentage in the tray could still coexist with fewer bites. Nasci, Harris, and Porter ran that test in South Bend, Indiana and published it in *Mosquito News* in 1983 under a title that gives away the ending: "Failure of an insect electrocuting device to reduce mosquito biting." Six adjacent backyards, eight nights in 1982, two yards with electronic insect killing devices, two with CDC traps, two with nothing. Per the abstract: "Only 3.3% of the 3212 insects killed on an average night were female mosquitoes. Humans in the vicinity of the electrocuting devices were consistently more attractive to mosquitoes than the devices. Even after 11 days of continuous operation, the electrocuting devices failed to reduce the mosquito biting rate." The American Mosquito Control Association summarizes the yard-level evidence in its FAQ: two controlled studies by independent investigators at the University of Notre Dame found mosquitoes made up "merely 4.1% and 6.4% respectively of the daily catch over an entire season," and in both, "there was no significant difference in the number of mosquitoes found in yards with or without bug zappers." A 1998 Illinois trial by Jensen and colleagues counted mosquito landing rates against a UV insect-killing grid baited with 1-octen-3-ol and several other consumer products. The abstract names the winners: "the mosquito coils and the deet-impregnated wrist bands did significantly reduce mosquito landing rates relative to untreated controls." The UV grid is not on that list. ### Why doesn't ultraviolet light pull in host-seeking mosquitoes? Because the cues a host-seeking female follows come off a living body. Writing in *Cell* in 2014, McMeniman and colleagues describe the cue set: "To orient towards hosts, female mosquitoes detect a variety of chemical and physical cues including body odor, CO 2 , moisture, heat, and visual contrast." Exhaled CO 2 , they add, "is often considered to be the most important sensory cue used by these disease vectors to find humans." Ultraviolet light is not on that list. More on those cues in [why mosquitoes bite some people](https://longsleeve.com/blog/why-mosquitoes-bite-some-people). Frick and Tallamy laid out the mechanics. Consumer trap lamps emit a lot of visible light, and lamps like that "are less attractive to mosquitoes than lamps emitting only ultraviolet wavelengths." Beyond that, "many species of mosquitoes are not attracted to light traps at all." They call two reasons perhaps the most important: "carbon dioxide exhaled by homeowners is far more attractive to mosquitoes than are light traps," and "mosquitoes that do move toward traps are rarely killed by electrocution devices." There is a timing problem too. The CDC Yellow Book puts peak biting activity for *Aedes aegypti* and [Aedes albopictus](https://longsleeve.com/blog/asian-tiger-mosquito) at dawn and dusk, while *Culex quinquefasciatus* peaks after sunset, "usually between 10 and 11 p.m." ### Does adding octenol or carbon dioxide fix it? Manufacturers tried. Heinen and colleagues tested electrocutors with and without an octenol lure, alongside propane-burning "eliminator" traps that use carbon dioxide, heat, and octenol instead of light. Octenol on a zapper did not help. Their results table records that octenol "did not effect the numbers of biting insects killed by electrocutors" (0.1 > p > 0.05), while "electrocutors baited with octenol killed more non-biting insects than electrocutors not baited with octenol" (p < 0.001). The bait mostly increased the midge and moth kill. The CO 2 traps were far more selective. Of 69 insects taken by eliminators, 19 (27.5 percent) were biting insects, a significantly higher proportion than the electrocutors managed. The total is the problem: 69 against 11,009 for the electrocutors that year. The AMCA's view of baited traps generally: they "will trap and kill measurable numbers of mosquitoes," yet "the homeowner must still use repellents and practice source reduction methods." ### What else does a zapper do? Frick and Tallamy's traps averaged 445 insects per trap on nights they ran at least two hours. The authors then ran an extrapolation they called speculative: if 4 million traps run 40 nights a summer, that is more than 71 billion nontarget insects a year in the United States. There is also the spray. Urban and Broce, in *Current Microbiology* in 2000, loaded house flies with bacteria or a phage and electrocuted them in a room: "Sprayed flies released one of every 10,000 of the added bacteria or viruses." Their conclusion kept the qualifier: the results "suggest EITs could play a role in the spread of infectious disease agents, but the potential is influenced by the insect's route of contamination." Colorado State University Extension: zappers "should never be used near areas where food is prepared or consumed." ### Why doesn't the EPA make manufacturers prove these work? Because under federal pesticide law a zapper is a device, not a pesticide. The [EPA](https://www.epa.gov/pesticides/pesticide-devices-guide-consumers) names the category: "Products claiming to control pests via electromagnetic and/or electrical means (e.g., ultrasonic insect and rodent repellers, hand-held bug zappers, electric flea combs) are devices, provided that ... the product is not sold with a pesticidal substance." And: "For products regulated as devices, there is no required premarket review." Registered pesticide products, by contrast, "undergo a thorough review of data supporting the registration, including product performance (efficacy) studies." Same rule, same reason [ultrasonic repellers](https://longsleeve.com/blog/ultrasonic-repellers) stay on shelves. ### What do university extension services say? - **Penn State Extension:** "Avoid bug zappers. While these devices may appear to have value, research has shown that they kill few mosquitoes. They kill many beneficial insect species that can benefit insect control around your home and yard." - **University of Maryland Extension:** "Do NOT use bug 'zappers', mosquito traps, or plants marketed as having mosquito repelling properties." (More on [repellent plants](https://longsleeve.com/blog/citronella-and-plant-repellents).) - **Rutgers Center for Vector Biology:** "Comparison trapping has also shown no significant difference in mosquito populations in yards with and without the traps." - **Iowa State University Extension** on the Delaware data: "Pests, and especially biting pests, do not end up in the traps." - **University of Florida IFAS** reported in 1997 that in tests at its Florida Medical Entomology Laboratory, "Out of some 10,000 insects destroyed by one bug zapper during a one-night test period, only eight were mosquitoes." ### What does the CDC recommend for mosquito bites? The [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html) recommends EPA-registered insect repellents with one of six active ingredients: DEET, picaridin (known as KBR 3023 and icaridin outside the United States), IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone. It adds: "Look for an EPA registration number (EPA Reg. No.) on the insect repellent product label. This registration number means the company provided EPA with technical information on the effectiveness of the product." Alongside that: loose-fitting long-sleeved shirts and pants, [permethrin-treated clothing and gear](https://longsleeve.com/blog/permethrin-clothing), window and door screens, air conditioning where available, and once a week emptying and scrubbing anything that holds water, which our guide to [standing water control](https://longsleeve.com/blog/standing-water-mosquito-control) covers. For the yard, the CDC points to larvicides for water that cannot be dumped and outdoor adulticides for the "dark, humid areas" where adults rest. ### How solid is this evidence? Solid on catch composition, thinner on yard-level bite counts, and the authors say so themselves. Frick and Tallamy wrote: "Since we did not independently measure mosquito populations in our study sites we cannot definitively conclude that the zappers used in our study were ineffective mosquito killers." Heinen and colleagues flagged the same gap: "On the evenings sampled, the human collectors were regularly bitten by both mosquitoes and blackflies, suggesting their presence." The mosquitoes were present. They were biting the collectors even as the grids caught almost none. Most of this work is also old: Delaware 1994, Indiana 1982, Michigan 1999 and 2002. We found no recent peer-reviewed field trial overturning it. If a bite reaction worries you, or you develop a fever or rash after being bitten, talk to a clinician. Our [bite treatment guide](https://longsleeve.com/blog/mosquito-bite-treatment) covers ordinary cases. ### Common questions **Do bug zappers attract more mosquitoes into my yard?** We could not verify that with a controlled measurement. The studies we retrieved counted what died in the tray and what bit the people standing nearby, not whether more mosquitoes arrived. They did find the devices failed to reduce biting. **Do zappers work on no-see-ums, black flies, or ticks?** The Delaware study counted 12 female biting midges and one black fly among its 13,789 insects. As for ticks, the CDC says they "can't fly or jump," so a flying-insect light trap has no bearing on them. See when tick season runs and prevention instead. **What about the propane CO2 traps?** More selective than a zapper, but the Michigan eliminators caught only 69 insects in total. The AMCA cautions "against putting too much faith in traps as your sole means of control." ### Where Longsleeve fits Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with [nine disclosed ingredients](https://longsleeve.com/ingredients). ### Related reading - [Natural Bug Repellents: What the Evidence Supports](https://longsleeve.com/blog/natural-repellents). Registered plant-derived actives, the exemption loophole, and the study data. - [Do Ultrasonic Mosquito Repellers Work?](https://longsleeve.com/blog/ultrasonic-repellers) The other gadget category, and the FTC cases behind it. - [Standing Water and Mosquito Control](https://longsleeve.com/blog/standing-water-mosquito-control). The one backyard measure the CDC asks for weekly. - [Mosquito Repellent for Kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). What the label age limits actually say. - [West Nile Virus in the United States](https://longsleeve.com/blog/west-nile-virus). What a bad local *Culex* season looks like. - [The species almanac](https://longsleeve.com/facts). Species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. Frick TB, Tallamy DW. Density and diversity of nontarget insects killed by suburban electric insect traps. Entomological News, 1996;107:77-82. Record: [https://www.biodiversitylibrary.org/part/31146](https://www.biodiversitylibrary.org/part/31146). Full text: [https://archive.org/details/biostor-76681](https://archive.org/details/biostor-76681) 1. Nasci RS, Harris CW, Porter CK. Failure of an insect electrocuting device to reduce mosquito biting. Mosquito News, 1983;43(2):180-184. [https://www.biodiversitylibrary.org/part/131757](https://www.biodiversitylibrary.org/part/131757) 1. Heinen JT et al. Factors affecting capture rates of insect taxa by retail electrocutors and eliminators in northern lower Michigan. The Great Lakes Entomologist, 2003;36(1-2). [https://scholar.valpo.edu/tgle/vol36/iss1/10/](https://scholar.valpo.edu/tgle/vol36/iss1/10/) 1. Jensen T et al. Field efficacy of commercial antimosquito products in Illinois. Journal of the American Mosquito Control Association, 2000;16(2):148-152. [https://pubmed.ncbi.nlm.nih.gov/10901639/](https://pubmed.ncbi.nlm.nih.gov/10901639/) 1. McMeniman CJ, Corfas RA, Matthews BJ, Ritchie SA, Vosshall LB. Multimodal integration of carbon dioxide and other sensory cues drives mosquito attraction to humans. Cell, 2014;156(5):1060-1071. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4007582/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4007582/) 1. Urban JE, Broce A. Killing of flies in electrocuting insect traps releases bacteria and viruses. Current Microbiology, 2000;41(4):267-270. [https://pubmed.ncbi.nlm.nih.gov/10977894/](https://pubmed.ncbi.nlm.nih.gov/10977894/) 1. Iowa State University Extension and Outreach, Yard and Garden. Bug Zappers are Harmful, Not Helpful (June 14, 1996). [https://yardandgarden.extension.iastate.edu/article/1996/6-14-1996/bugzapper.html](https://yardandgarden.extension.iastate.edu/article/1996/6-14-1996/bugzapper.html) 1. Penn State Extension. Got Mosquitoes? Eliminate Mosquitoes with IPM. [https://extension.psu.edu/got-mosquitoes-eliminate-mosquitoes-with-ipm](https://extension.psu.edu/got-mosquitoes-eliminate-mosquitoes-with-ipm) 1. University of Maryland Extension. Controlling Mosquitoes. [https://extension.umd.edu/resource/controlling-mosquitoes](https://extension.umd.edu/resource/controlling-mosquitoes) 1. Colorado State University Extension. Flies in the Home. [https://extension.colostate.edu/resource/flies-in-the-home/](https://extension.colostate.edu/resource/flies-in-the-home/) 1. Rutgers Center for Vector Biology. Products and Promotions That Have Limited Value for Mosquito Control. [https://vectorbio.rutgers.edu/outreach/proprom.php](https://vectorbio.rutgers.edu/outreach/proprom.php) 1. University of Florida IFAS. Electric Bug Zappers Useless For Controlling Mosquitoes (July 23, 1997). [https://blogs.ifas.ufl.edu/news/1997/07/23/electric-bug-zappers-useless-for-controlling-mosquitoes/](https://blogs.ifas.ufl.edu/news/1997/07/23/electric-bug-zappers-useless-for-controlling-mosquitoes/) 1. American Mosquito Control Association. FAQs. [https://www.mosquito.org/faqs/](https://www.mosquito.org/faqs/) 1. EPA. Pesticide Devices: A Guide for Consumers. [https://www.epa.gov/pesticides/pesticide-devices-guide-consumers](https://www.epa.gov/pesticides/pesticide-devices-guide-consumers) 1. CDC. Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC. Mosquito Control at Home. [https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-at-home.html](https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-at-home.html) 1. CDC Yellow Book. Mosquitoes, Ticks, and Other Arthropods. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. CDC. About Ticks and Tickborne Disease. [https://www.cdc.gov/ticks/about/index.html](https://www.cdc.gov/ticks/about/index.html) 1. Federal Trade Commission. FTC Warns Manufacturers, Retailers of Ultrasonic Pest-Control Devices (May 2001). [https://www.ftc.gov/news-events/news/press-releases/2001/05/ftc-warns-manufacturers-retailers-ultrasonic-pest-control-devices](https://www.ftc.gov/news-events/news/press-releases/2001/05/ftc-warns-manufacturers-retailers-ultrasonic-pest-control-devices) Last reviewed 2026-08-16 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. ## Can I Put Mosquito Repellent on My Dog? URL: https://longsleeve.com/blog/can-i-put-mosquito-repellent-on-my-dog > Only if the label says it is for animals, the EPA says. Heartworm, what NPIC says about DEET and pets, picaridin, and which products are labeled for dogs. Source: https://longsleeve.com/blog/can-i-put-mosquito-repellent-on-my-dog By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 31, 2026 · Updated September 13, 2026 **Short answer:** Do not put human mosquito repellent on your dog unless the product label specifically says it is for dogs. Human skin repellents are labeled for people, pets can lick treated skin, and pet parasite products have their own directions and risks. Use a veterinarian-recommended product labeled for your animal. ### Do dogs actually need mosquito protection? The mosquito risk that matters for a dog is heartworm, and the [FDA](https://www.fda.gov/animal-veterinary/animal-health-literacy/keep-worms-out-your-pets-heart-facts-about-heartworm-disease) says the products approved to prevent it all require a veterinarian's prescription, most of them given monthly as a topical liquid on the skin or an oral tablet. The FDA says heartworm disease results in severe lung disease, heart failure, other organ damage and death in pets, mainly dogs, cats and ferrets, and that the worms are spread through the bite of a mosquito. The CDC's parasite reference, DPDx, lists domestic dogs, coyotes, jackals and wolves as the most typical hosts and mosquitoes from several genera as the vectors. The FDA says it has been reported in dogs in all 50 states. The FDA's case for prevention is what treatment costs: it says treatment can be potentially toxic to the dog's body and can cause serious complications, such as life-threatening blood clots to the dog's lungs. The mosquitoes themselves are a yard problem, covered in [standing water and mosquito control](https://longsleeve.com/blog/standing-water-mosquito-control). The FDA says year-round prevention is best, and that which preventive is best for your dog is a conversation with your dog's veterinarian. ### The label is the boundary A repellent label is the use direction, and it is specific about who the product is for. The EPA tells people looking for a repellent to use the label to choose the right product and to follow label directions. NPIC says common repellents such as DEET, picaridin, IR3535, and oil of lemon eucalyptus can be applied to human skin, and some can be used on clothing. That sentence does not turn a human product into a dog product. ### Why dogs are a different surface A dog is not just a smaller person with fur. The coat changes coverage. The animal can lick the product. A family member may pet the dog and get residue on their own hands. NPIC describes exposure routes as skin, eyes, breathing, or eating, and notes that residues can be eaten if hands are not washed after repellent use. With pets, grooming makes that oral route harder to ignore. ### What happens if you put DEET on a dog? The [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively)'s rule is not to find out: its repellent guidance says do not use any product on pets or other animals unless the label clearly states it is for animals. NPIC's DEET fact sheet says reports of pets being exposed to DEET in amounts that would make them sick are rare, and that pets that have been overexposed have shown vomiting, shaking, excitement, lack of coordination and seizures. ASPCApro says DEET can cause significant clinical signs in companion animals, and that the higher the concentration, the more risk to the pet. [NPIC](https://npic.orst.edu/health/animhealth.html) says all pesticides have some level of toxicity, and that even the least toxic products can cause health problems if an animal is exposed to enough of it. The longer version is in [can I use DEET on my dog](https://longsleeve.com/blog/can-i-use-deet-on-my-dog). If it has already happened, NPIC says to call NPIC if you are concerned a pesticide made your pet sick, and for emergencies to contact your veterinarian or the ASPCA Animal Poison Control Center. ### Is picaridin any different for dogs? Not on the record, because the record does not mention dogs. [NPIC](http://npic.orst.edu/factsheets/PicaridinGen.html)'s picaridin fact sheet says picaridin can be used on human skin or clothing to repel mosquitoes, biting flies, ticks, fleas and chiggers, and that the products are pump sprays, liquids, aerosols or wipes. The fact sheet has no pets or animals paragraph, and no agency guidance cited on this page addresses picaridin on dogs. The species comparison NPIC does give is about absorption, and it is rats, not dogs: when researchers applied picaridin to the skin of rats, 60 percent of it went through the skin, while in humans less than 6 percent of the picaridin applied to skin was absorbed. NPIC's general note is that some animals may be more sensitive than others to the effects of certain pesticides. The agencies are silent on picaridin and dogs; we walk through that silence in [picaridin and dogs](https://longsleeve.com/blog/is-picaridin-safe-for-dogs). The label rule above governs, and [NPIC](https://npic.orst.edu/health/pets2.html) says your veterinarian can help you compare and select the most appropriate products to control insects and ticks on your pets. ### What to do instead Use products labeled for that animal, and ask your veterinarian if you are unsure. The American Veterinary Medical Association says external parasites can irritate, injure, and transmit disease to pets, and that pet owners should work with a veterinarian on prevention and treatment. That is especially important if the pet is old, very young, pregnant, sick, medicated, or lives with cats. ### Which products are actually labeled for dogs? Two kinds, under two agencies: topical pesticides such as spot-on treatments, which the EPA registers, and heartworm preventives, which are prescription drugs under the FDA. The EPA says that since the mid-1970s it and the FDA have split oversight of products applied topically to animals to treat fleas and ticks by whether the chemical is absorbed into the bloodstream (FDA) or remains on the skin (EPA). One dog label that lists mosquitoes: the EPA stamped label for K9 Advantix II Medium Dog, EPA Reg. No. 11556-142, describes the product as "Topical Prevention and Treatment of Fleas, Ticks, Mosquitoes, Biting Flies, and Lice" for use only on dogs and puppies 7 weeks and older weighing 11 to 20 pounds. The EPA's rules apply to all of them: use flea and tick control products only on the animal species and size or weight the label specifies, and remember that pesticides on your pets can be transferred to your children. Which one, and whether one is needed at all, is a veterinary call: the [EPA](https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet) says to consult your veterinarian about the best way to protect your pets from fleas and ticks and whether and when certain types of pet product applications are needed. ### The cat warning A dog product can hurt a cat, and the EPA, NPIC and the label itself all say so. [NPIC](http://npic.orst.edu/factsheets/PermGen.html) says cats are more sensitive to permethrin than dogs or people because it takes their bodies a long time to break it down. NPIC says cats accidentally exposed to products with high levels of permethrin may seem anxious, be unable to walk normally, have muscle tremors and seizures, and may die from the exposure. The EPA says never apply dog products to cats, or cat products to dogs, because some pesticides are more toxic to one species than another; NPIC says dog products should never be used on cats. Cats are in the same mosquito story: the FDA says cats can also get heartworms after being bitten by an infected mosquito, and that both indoor and outdoor cats are at risk. More on permethrin in a mixed household is in [permethrin around pets](https://longsleeve.com/blog/is-permethrin-safe-around-pets). The K9 Advantix II label's active ingredients panel lists permethrin at 44 percent. The label prints a fatality box on the back panel: DO NOT USE ON CATS, MAY BE FATAL. Keep cats away from treated dogs for 24 hours. If applied to a cat or ingested by a cat, contact your veterinarian immediately. ### Where Longsleeve fits Longsleeve is for people. It is an EPA-registered 20% picaridin insect repellent lotion, EPA Reg. No. 101457-1. Use it on human skin as directed by the label. For your dog, use a dog-labeled product. ### Common questions **Can I use Longsleeve on my dog?** No. Longsleeve is an EPA-registered insect repellent lotion for people. Do not use it on pets. **What should I use for a dog instead?** Use products labeled for dogs and follow the directions. Your veterinarian can help choose flea, tick, and mosquito protection for your dog. **Why is licking a problem?** If a pet licks treated skin, a product meant for skin contact can become an oral exposure. Labels are written around the intended route and species. **Can you spray a human bug spray on a dog?** No, unless that label says it is for animals. The EPA's repellent guidance is one sentence: "Do not use any product on pets or other animals unless the label clearly states it is for animals." The same guidance says to read and follow the label directions and to apply repellents only to exposed skin and clothing, and the EPA's pet guidance says to use flea and tick control products only on the animal species and size or weight specified by the label. **Do mosquito repellents labeled for dogs exist?** Products labeled for dogs exist: the EPA stamped label for K9 Advantix II Medium Dog, EPA Reg. No. 11556-142, lists mosquitoes among the pests it is for on dogs 7 weeks of age and older. NPIC says pesticides are used on pets to get rid of fleas, ticks and mosquitoes, and the EPA says to use flea and tick control products only on the animal species and size or weight specified by the product label. **Do mosquitoes bite dogs?** Yes. The FDA says heartworm is spread through the bite of a mosquito, and that when an infected mosquito bites a dog it spreads the infective larvae to the dog through the bite wound. The FDA also says people cannot get heartworms from their pets, because heartworms are only transmitted by the bite of an infected mosquito. ### Related reading - [Picaridin and Dogs: What the Label Decides](https://longsleeve.com/blog/is-picaridin-safe-for-dogs) - [Can I Use DEET on My Dog?](https://longsleeve.com/blog/can-i-use-deet-on-my-dog) - [Permethrin Around Dogs and Cats: What the Labels Say](https://longsleeve.com/blog/is-permethrin-safe-around-pets) - [Standing Water and Mosquitoes: Weekly Yard Checklist](https://longsleeve.com/blog/standing-water-mosquito-control) ### Sources 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. NPIC, Insect Repellents Fact Sheet. [https://npic.orst.edu/factsheets/repellents.html](https://npic.orst.edu/factsheets/repellents.html) 1. AVMA, External Parasites. [https://www.avma.org/resources-tools/pet-owners/petcare/external-parasites](https://www.avma.org/resources-tools/pet-owners/petcare/external-parasites) 1. CDC, Preventing Tick Bites. [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. FDA, Keep the Worms Out of Your Pet's Heart! The Facts about Heartworm Disease, content current as of December 22, 2022. [https://www.fda.gov/animal-veterinary/animal-health-literacy/keep-worms-out-your-pets-heart-facts-about-heartworm-disease](https://www.fda.gov/animal-veterinary/animal-health-literacy/keep-worms-out-your-pets-heart-facts-about-heartworm-disease) 1. CDC DPDx, Dirofilariasis, last reviewed June 27, 2019. [https://www.cdc.gov/dpdx/dirofilariasis/index.html](https://www.cdc.gov/dpdx/dirofilariasis/index.html) 1. EPA, Using Insect Repellents Safely and Effectively, last updated September 8, 2026. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. NPIC, DEET General Fact Sheet. [http://npic.orst.edu/factsheets/DEETgen.html](http://npic.orst.edu/factsheets/DEETgen.html) 1. ASPCApro, Don't DEET That Dog!. [https://www.aspcapro.org/resource/dont-deet-dog](https://www.aspcapro.org/resource/dont-deet-dog) 1. NPIC, Using Pesticides on Pets, last updated September 13, 2024. [https://npic.orst.edu/health/pets2.html](https://npic.orst.edu/health/pets2.html) 1. NPIC, Pesticides and Animal Health, last updated August 6, 2025. [https://npic.orst.edu/health/animhealth.html](https://npic.orst.edu/health/animhealth.html) 1. NPIC, Picaridin General Fact Sheet. [http://npic.orst.edu/factsheets/PicaridinGen.html](http://npic.orst.edu/factsheets/PicaridinGen.html) 1. EPA, EPA's Regulation of Flea and Tick Products, last updated July 6, 2026. [https://www.epa.gov/pets/epas-regulation-flea-and-tick-products](https://www.epa.gov/pets/epas-regulation-flea-and-tick-products) 1. EPA, Controlling Fleas and Ticks on Your Pet, last updated June 10, 2026. [https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet](https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet) 1. EPA Pesticide Product Label, K9 Advantix II Medium Dog, EPA Reg. No. 11556-142, notification dated February 14, 2022 (PDF). [https://www3.epa.gov/pesticides/chem_search/ppls/011556-00142-20220214.pdf](https://www3.epa.gov/pesticides/chem_search/ppls/011556-00142-20220214.pdf) 1. EPA, Protecting Pets from Fleas and Ticks, last updated September 8, 2026. [https://www.epa.gov/pets](https://www.epa.gov/pets) 1. NPIC, Permethrin General Fact Sheet. [http://npic.orst.edu/factsheets/PermGen.html](http://npic.orst.edu/factsheets/PermGen.html) Last reviewed 2026-09-21 · every claim on this page is sourced above ## Can I Use DEET on My Dog? What EPA and NPIC Say URL: https://longsleeve.com/blog/can-i-use-deet-on-my-dog > EPA says not to use any product on pets unless the label clearly states it is for animals. Its 1998 DEET review listed cats and dogs; 2014 lists horses. Source: https://longsleeve.com/blog/can-i-use-deet-on-my-dog By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 31, 2026 · Updated September 21, 2026 **Short answer:** EPA says not to use any product on pets or other animals unless the label clearly states it is for animals. NPIC says reports of pets exposed to DEET in amounts that would make them sick are rare, and lists vomiting, shaking, excitement, lack of coordination and seizures in overexposed pets. EPA's advice on fleas and ticks: consult your veterinarian. ### What does EPA say about using a human DEET repellent on a dog? [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively)'s answer is one sentence in its guidance on using insect repellents: "Do not use any product on pets or other animals unless the label clearly states it is for animals." [NPIC](http://npic.orst.edu/factsheets/DEETgen.html) describes DEET as an insect repellent used in products to prevent bites from insects such as fleas, mosquitoes and biting flies. EPA lists DEET among the active ingredients in EPA-registered skin-applied insect repellents, with more than 500 products. The label is where the permission lives. [EPA](https://www.epa.gov/insect-repellents/deet)'s DEET page says FIFRA requires that pesticides be used according to the approved label. EPA says an accepted pesticide product label represents the full content of its registration decision regarding that product, and EPA says the stamped-accepted label describes the legal requirements for sale and use of that pesticide in the United States. For skin-applied repellents, EPA says registration "indicates that they have been evaluated and approved for human safety and effectiveness when applied according to instructions on the label." The word EPA uses there is human. Take one label. OFF! Insect Repellent Formula V, EPA Reg. No. 4822-167, lists DEET at 25 percent. Its directions say to hold the container 6 to 8 inches from skin or clothing and to "use just enough repellent to cover exposed skin and/or clothing." It states that it is a violation of federal law to use the product in a manner inconsistent with its labeling. That label spells out skin and clothing. EPA's rule asks for one that clearly states it is for animals. Hold your own bottle to that test, and see our wider look at [mosquito repellent and dogs](https://longsleeve.com/blog/can-i-put-mosquito-repellent-on-my-dog). ### Was DEET once registered for use on cats and dogs? Yes. EPA's April 1998 Reregistration Eligibility Decision for DEET lists cats and dogs among the registered use sites. EPA's September 2014 interim registration review decision lists horses, plus human skin, hair and clothing. EPA's R.E.D. FACTS sheet, dated April 1998, describes DEET as an insect repellent used in households, on the human body and clothing being worn, and "on cats, dogs, horses and pet living/sleeping quarters." The full decision's use sites include "Cats (adults/kittens)" and "Dogs/canines (adults/puppies)," and its types of treatment include animal bedding or litter treatment and animal treatment by spray. The same document estimated that about 4 percent of households that had cats or dogs used DEET on those pets. The later record reads differently. [NPIC](http://npic.orst.edu/factsheets/archive/DEETtech.html)'s DEET technical fact sheet, last reviewed in July 2008, says repellents containing DEET are used on a variety of sites, "including the human body, clothing, headgear, and horses." EPA's September 2014 interim decision describes DEET as currently registered for non-food and residential uses, with one registered product for use on horses. It lists the use sites as horses, by animal treatment, and human skin, hair, clothing, footwear, shoes and headgear. It says exposure in terrestrial habitats would be limited to human skin, clothing and shoes, plus the skin and hair of horses that received DEET applications. Cats and dogs appear in none of those lines. No document we could find says when that changed, or why. So we will not give you a year or a reason. ### What has been reported in dogs exposed to DEET? NPIC's word for the reports is rare. Its DEET technical fact sheet, last reviewed in 2008, says reports of DEET toxicosis in animals are rare, and that clinical signs in dogs and cats may include vomiting, tremors, excitation, ataxia and seizures. NPIC's general fact sheet, reviewed the same year, lists vomiting, shaking, excitement, lack of coordination and seizures in overexposed pets. NPIC also describes a one-year study, and it was oral dosing, not repellent on a coat: researchers gave dogs DEET in gel capsules at 0, 30, 100 and 400 mg/kg/day, and at the highest dose noted decreased body weight, more drooling or salivation, and decreased cholesterol. A 1999 DEET paper in Toxicological Sciences reports effects in dogs that included increased incidences of emesis and ptyalism (vomiting and drooling), transient reductions in hemoglobin and hematocrit, and decreased cholesterol. It says one male dog in the high-dose group "exhibited ataxia, tremors, abnormal head movements, and/or convulsions on several occasions during the study," and it puts the highest no-observed-effect level for dogs at 100 mg/kg/day. ASPCApro, the ASPCA's professional resource, says DEET can cause significant clinical signs in companion animals, and that the higher the concentration, the more risk to the pet. ASPCApro also says GI upset is very commonly seen with exposure to DEET, and that with a product of 80 percent DEET or more you may see ataxia, disorientation, tremors and seizures. Rare is a rate. EPA's label rule still decides what goes on the dog. For people, we cover [the human evidence on DEET](https://longsleeve.com/blog/deet-safety-evidence) separately. ### What is actually labeled for use on the dog? Products whose own labels name dogs, chosen with your veterinarian. [FDA](https://www.fda.gov/animal-veterinary/animal-health-literacy/keep-worms-out-your-pets-heart-facts-about-heartworm-disease) says the worms behind heartworm disease are spread through the bite of a mosquito, and that the disease results in severe lung disease, heart failure, other organ damage and death in pets, mainly dogs, cats and ferrets. FDA says it has been reported in dogs in all 50 states. FDA says many products are approved to prevent heartworms in dogs, and that all of them require a veterinarian's prescription. For fleas and ticks, [EPA](https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet) says products for pets are available in many forms, and that you should use them only on the animal species and size or weight specified by the product label. EPA also says most insect repellents do not work against lice or fleas. One label that names dogs: K9 Advantix II Medium Dog, EPA Reg. No. 11556-142, a topical product for monthly use only on dogs and puppies 7 weeks of age and older and weighing 11 to 20 lbs. Its label says it is for external use only, and tells you not to get it in your dog's eyes or allow your dog to ingest it. It is here only as an example of a label that names dogs. We take the same label-first look at [picaridin and dogs](https://longsleeve.com/blog/is-picaridin-safe-for-dogs) and at [permethrin around pets](https://longsleeve.com/blog/is-permethrin-safe-around-pets). [NPIC](https://npic.orst.edu/health/pets2.html) says your veterinarian can help you compare and select the most appropriate products to control insects and ticks on your pets. EPA says to consult your veterinarian about the best way to protect your pets from fleas and ticks. ### Who do you call if your dog licked DEET or got sprayed? Your veterinarian, or the ASPCA Animal Poison Control Center at 1-888-426-4435: those are the two contacts NPIC gives for emergencies. NPIC adds that if you are concerned that a pesticide made your pet sick, you can call NPIC at 800-858-7378 to discuss the incident. EPA's page on flea and tick products for pets says to contact your veterinarian and/or the National Pesticide Information Center at 1-800-858-7378 right away for information on whether additional measures are needed to help your pet recover. The ASPCA says its Poison Control service is your best resource for any animal poison-related emergency, 24 hours a day, 365 days a year. The ASPCA also says a consultation fee may apply. If you suspect that you or your child is having an adverse reaction to a DEET product, EPA says to discontinue use, wash treated skin, and call your local poison control center or physician, and to take the repellent container with you if you go to a doctor. We found no agency page with a home instruction for a dog that licked DEET or got sprayed with it, so we will not write one. Call your veterinarian, or the poison control line NPIC names, 1-888-426-4435. ### The people-and-pets split Use human repellents on humans, as directed. Use pet products on pets, as directed. If you hike with a dog, that can mean Longsleeve on your exposed skin and a veterinarian-recommended flea and tick product on the dog. Same outing, different labels. ### Common questions **Is DEET toxic to dogs?** NPIC says reports of DEET toxicosis in animals are rare, and that clinical signs in dogs and cats may include vomiting, tremors, excitation, ataxia and seizures. NPIC also says all pesticides have some level of toxicity, and that even the least-toxic products can cause health problems if an animal is exposed to enough of it. NPIC adds that some animals may be more sensitive than others. **Can I spray DEET on myself around my dog?** NPIC 's general instruction for pesticides is to remove pets from the area before you begin applying them. ASPCApro says that if a pet is sprayed in the eyes you may see conjunctivitis, lethargy, uveitis and corneal ulceration, among other signs, and that inhalation exposures can cause airway inflammation and dyspnea (difficulty breathing). EPA says to read the label first and to keep all products out of the reach of pets and children. **What if my dog licked DEET?** Call your veterinarian or the ASPCA Animal Poison Control Center at 1-888-426-4435, the two contacts NPIC gives for emergencies. The ASPCA says a consultation fee may apply. **Does the label on my bug spray say anything about dogs?** One DEET label, OFF! Insect Repellent Formula V, EPA Reg. No. 4822-167, says to hold the container 6 to 8 inches from skin or clothing. EPA's test for any bottle: do not use any product on pets or other animals unless the label clearly states it is for animals. **What can you spray on dogs to keep ticks off?** EPA says flea and tick products for pets are available in many forms, and that you should use them only on the animal species and size or weight specified by the product label. EPA also says to consult your veterinarian about the best way to protect your pets from fleas and ticks. **What about cats?** NPIC says dog products should never be used on cats, and that certain pesticides are more toxic to one species compared to the other. The EPA stamped label for K9 Advantix II Medium Dog, EPA Reg. No. 11556-142, prints it in capitals: DO NOT USE ON CATS or other animals. ### Related reading - [Can I Put Mosquito Repellent on My Dog?](https://longsleeve.com/blog/can-i-put-mosquito-repellent-on-my-dog) - [Picaridin and Dogs: What the Label Decides](https://longsleeve.com/blog/is-picaridin-safe-for-dogs) - [Permethrin Around Dogs and Cats: What the Labels Say](https://longsleeve.com/blog/is-permethrin-safe-around-pets) - [DEET Safety: EPA Reviews, CDC Guidance, Kids, and Common Questions](https://longsleeve.com/blog/deet-safety-evidence) ### Sources 1. EPA, Using Insect Repellents Safely and Effectively, last updated on November 10, 2025. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. NPIC, DEET General Fact Sheet, Date Reviewed: July 2008. [http://npic.orst.edu/factsheets/DEETgen.html](http://npic.orst.edu/factsheets/DEETgen.html) 1. EPA, Controlling Fleas and Ticks on Your Pet, last updated on June 10, 2026. [https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet](https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet) 1. EPA, Skin-Applied Repellent Ingredients, last updated on January 23, 2026. [https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients) 1. EPA, DEET, last updated on May 27, 2026. [https://www.epa.gov/insect-repellents/deet](https://www.epa.gov/insect-repellents/deet) 1. EPA, Pesticide Product and Label System (PPLS) home page, new labels added September 19, 2026. [https://ordspub.epa.gov/ords/pesticides/f?p=PPLS:1](https://ordspub.epa.gov/ords/pesticides/f?p=PPLS:1) 1. EPA, Regulation of Skin-Applied Repellents, last updated on June 25, 2026. [https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents](https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents) 1. EPA stamped label, OFF! INSECT REPELLENT FORMULA V, EPA Reg. No. 4822-167, notification accepted July 30, 2026. [https://www3.epa.gov/pesticides/chem_search/ppls/004822-00167-20260730.pdf](https://www3.epa.gov/pesticides/chem_search/ppls/004822-00167-20260730.pdf) 1. EPA, Reregistration Eligibility Decision (RED): DEET, case 0002, April 1998. [https://archive.epa.gov/pesticides/reregistration/web/pdf/0002red.pdf](https://archive.epa.gov/pesticides/reregistration/web/pdf/0002red.pdf) 1. EPA, DEET Interim Registration Review Decision, docket EPA-HQ-OPP-2012-0162, September 2014. [http://www.regulations.gov/document/EPA-HQ-OPP-2012-0162-0012](http://www.regulations.gov/document/EPA-HQ-OPP-2012-0162-0012) 1. EPA, R.E.D. FACTS: DEET, EPA-738-F-95-010, April 1998. [https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/fs_PC-080301_1-Apr-98.pdf](https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/fs_PC-080301_1-Apr-98.pdf) 1. NPIC, DEET Technical Fact Sheet, Date Reviewed: July 2008. [http://npic.orst.edu/factsheets/archive/DEETtech.html](http://npic.orst.edu/factsheets/archive/DEETtech.html) 1. Schoenig et al., Evaluation of the chronic toxicity and oncogenicity of N,N-diethyl-m-toluamide (DEET), Toxicological Sciences, January 1999. [https://pubmed.ncbi.nlm.nih.gov/10048158/](https://pubmed.ncbi.nlm.nih.gov/10048158/) 1. ASPCApro, Don't DEET That Dog! (article). [https://www.aspcapro.org/resource/dont-deet-dog](https://www.aspcapro.org/resource/dont-deet-dog) 1. FDA, Keep the Worms Out of Your Pet's Heart! The Facts about Heartworm Disease, content current as of 12/22/2022. [https://www.fda.gov/animal-veterinary/animal-health-literacy/keep-worms-out-your-pets-heart-facts-about-heartworm-disease](https://www.fda.gov/animal-veterinary/animal-health-literacy/keep-worms-out-your-pets-heart-facts-about-heartworm-disease) 1. EPA stamped label, K9 Advantix II Medium Dog, EPA Reg. No. 11556-142, notification dated February 14, 2022. [https://www3.epa.gov/pesticides/chem_search/ppls/011556-00142-20220214.pdf](https://www3.epa.gov/pesticides/chem_search/ppls/011556-00142-20220214.pdf) 1. NPIC, Using Pesticides on Pets, last updated September 13, 2024. [https://npic.orst.edu/health/pets2.html](https://npic.orst.edu/health/pets2.html) 1. ASPCA, Animal Poison Control. [https://www.aspca.org/pet-care/animal-poison-control](https://www.aspca.org/pet-care/animal-poison-control) 1. NPIC, Pesticides and Animal Health, last updated August 06, 2025. [https://npic.orst.edu/health/animhealth.html](https://npic.orst.edu/health/animhealth.html) 1. NPIC, Pesticide Use Around Pets, last updated April 14, 2026. [https://npic.orst.edu/health/pets.html](https://npic.orst.edu/health/pets.html) 1. EPA, Read the Label First: Protect Your Pets, last updated on March 23, 2026. [https://www.epa.gov/pets/read-label-first-protect-your-pets](https://www.epa.gov/pets/read-label-first-protect-your-pets) Last reviewed 2026-09-21 · every claim on this page is sourced above ## How Long Chigger Bites Itch, and Why They Look Like They Spread URL: https://longsleeve.com/blog/chigger-bites > Chigger bites itch for up to a week and heal in up to two. Why they seem to spread, why they cluster at the waistband, and when a month of itch needs a doctor. Source: https://longsleeve.com/blog/chigger-bites By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 26, 2026 · Updated September 3, 2026 **Short answer:** Chigger bites itch for up to a week and can take up to two weeks to heal, per the Army Public Health Center's chigger factsheet. They seem to spread because, the same Army Public Health Center factsheet says, digestive enzymes keep irritating skin long after the mite drops off. Chiggers are the larval stage of a mite, a relative of ticks. ### How long do chigger bites itch? Up to a week, with complete healing taking up to two weeks, per the Army Public Health Center's chigger factsheet, which also puts the start of itching at roughly one to three hours after the bite. University of Maryland Extension gives a later onset, three to six hours after attachment, and agrees the itch may persist for up to two weeks. StatPearls, a peer-reviewed clinical reference on the NCBI Bookshelf, says it usually resolves within a few days but may last as long as two weeks. That is the baseline. If yours are well outside it, keep reading. ### Why are my chigger bites still itching after a month? A month is longer than any documented chigger itch we could find. The Army Public Health Center's factsheet says itching persists up to a week and healing takes up to two. StatPearls says a few days, up to two weeks, and sets the outer bound: the larva rarely stays attached beyond 48 hours, but the intense itching, inflammation and localized allergic response may last for weeks. Weeks, in every source. So at a month, something else may be going on. StatPearls lists what clinicians consider when a rash looks like chigger bites: scabies, bed bug bites, exposure to mosquitoes or ants, and flea bites, which can also line up along tight clothing, especially with indoor animals. On scabies, the [CDC](https://www.cdc.gov/scabies/about/index.html) explains that the itch is a hypersensitivity reaction to the mites and their feces, and may continue for several weeks after treatment, even when every mite and egg is killed. StatPearls also says chigger bites should not be the presumed diagnosis in anyone who appears ill, has abnormal vital signs, has extensive blisters, or whose lesions hurt rather than itch. University of Maryland Extension adds that scratching can result in a secondary infection. The [CDC](https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html) says see a healthcare provider if symptoms worsen. A month of itching is that moment. ### Do chigger bites spread when you scratch them? No. There is usually nothing left to spread. StatPearls notes the mite has usually dislodged before the irritation even begins, and that larvae dislodge easily when scratched and rarely remain attached beyond 48 hours. University of Maryland Extension puts it plainly: scratching often removes the mite. The Army Public Health Center's factsheet explains that the bite site stays irritated by the digestive enzymes long after the chigger detaches. Bumps that turn up later are not one bite moving. They line up because, as StatPearls describes, the mites migrate to thin protected skin along the borders of tight clothing, and the Army Public Health Center factsheet and University of Maryland Extension put the start of itching anywhere from one to six hours after a bite. The real risk is infection. University of Maryland Extension says scratching can result in a secondary infection, and the Army factsheet agrees: once a bump has formed, do not scratch it. ### Are chigger bites contagious? You pick chiggers up from vegetation. University of Maryland Extension describes the larvae crawling on the soil or up grass blades in search of a host. StatPearls notes the larva rarely remains attached to a human beyond 48 hours. What remains after that is an irritated bite, not a living mite. The Army Public Health Center's factsheet explains that the site stays irritated by the digestive enzymes long after the chigger detaches. Chigger bites start where the larvae wait, on soil and grass blades. ### Do chiggers burrow into your skin? No. The Army Public Health Center's chigger factsheet is blunt: contrary to popular belief, chiggers do not burrow into the skin or suck blood. The Army Public Health Center factsheet describes the larva cutting the skin with blade-like mouthparts called chelicerae and injecting an enzyme that digests skin at the bite site; the cells around the wound harden into what the factsheet calls a drinking straw. The Illinois Department of Public Health says the same thing about the cut and the saliva: chiggers do not suck blood, they cut into the skin, inject skin-digesting saliva and suck up the liquefied skin. StatPearls explains where the myth comes from: as the larva liquefies skin cells, the skin swells into a papule around the mite, giving the impression it has burrowed in. And since, per StatPearls, the mite has usually dislodged before the irritation begins, it can sometimes be seen in the papule but usually is not. ### Do chigger bites blister? Sometimes, and usually small ones. StatPearls describes red papules that may appear in clusters, with surrounding flat marks, small blisters and, rarely, large blisters. A few small blisters in a cluster of red bumps fits. Extensive blistering does not: StatPearls says chigger bites should not be the presumed diagnosis in anyone with extensive blisters or whose lesions hurt rather than itch. University of Maryland Extension notes scratching can result in a secondary infection, and the CDC's signs of an infected bite apply: red, warm, or a red streak spreading outward. Leave the blisters alone and watch for those. The CDC says see a healthcare provider if symptoms worsen. ### Do adult chiggers bite? No. Only the larva bites people. The Army Public Health Center's factsheet states that chigger nymphs and adults do not bite humans; they feed on small, soil-dwelling insects and insect eggs. The Illinois Department of Public Health says the nymph and adult stages prey on insects; only the six-legged larva bites people. The leg count is the tell. Illinois DPH explains that mites, like their relatives the ticks, pass through egg, larva, nymph and adult, and every stage has eight legs except the six-legged larva. The thing that bit you had six; everything it grows into has eight. As for whether chiggers die after biting: nothing in the sources says so. ### Why do chigger bites show up at the waistband and sock line? Because chiggers go looking for thin skin under tight clothing. The Army Public Health Center's factsheet says they prefer to bite where clothing fits tightly, such as around waistlines, sock lines and behind the knees. StatPearls explains why: the mites migrate on the body to a protected area with thin skin and accumulate along the borders of tightly fitting clothing, so several bites in a linear pattern may occur along the waistband, the in-seam of underwear, or above socks or shoes. The Army factsheet's fix follows directly: loose-fitting, tightly woven fabrics, to prevent chiggers from moving through clothing. ### Chigger bites vs bed bug bites vs mosquito bites StatPearls lists bed bug bites and mosquito exposure among what clinicians consider when a rash looks like chigger bites. Other small clustered bites, such as [no-see-um bites](https://longsleeve.com/blog/no-see-um-bites) and [sand flea bites](https://longsleeve.com/blog/sand-flea-bites), have their own tells. Attribute Chigger bites Bed bug bites Mosquito bites What bit you Six-legged larval mite, a relative of ticks (Illinois DPH) Bed bug: reddish-brown, wingless, 1 mm to 7 mm (CDC) A mosquito How you get bitten Outdoors, from larvae on soil or grass blades (University of Maryland Extension) At night, while you sleep (CDC) Day and night (CDC) When the itch starts One to three hours (Army Public Health Center); three to six (University of Maryland Extension) Marks noticed one to several days later (CDC) No source Where on the body Waistlines, sock lines, behind the knees, tight-clothing borders (Army Public Health Center, StatPearls) No source No source What it looks like Red papules in clusters, sometimes in a line along a waistband or sock, sometimes small blisters (StatPearls) No source No source How long it lasts Itch up to a week, healing up to two weeks (Army Public Health Center) No source No source How do you treat chigger bites? Shower first, then treat the itch. The Illinois Department of Public Health advises a hot, soapy bath or shower immediately after visiting natural areas where chiggers are present, to dislodge any that have attached. Next, the CDC's first bite-care step: wash the bite and surrounding area with soap and water. Then symptom control. StatPearls calls management supportive: oral antihistamines or topical corticosteroid creams, with cold compresses for discomfort and swelling. The CDC's version is an over-the-counter anti-itch or antihistamine cream, used per the label. More in our guide to [mosquito bite treatment](https://longsleeve.com/blog/mosquito-bite-treatment). StatPearls says suffocating the parasite with nail polish, vaseline or cream is not recommended; usually there is no parasite left to suffocate. The Army Public Health Center's factsheet goes further: never apply household products such as kerosene, turpentine, ammonia, alcohol, gasoline, salt or dry cleaning fluid to the affected area. And do not scratch: the Army factsheet warns that scratching a formed bump risks infection, and the CDC says to see a healthcare provider if symptoms worsen. ### Can chigger bites make you sick? In the United States, no. University of Maryland Extension states that chiggers are not known to transmit any infectious diseases in the United States. The Army Public Health Center's factsheet agrees, adding that feeding larvae can cause extreme skin irritation. The exception is geographic. The CDC describes scrub typhus as a disease caused by the bacterium Orientia tsutsugamushi and spread through bites of infected chiggers. Most cases, per the [CDC](https://www.cdc.gov/typhus/about/scrub.html), occur in rural Southeast Asia, Indonesia, China, Japan, the Indian subcontinent and northern Australia; the Army factsheet adds the islands of the southwest Pacific. If you were bitten there and feel unwell afterward, tell your doctor where you were. In the United States, the realistic risk is secondary infection from scratching. The CDC's signs are a bite that appears red, feels warm, or grows a red streak spreading outward; if that happens, or symptoms worsen, the CDC says see a healthcare provider. ### How do you keep chiggers from biting you? Stay out of the grass they wait in, cover up, and use a repellent whose label names them. University of Maryland Extension describes the larvae crawling on the soil or up grass blades in search of a host. Ticks are their relatives, per Illinois DPH; our [tick season guide](https://longsleeve.com/blog/tick-season-when) covers that side of the family. The Army Public Health Center's factsheet recommends loose-fitting, tightly woven fabrics to prevent chiggers from moving through clothing. On treated clothing, Illinois DPH is emphatic: permethrin repellents should never be applied to skin, they are for clothing only, always according to the label. Our [permethrin-treated clothing](https://longsleeve.com/blog/permethrin-clothing) guide covers how that works. On skin, the National Pesticide Information Center states that picaridin repels insects, ticks and chiggers. And per the [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively), always read the product label before using it. Our [chigger repellent guide](https://longsleeve.com/blog/chigger-repellent) covers what to look for on a label, and our [facts page](https://longsleeve.com/facts) sets four repellent options side by side. Back inside, the Illinois DPH step: a hot, soapy shower right away to dislodge anything attached. ### Common questions **Can chigger bites itch for months?** Not according to any source we could find. The Army Public Health Center puts itching at up to a week; StatPearls says up to two weeks, with inflammation that may last for weeks. A month or more points toward something else on the clinical differential, such as scabies or bed bugs, or toward a secondary infection. See a clinician. **Can you spread chiggers by scratching?** No. StatPearls notes the mite has usually dislodged before the irritation begins, and that larvae dislodge easily when scratched and rarely stay attached for more than 48 hours. University of Maryland Extension says scratching often removes the mite. What scratching does risk is a secondary infection, so leave the bumps alone. **Can chiggers be passed from one person to another?** Chiggers come from the ground. University of Maryland Extension says the larvae crawl on soil or up grass blades to find a host, and StatPearls says a larva rarely stays attached for more than 48 hours. After that, per the Army Public Health Center, what remains is a bite site irritated by digestive enzymes, with no mite in it. **Does nail polish on a chigger bite help?** No. StatPearls says covering the bite in nail polish, vaseline or cream to suffocate the mite is not recommended. The idea rests on the myth that the chigger is inside the skin; the Army Public Health Center's factsheet says chiggers do not burrow. The Army Public Health Center factsheet warns never to put kerosene, alcohol, ammonia or similar household products on a bite. **Do chiggers die after biting you?** The sources do not say they die. StatPearls says the larva dislodges, usually within 48 hours. The Illinois Department of Public Health describes the life cycle continuing from larva to nymph to adult, and the Army Public Health Center says nymphs and adults do not bite humans; they feed on small soil-dwelling insects and insect eggs. ### About Longsleeve Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours, and its accepted federal label carries the claim "Repels biting flies, stable flies, black flies, gnats, chiggers, sand flies and Scottish biting midges (no see-ums) for up to 8 hours." It is fragrance-free, with nine disclosed ingredients. Of the 631 EPA-registered skin repellents in [our Repellent Index](https://longsleeve.com/repellent-index), 77 carry a stated chigger protection time you can read off their federal label. None of this is medical advice. If you develop a rash or a fever after a bite, call your doctor and tell them what bit you. ### Related reading - [Permethrin-treated clothing](https://longsleeve.com/blog/permethrin-clothing). The clothing-only rule, and how treated fabric works. - [Chigger repellent guide](https://longsleeve.com/blog/chigger-repellent). How to read a label for a stated chigger protection time. - [No-see-um bites](https://longsleeve.com/blog/no-see-um-bites). Another small, clustered, itchy bite that gets mistaken for chiggers. - [Sand flea bites](https://longsleeve.com/blog/sand-flea-bites). The other misidentified outdoor bite. - [Mosquito bite treatment](https://longsleeve.com/blog/mosquito-bite-treatment). The CDC bite-care protocol in full. More Longsleeve in your Google feed: ### Sources 1. US Army Public Health Center, Entomological Sciences Division, Chiggers Fact Sheet 18-025-1018. [https://ph.health.mil/resources/Chiggers_FS_18-025-1018.pdf](https://ph.health.mil/resources/Chiggers_FS_18-025-1018.pdf) 1. Illinois Department of Public Health, Mites Affecting Humans. [https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/mites-affecting-humans.html](https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/mites-affecting-humans.html) 1. University of Maryland Extension, Chiggers. [https://extension.umd.edu/resource/chiggers/](https://extension.umd.edu/resource/chiggers/) 1. StatPearls (NCBI Bookshelf), Chigger Bites and Trombiculiasis, last updated February 25, 2024. [https://www.ncbi.nlm.nih.gov/books/NBK538528/](https://www.ncbi.nlm.nih.gov/books/NBK538528/) 1. CDC, About Scabies. [https://www.cdc.gov/scabies/about/index.html](https://www.cdc.gov/scabies/about/index.html) 1. CDC, About Mosquito Bites. [https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html](https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html) 1. CDC, About Bed Bugs. [https://www.cdc.gov/bed-bugs/about/index.html](https://www.cdc.gov/bed-bugs/about/index.html) 1. CDC, About Mosquitoes. [https://www.cdc.gov/mosquitoes/about/index.html](https://www.cdc.gov/mosquitoes/about/index.html) 1. CDC, About Typhus Fevers. [https://www.cdc.gov/typhus/about/index.html](https://www.cdc.gov/typhus/about/index.html) 1. CDC, About Scrub Typhus. [https://www.cdc.gov/typhus/about/scrub.html](https://www.cdc.gov/typhus/about/scrub.html) 1. Illinois Department of Public Health, DEET and Insect Repellents. [https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/deet-insect-repellents.html](https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/deet-insect-repellents.html) 1. National Pesticide Information Center, Picaridin General Fact Sheet. [https://npic.orst.edu/factsheets/PicaridinGen.html](https://npic.orst.edu/factsheets/PicaridinGen.html) 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) Last reviewed 2026-09-03 · every claim on this page is sourced above ## Chigger Repellent: DEET, Picaridin, Labels, and Showering URL: https://longsleeve.com/blog/chigger-repellent > How to choose chigger repellent using Illinois DPH, NPIC, and EPA guidance: DEET, picaridin, label claims, exposed skin, clothing, and the post-grass shower. Source: https://longsleeve.com/blog/chigger-repellent By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 26, 2026 Illinois DPH calls repellent the first line of defense against chiggers, naming 7 to 30 percent DEET; [NPIC](https://npic.orst.edu/factsheets/PicaridinGen.html) states picaridin repels insects, ticks and chiggers. Check the product's own federal label for a chigger claim: of 631 EPA-registered skin repellents, 77 state a chigger protection time. Chiggers are the reason a July walk through tall grass can cost you a week of ankle-scratching. The good news is that this is a solved problem: public health guidance on chigger repellent is unusually specific, and the label on the bottle will tell you whether a product has registered a claim against them. Here is the whole picture. ### What do the public health agencies actually recommend? The Illinois Department of Public Health is as direct as guidance gets: for chiggers, "insect repellents containing 7 percent to 30 percent 'DEET' should be used as the first line of defense." That is the state-health-department baseline. **Short answer:** Illinois DPH names insect repellent containing 7 to 30 percent DEET as the first line of defense against chiggers, and NPIC states that picaridin repels insects, ticks, and chiggers. For any product, check the federal label for a chigger claim and follow EPA application directions. After exposure, Illinois DPH advises a hot, soapy shower to dislodge attached chiggers. Either way, [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively)'s standing rule is the one to remember at the shelf: "always read the product label before using the product." A chigger claim is a registered, pest-specific statement, and the label is where it lives. ### Why does the label matter so much for chiggers? Because chiggers are mites, not insects. The CDC describes them as "larval mites," and a repellent label's claims are written pest by pest: a product that says "repels mosquitoes" has told you nothing about mites. Even EPA's consumer search tool only filters by mosquitoes, ticks or both, plus protection time and active ingredient, so chiggers never appear as a checkbox. The only place a chigger answer exists is the label itself. That is a tedious thing to check across a store shelf, so we did it across the whole registry. [The Repellent Index](https://longsleeve.com/repellent-index) holds all 631 EPA-registered skin-applied repellents with the pest claims we could read off each product's federal label. Of those 631, 77 carry a stated chigger protection time. The [full statistics](https://longsleeve.com/repellent-index/statistics) and the dataset are free. ### What does a chigger actually do, and why does repellent placement matter? Illinois DPH's description of the attack is useful for aiming your repellent. Chiggers wait in soil and low vegetation, detect the carbon dioxide you exhale, climb up and grab on. They do not suck blood; they cut into skin, inject skin-digesting saliva, and if not dislodged will feed for several days, leaving a bite that becomes inflamed, hardens and itches. They start at ground level, which means ankles, socks and lower legs are the front line. Chiggers live in cracks in the soil, typically in rural and less disturbed areas, though the department notes they can persist for years on soil in new subdivisions. If your yard used to be a field, assume the field's residents stayed. EPA's application rules finish the job: read and follow the label directions, apply only to exposed skin and/or clothing, and never under clothing. For children, do not apply to their hands; apply to your own hands first, then put it on the child. When you come back in, wash treated skin and clothes with soap and water. ### What works alongside repellent? - **The hot, soapy shower.** Illinois DPH: take one "immediately after visiting natural areas where chiggers are present" to dislodge any chiggers that have attached. Because a chigger feeds for days if left alone, this one habit removes most of the damage even when the repellent missed a spot. - **Clothing as a barrier.** The general biting-pest guidance from Illinois DPH pairs repellents with protective clothing: long sleeves, long pants, hats, and avoiding the areas and hours where the pests are thickest. For chiggers specifically, pants over socks through tall grass denies them the skin they reach first. - **Know the terrain.** Grass edges, brush, unmowed field: chigger country. The middle of a mowed lawn mostly is not. One more habit that costs nothing: check yourself for where the bites would be. Chiggers work the pinch points, sock lines, waistbands, the backs of knees, and they need hours of contact to do their worst. Repellent going on before the walk, and the shower coming right after it, brackets the exposure window from both ends. That bracket, not any single product, is the actual system. ### Is there a disease risk? The chigger-borne disease the CDC tracks is scrub typhus, spread through bites of infected chiggers. Most cases occur in rural areas of Southeast Asia, Indonesia, China, Japan, the Indian subcontinent, and northern Australia. For most readers of this page, the chigger problem is the itch, not infection, and the repellent-plus-shower routine handles it. Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours, and its accepted federal label carries the claim "Repels biting flies, stable flies, black flies, gnats, chiggers, sand flies and Scottish biting midges (no see-ums) for up to 8 hours." It is fragrance-free, with nine disclosed ingredients. ### Short answers **What is the best chigger repellent?** No agency ranks products. Illinois DPH names 7 to 30 percent DEET as the first line of defense, and NPIC states that picaridin repels insects, ticks and chiggers. From there, check the individual label for a chigger claim: 77 of the 631 registered skin repellents carry one with a stated protection time. **Does picaridin work on chiggers?** NPIC's fact sheet states that picaridin repels insects, ticks and chiggers. Whether a specific product carries a chigger claim, and for how many hours, is on that product's federal label. **Where should I apply chigger repellent?** Per EPA, only to exposed skin and/or clothing, never under clothing, following the label directions. Chiggers start at ground level, so ankles and lower legs are the front line. For children, EPA says to apply to your own hands first, then to the child. **Do I still need the shower if I wore repellent?** Yes. Illinois DPH advises a hot, soapy bath or shower immediately after visiting chigger areas to dislodge any that attached anyway. A chigger left in place can feed for several days, so the shower is cheap insurance. Already bitten? [What chigger bites are and how to treat them](https://longsleeve.com/blog/chigger-bites). Same grass, different bite: [know your ticks](https://longsleeve.com/blog/tick-identification). ### Related reading - [Chigger Bites](https://longsleeve.com/blog/chigger-bites). How long they itch and why they look like they spread. - [Permethrin-Treated Clothing](https://longsleeve.com/blog/permethrin-clothing). How often to re-treat, how long it lasts, and why it never goes on skin. - [Insect Repellent for Hiking](https://longsleeve.com/blog/insect-repellent-for-hiking). Ticks, mosquitoes, permethrin, and skin repellent. - [Picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet). Duration, kids, ticks, and materials. More Longsleeve in your Google feed: ### Sources 1. Illinois Department of Public Health, Mites Affecting Humans. [https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/mites-affecting-humans.html](https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/mites-affecting-humans.html) 1. Illinois Department of Public Health, Biting Flies. [https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html](https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html) 1. NPIC, Picaridin General Fact Sheet. [https://npic.orst.edu/factsheets/PicaridinGen.html](https://npic.orst.edu/factsheets/PicaridinGen.html) 1. CDC, About Typhus Fevers. [https://www.cdc.gov/typhus/about/index.html](https://www.cdc.gov/typhus/about/index.html) 1. CDC, About Scrub Typhus. [https://www.cdc.gov/typhus/about/scrub.html](https://www.cdc.gov/typhus/about/scrub.html) 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) Last reviewed 2026-08-26 · every claim on this page is sourced above ## Do Citronella Candles Work? Evidence on Plant-Based Repellents URL: https://longsleeve.com/blog/citronella-and-plant-repellents > EPA on citronella candles, registration, and citronella plants. Candles cut bites 42 percent in one field trial and had no effect in a wind tunnel. Source: https://longsleeve.com/blog/citronella-and-plant-repellents By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 6, 2026 · Updated September 13, 2026 Citronella candles work a little, and mostly up close. One field trial found 42 percent fewer bites near citronella candles; an indoor trial put citronella candle repellency at 29 percent; a wind tunnel study found no effect. Plant oils evaporate fast. EPA registration is the dividing line: registered products were reviewed for effectiveness, exempt ones were not. People have used plants to repel insects for thousands of years, and many plant extracts and oils genuinely repel mosquitoes. The trouble is duration and delivery. Here is what the trials measured and what EPA registration does and does not mean. ### Do citronella candles actually reduce bites? Some, in some settings, and the numbers are modest. One field trial ran in a deciduous woodlot in Guelph, Ontario, in the summer of 1995. Eight identically dressed subjects took five-minute biting counts at grid positions holding 3 percent citronella candles, 5 percent citronella incense, plain candles, or none. Subjects averaged 6.2 bites per 5 minutes at the citronella candle positions and 10.8 at untreated ones. The authors called the "overall reduction in bites provided by the citronella candles and incense" for the two formats "only 42.3 and 24.2%, respectively." **Short answer:** Citronella candles can reduce mosquito bites in some studies, mostly close to the candle, but the effect is modest and inconsistent. Published trials reported reductions such as 42.3 percent in one field study and 29.0 percent repellency in one indoor study, while a wind tunnel study found no effect. EPA registration is the dividing line for product claims: registered repellents are reviewed for safety and effectiveness when used according to the label; exempt products are not reviewed by EPA for effectiveness. The lesson is in the distance data. A candle loads the air right around it, and repellency dropped significantly at 2 m and 3 m. It does not replace CDC advice to empty and scrub water-holding containers once a week, which we cover in our [standing water guide](https://longsleeve.com/blog/standing-water-mosquito-control). See also our [Asian tiger mosquito guide](https://longsleeve.com/blog/asian-tiger-mosquito). ### Why do plant oils wear off so fast? Volatility. The Malaria Journal review states it directly: plant oils repel mosquitoes "with their effect lasting from several minutes to several hours. Their active ingredients tend to be highly volatile, so although they are effective repellents for a short period after application, they rapidly evaporate leaving the user unprotected." On citronella: "Initially, citronella ... is as effective dose for dose as DEET, but the oils rapidly evaporate causing loss of efficacy." The review puts citronella-based protection from host-seeking mosquitoes at "about two hours," while stressing that formulation matters a great deal. The 2002 New England Journal of Medicine comparison tested 15 volunteers in a controlled laboratory environment with mosquito species, age, and hunger held constant. A soybean-oil-based repellent "protected against mosquito bites for an average of 94.6 minutes." Every other botanical product tested "provided protection for a mean duration of less than 20 minutes." A 2011 meta-analysis reported its finding as a gap, not an absolute: using the cage method against *Aedes*, protection time for citronella oil "was less than that in the DEET (N,N-diethyl-m-toluamide) group, with a difference in protection time of 253 min (95% confidence interval: 169-336)." Its conclusion was that citronella products "are less effective than DEET products in terms of duration of protection," and that "adding vanillin to citronella oil products could prolong the protection time." The same review found that with the room method, citronella oil, alone or with vanillin, "provided complete repellency at least 3 h." Ticks behave the same way. A CDC *Emerging Infectious Diseases* perspective describes a study running 19 exempt active ingredients as 10 percent lotion emulsions against female blacklegged ticks in the EPA-recommended human skin bioassay. Complete protection times ran from under 10 minutes for oils including castor and soybean, to more than 10 minutes but under an hour for a band that included citronella oil, up to 1 to 2 hours for cinnamon, clove, and geraniol oils. No exempt ingredient exceeded 2 hours; the DEET control held for the full 6-hour observation. The picture is not uniform. The same perspective cites a laboratory study on nymphal castor bean ticks reporting "sustained repellency ... up to 8 hours after application of 10% solutions of citronella oil (83% repellency by the eight-hour time point), clove oil (78%), and geraniol oil (67%)," with "similar or better repellency than a 10% DEET solution," which held 71 percent at 8 hours. Duration numbers do not travel between species and test methods. ### Which plant repellents carry EPA registration? Both categories exist, and the same plant can appear in both. EPA's list of active ingredients in registered skin-applied repellents includes catnip oil, oil of citronella, DEET, IR 3535, p-Menthane-3,8-diol, oil of lemon eucalyptus, picaridin, and 2-undecanone. Next to oil of citronella, [EPA](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients) notes "3 registered products; also used in unregistered products that meet the requirements for exemption from registration." What registration buys is a review. [EPA](https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents): "EPA registration of skin-applied repellent products indicates that they have been evaluated and approved for human safety and effectiveness when applied according to instructions on the label." CDC names six active ingredients found in registered products, DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, and 2-undecanone, tagging oil of lemon eucalyptus and 2-undecanone as plant-derived. The same list runs in CDC tick guidance, covered in our [Lyme guide](https://longsleeve.com/blog/lyme-disease-prevention). ### What does "exempt from registration" actually mean? It means a safety judgment about the ingredients, and no effectiveness judgment about the product. EPA's own wording: "In the 1990s, EPA evaluated the active ingredients in these unregistered products for safety. We determined that the active ingredients posed minimal risk to human health in the percentages found in products on the market ... Note that products made from these ingredients have not been evaluated for effectiveness." The ingredients EPA names as examples used in unregistered repellents are citronella oil, cedar oil, geranium oil, peppermint and peppermint oil, and soybean oil. Citronella and citronella oil both appear on [EPA](https://www.epa.gov/sites/default/files/2015-12/documents/minrisk-active-ingredients-tolerances-2015-12-15.pdf)'s list of active ingredients eligible for minimum risk pesticide products under 40 CFR 152.25(f). EPA adds that repellents without a registration number "have not been evaluated by EPA, and EPA cannot advise consumers about the effectiveness of these products." One knock-on effect shows up on shelves: exempt labels cannot link a pest to a disease. Per EPA, such a label "may not say: 'controls ticks that carry Lyme disease;'" but can say "controls ticks." ### Why does the CDC say no OLE or PMD under age 3? p-Menthane-3,8-diol, the active component of oil of lemon eucalyptus, is the exception to the volatility problem, and it still carries an age restriction. [EPA](https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-011550_01-Apr-00.pdf) describes it as "a biochemical pesticide derived from eucalyptus plants" that "occurs naturally in the lemon eucalyptus plant," though "for commercial use, the active ingredient is chemically synthesized." The Malaria Journal review explains why it lasts: PMD "has a lower vapour pressure than volatile monoterpines found in most plant oils and provides very high protection from a broad range of insect vectors over several hours." The restriction is specific and appears on both CDC prevention pages: "Do not use products containing OLE or PMD on children under 3 years old." The CDC Yellow Book gives the reason and one more warning in a single sentence. CDC "does not recommend using 'pure' oil of lemon eucalyptus (an essential oil that is not formulated) as a repellent because it has not undergone validated testing for safety and efficacy and is not registered with EPA as an insect repellent; in general, parents should not use products containing OLE or PMD on children <3 years old to avoid potential allergic skin reactions." The bottle matters as much as the plant. A registered OLE repellent and a bottle of lemon eucalyptus essential oil are not the same product. ### Do citronella wristbands and patches work? The controlled tests are unkind to wearables. A semi-field study in Israel released 1,500 *Aedes albopictus* or 1,500 *Culex pipiens* into mesh-enclosed greenhouses and tested seven products, among them a wristband with 22 percent citronella oil and an oil of lemon eucalyptus adhesive patch. Result: "the sticker, transdermal patch, wristbands and sonic device did not provide significant protection to volunteers compared with the mosquito attack rate on control volunteers." The CDC Yellow Book puts it in one line: wearing "repellent-impregnated wristbands" is ineffective. ### What if a plant-oil repellent irritates your skin? Plant does not mean gentle. [NPIC](http://npic.orst.edu/factsheets/citronellagen.html) notes that oil of citronella "can be mildly irritating to the skin and eyes" and "may also cause skin allergies for some people with prolonged or frequent exposure," and that "some oil of citronella products should not be used on children less than six months old unless directed by a doctor." CDC's instruction if a reaction happens: wash the product off with mild soap and water, stop using it, and bring the container if you seek care. Any decision about a rash or a reaction in a child belongs with your clinician. For bites, see [bite treatment](https://longsleeve.com/blog/mosquito-bite-treatment). ### Where Longsleeve fits Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with [nine disclosed ingredients](https://longsleeve.com/ingredients). ### Common questions **How long do citronella candles protect you?** Published trials report reduction in biting, not a protection window. A field study in Guelph, Ontario, published in 1996, measured a 42.3 percent overall reduction from 3 percent citronella candles . An indoor Israeli trial measured 29.0 percent repellency for 5 percent citronella candles, and outdoors repellency dropped significantly as distance rose past 1 m. **Is oil of lemon eucalyptus the same as lemon eucalyptus essential oil?** No. CDC "does not recommend using 'pure' oil of lemon eucalyptus (an essential oil that is not formulated) as a repellent because it has not undergone validated testing for safety and efficacy and is not registered with EPA as an insect repellent." EPA lists oil of lemon eucalyptus among active ingredients in registered skin-applied repellents, noting it contains PMD but is a separately regulated pesticide chemical. **Does a missing EPA registration number mean a repellent does not work?** It means nobody at EPA checked. EPA says products made from exempt ingredients "have not been evaluated for effectiveness," and that repellents without a registration number "have not been evaluated by EPA, and EPA cannot advise consumers about the effectiveness of these products." Some exempt formulations do well in individual studies; no agency review stands behind them. **Does the EPA say citronella candles repel mosquitoes?** Yes, as a category. EPA's 1999 citronella fact sheet lists candles among oil of citronella repellent products and says those products, "which vary in efficacy," repel mosquitoes, biting flies and fleas, with repellency time varying by the inert ingredients and the amount of citronella oil. In its 1997 reregistration decision EPA examined efficacy data for oil of citronella lotion products and found reasonable effectiveness lasts 1 to 2 hours on average. That figure describes lotions, not candles. **Are citronella candles EPA registered?** It depends on what else is in the product. EPA 's citronella fact sheet says some citronella products are exempt from the usual regulation, and registration is required for products that miss the exemption criteria, for instance by containing other ingredients EPA has not classified as minimal risk. A product that meets all six of EPA's minimum risk conditions does not need to be registered at all; other plant-derived actives that are registered sit on the other side of that line. **Do citronella plants keep mosquitoes away?** Not in the two published trials that tested it. The "mosquito plant" sold as citrosa, Pelargonium citrosum, is a Pelargonium, not one of the Cymbopogon grasses EPA says oil of citronella is distilled from: a 1996 study in the Journal of the American Mosquito Control Association detected no character of a citronella-oil Cymbopogon in it and no significant difference in biting between citrosa-treated and untreated subjects. A 1994 study in the same journal found no significant difference in mosquito landings on subjects' forearms with or without the plants. For what does help, see keeping mosquitoes away from a patio dinner . ### Related reading - [Natural Bug Repellents: What the Evidence Supports](https://longsleeve.com/blog/natural-repellents). Registered plant-derived actives, the exemption loophole, and the study data. - [Do Bug Zappers Work on Mosquitoes?](https://longsleeve.com/blog/bug-zappers). Two field studies counted the catch. Mosquitoes were 0.22 and 0.37 percent of it. - [Why mosquitoes bite some people more](https://longsleeve.com/blog/why-mosquitoes-bite-some-people). Carbon dioxide, skin odor, and the explanations research has refuted. - [When is tick season?](https://longsleeve.com/blog/tick-season-when) The calendar beats the thermometer. - [West Nile virus in the United States](https://longsleeve.com/blog/west-nile-virus). The leading cause of mosquito-borne disease in the contiguous United States. - [Our almanac of mosquitoes and ticks](https://longsleeve.com/facts). Species, ranges, and the diseases they carry. - [Do Ultrasonic Repellers Work?](https://longsleeve.com/blog/ultrasonic-repellers). What controlled trials found about the electronic ones. More Longsleeve in your Google feed: ### Sources 1. EPA, Skin-Applied Repellent Ingredients. [https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients) 1. EPA, Regulation of Skin-Applied Repellents. [https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents](https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents) 1. EPA, Conditions for Minimum Risk Pesticides. [https://www.epa.gov/minimum-risk-pesticides/conditions-minimum-risk-pesticides](https://www.epa.gov/minimum-risk-pesticides/conditions-minimum-risk-pesticides) 1. EPA, Active Ingredients Eligible for Minimum Risk Pesticide Products (December 2015). [https://www.epa.gov/sites/default/files/2015-12/documents/minrisk-active-ingredients-tolerances-2015-12-15.pdf](https://www.epa.gov/sites/default/files/2015-12/documents/minrisk-active-ingredients-tolerances-2015-12-15.pdf) 1. EPA, p-Menthane-3,8-diol (011550) Fact Sheet Summary. [https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-011550_01-Apr-00.pdf](https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-011550_01-Apr-00.pdf) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC, Preventing Tick Bites. [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. CDC, About West Nile Virus. [https://www.cdc.gov/west-nile-virus/about/index.html](https://www.cdc.gov/west-nile-virus/about/index.html) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. Eisen L. Efficacy of Unregulated Minimum Risk Products to Kill and Repel Ticks. Emerging Infectious Diseases, 2024;30(1). [https://wwwnc.cdc.gov/eid/article/30/1/23-0813_article](https://wwwnc.cdc.gov/eid/article/30/1/23-0813_article) 1. NPIC, Oil of Citronella Fact Sheet. [http://npic.orst.edu/factsheets/citronellagen.html](http://npic.orst.edu/factsheets/citronellagen.html) 1. Maia MF, Moore SJ. Plant-based insect repellents: a review of their efficacy, development and testing. Malaria Journal, 2011;10(Suppl 1):S11. [https://pmc.ncbi.nlm.nih.gov/articles/PMC3059459/](https://pmc.ncbi.nlm.nih.gov/articles/PMC3059459/) 1. Lindsay LR, Surgeoner GA, Heal JD, Gallivan GJ. Evaluation of the efficacy of 3% citronella candles and 5% citronella incense for protection against field populations of Aedes mosquitoes. Journal of the American Mosquito Control Association, 1996;12(2 Pt 1):293-4. [https://pubmed.ncbi.nlm.nih.gov/8827606/](https://pubmed.ncbi.nlm.nih.gov/8827606/) 1. Müller GC, Junnila A, Kravchenko VD, et al. Indoor protection against mosquito and sand fly bites: a comparison between citronella, linalool, and geraniol candles. Journal of the American Mosquito Control Association, 2008;24(1):150-3. [https://pubmed.ncbi.nlm.nih.gov/18437831/](https://pubmed.ncbi.nlm.nih.gov/18437831/) 1. Müller GC, Junnila A, Butler J, et al. Ability of essential oil candles to repel biting insects in high and low biting pressure environments. Journal of the American Mosquito Control Association, 2008;24(1):154-60. [https://pubmed.ncbi.nlm.nih.gov/18437832/](https://pubmed.ncbi.nlm.nih.gov/18437832/) 1. Fradin MS, Day JF. Comparative efficacy of insect repellents against mosquito bites. New England Journal of Medicine, 2002;347(1):13-18. [https://pubmed.ncbi.nlm.nih.gov/12097535/](https://pubmed.ncbi.nlm.nih.gov/12097535/) 1. Kongkaew C, Sakunrag I, Chaiyakunapruk N, Tawatsin A. Effectiveness of citronella preparations in preventing mosquito bites: systematic review of controlled laboratory experimental studies. Tropical Medicine and International Health, 2011;16(7):802-10. [https://pubmed.ncbi.nlm.nih.gov/21481108/](https://pubmed.ncbi.nlm.nih.gov/21481108/) 1. Revay EE, Junnila A, Xue RD, et al. Evaluation of commercial products for personal protection against mosquitoes. Acta Tropica, 2013;125(2):226-30. [https://pubmed.ncbi.nlm.nih.gov/23092689/](https://pubmed.ncbi.nlm.nih.gov/23092689/) 1. Rodriguez SD, Chung HN, Gonzales KK, et al. Efficacy of some wearable devices compared with spray-on insect repellents for the yellow fever mosquito, Aedes aegypti (L.) (Diptera: Culicidae). Journal of Insect Science, 2017;17(1):24. [https://pubmed.ncbi.nlm.nih.gov/28423421/](https://pubmed.ncbi.nlm.nih.gov/28423421/) 1. EPA, Citronella (Oil of Citronella) (021901) Fact Sheet, November 1999 (PDF). [https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-021901_01-Nov-99.pdf](https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-021901_01-Nov-99.pdf) 1. EPA, Reregistration Eligibility Decision (RED): Oil of Citronella, May 1997 (PDF). [https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/red_PC-021901_30-May-97.pdf](https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/red_PC-021901_30-May-97.pdf) 1. EPA, R.E.D. FACTS: Oil of Citronella, EPA-738-F-97-002, February 1997 (PDF). [https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/fs_PC-021901_1-Feb-97.pdf](https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/fs_PC-021901_1-Feb-97.pdf) 1. Matsuda BM, Surgeoner GA, Heal JD, Tucker AO, Maciarello MJ. Essential oil analysis and field evaluation of the citrosa plant "Pelargonium citrosum" as a repellent against populations of Aedes mosquitoes. Journal of the American Mosquito Control Association, 1996;12(1):69-74. [https://pubmed.ncbi.nlm.nih.gov/8723261/](https://pubmed.ncbi.nlm.nih.gov/8723261/) 1. Cilek JE, Schreiber ET. Failure of the "mosquito plant", Pelargonium x citrosum 'van Leenii', to repel adult Aedes albopictus and Culex quinquefasciatus in Florida. Journal of the American Mosquito Control Association, 1994;10(4):473-6. [https://pubmed.ncbi.nlm.nih.gov/7707049/](https://pubmed.ncbi.nlm.nih.gov/7707049/) Last reviewed 2026-08-06 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Cutter Lemon Eucalyptus Insect Repellent](https://longsleeve.com/repellent-index/cutter-lemon-eucalyptus-insect-repellent) or [OFF! Botanicals Insect Repellent I](https://longsleeve.com/repellent-index/off-botanicals-insect-repellent-i). ## DEET Safety: What EPA and CDC Reviews Actually Found URL: https://longsleeve.com/blog/deet-safety-evidence > DEET carries EPA registration, a Group D cancer class (not classifiable as a human carcinogen), and EPA findings of no health concern with normal use. Source: https://longsleeve.com/blog/deet-safety-evidence By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 16, 2026 · Updated September 13, 2026 **Short answer:** DEET has been in public use since 1957. EPA reassessments in 1998 and 2014 concluded that normal use does not present a health concern to the general population, including children. Reported effects are most often eye irritation and skin irritation. CDC guidance still says to use EPA-registered repellents as directed and to follow the product label. ### How long has DEET been in use, and how many people use it? The chemical name is N,N-diethyl-meta-toluamide. The EPA says the U.S. Army developed it in 1946 and that it was registered for use by the general public in 1957. The EPA estimates about one-third of the U.S. population uses DEET every year, and NPIC puts the figure at about 30 percent. Formulations registered for direct application to human skin contain from 5 to 99 percent DEET. In the [EPA](https://www.epa.gov/insect-repellents/deet)'s words, "Rather than killing them, DEET works by making it hard for these biting bugs to smell us." ### What did the EPA conclude when it reregistered DEET in 1998? Pesticides first registered before November 1984 had to be reregistered against newer standards. The [EPA](https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/fs_PC-080301_1-Apr-98.pdf) finished that review in April 1998, and was specific: "In studies using laboratory animals, DEET generally has been shown to be of low acute toxicity. It is slightly toxic by the eye, dermal and oral routes and has been placed in Toxicity Category III (the second lowest of four categories) for these effects." The conclusion: DEET "generally is of low acute toxicity, and, based on the available toxicological data, the Agency believes that the normal use of DEET does not present a health concern to the general U.S. population." The human risk assessment "identified no toxicologically significant effects in animal studies," and the agency classified DEET as "a Group D carcinogen (not classifiable as a human carcinogen.)" Conditions came with it. Every product had to carry a series of 14 statements covering application method, precautions for children and directions for medical attention. Child-safety claims had to come off every end-use label, because the agency called them "misleading and irreconcilable with the intended use and pesticidal ingredients of DEET products." Separately, it wrote that "there appears to be no correlation between the percent active ingredient in the product and its safety." ### What did the 2014 review add? The EPA revisited DEET under Registration Review and posted an Interim Decision on September 24, 2014. The findings were narrow: "no additional data are required at this time" and "no changes to the affected registrations or their labeling are needed at this time." The human health risk assessment "concluded that there are no risks of concern because no toxic effects have been identified when used as a dermally applied insect repellent." One piece is unfinished. A final decision on the registration review case "will occur only after the EPA has completed an Endocrine Disruptor Screening under FFDCA section 408(p)," and the agency says DEET sits lower on the screening priority list than chemicals currently being tested. [NPIC](https://npic.orst.edu/factsheets/archive/DEETtech.html)'s archived technical sheet reported that no data were found on endocrine effects from DEET exposure, and none on chronic health effects in humans. ### Is DEET banned anywhere? In the United States, DEET holds EPA registration: the agency says approximately 120 products containing DEET are currently registered with the EPA by about 30 different companies, and, except for a few veterinary uses, that registration is for use by consumers. The EPA says most skin-applied repellents must be registered by the agency before they can be marketed, and that it reviews each registered pesticide at least every 15 years. Health Canada's direction on DEET runs by concentration and age, and Health Canada says only government approved products are allowed for use in Canada. Health Canada gives the right concentration of DEET as up to 30 percent for adults and children older than 12, up to 10 percent for children aged 2 to 12, and up to 10 percent, no more than once a day, for children aged 6 months to 2 years. Health Canada also says not to use a DEET product daily for more than a month on children younger than 12, and not to use a DEET repellent on infants younger than 6 months, with a mosquito net over the crib or stroller outdoors instead. The U.S. age guidance is in [repellents for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). ### Does DEET cause cancer? The EPA's answer is a classification. In the 1998 RED, the agency's RfD Peer Review Committee recommended that DEET be classified as "Group D (i.e., not classifiable as a human carcinogen) because the mouse and rat carcinogenicity studies did not demonstrate any carcinogenic potential". The RED defines the category in the next sentence: "A Group D classification is generally used for agents with inadequate human and animal evidence of carcinogenicity or for which no data are available." On the evidence itself, the RED says that although some minor effects were seen at the doses tested, "the data do not show DEET to be carcinogenic, significantly developmentally toxic, nor mutagenic." NPIC's archived technical fact sheet carries two of the studies behind that: mice fed 250, 500 or 1,000 mg/kg per day for 18 months and dogs fed 30, 100 or 400 mg/kg per day, with no specific target organ toxicity or oncogenicity observed in any of the animals. It also says sufficient evidence indicates DEET does not have significant potential for mutagenicity. NPIC stopped producing technical fact sheets in 2011 and says the archive may contain out-of-date material, so the RED wording above is the one to quote. ### Is DEET neurotoxic? The [EPA](https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/red_PC-080301_1-Apr-98.pdf)'s finding, from the committee that set DEET's toxicity endpoints for the 1998 RED, is that "the observed toxicological effects from laboratory data are not toxicologically significant with respect to the labeled use of DEET." Because the reported incidents were seizures, that committee evaluated the whole toxicology database with emphasis on the acute and subchronic neurotoxicity screening studies, and determined that the possible effect seen in those two studies "was not robust enough to provide an adequate basis for risk assessment": a transient increase in horizontal activity at one dose, with no clinical signs or histopathological changes. The 2014 human health risk assessment quoted above then found no risks of concern for use as a dermally applied repellent. On seizures, the RED states that "the available data do not support a direct link between exposure to DEET and reported seizure incidences," and NPIC's archived sheet records that the EPA and the FIFRA Scientific Advisory Panel called the reported seizures among children potentially related to DEET use "inconclusive" and said they do not support a causal link. The case count, the deaths, the per-user rate and the EPA's refusal to close the question either way are set out below under "What do the documented adverse-effect reports actually show?" and are not repeated here. ### What does the NPIC toxicity summary say? [NPIC](https://npic.orst.edu/factsheets/DEETgen.html), a cooperative agreement between Oregon State University and the EPA, publishes a public DEET fact sheet. Products in the eyes may cause irritation, pain and watery eyes. People who have left DEET products on their skin for extended periods have experienced irritation, redness, rash and swelling. People who have swallowed them have experienced stomach upset, vomiting and nausea. On seizures the qualifier matters: "Very rarely, exposure to DEET has been associated with seizures in people. Most of these reactions have happened after drinking products with DEET in them or using the products in ways that do not follow label directions." NPIC's archived technical fact sheet carries the animal numbers behind the low-toxicity label: an acute oral LD50 in rats of 2,170 to 3,664 mg/kg and an acute dermal LD50 in rabbits of 4,280 mg/kg. ### What do the documented adverse-effect reports actually show? Two datasets dominate. The first is poison center reports, which NPIC's archived sheet summarizes for 1993 to 1997: symptoms depended on the pathway of exposure and were most frequently associated with ocular exposure, and dermal symptoms were reported in 5 percent of reports to poison control centers following DEET exposure. That is a share of reports, not a share of users. The second is the EPA's 1998 seizure record. The agency counted, since 1960, "14 cases of seizure, including four deaths, potentially related to DEET exposure, for which other more likely causes have not been identified," with another 32 cases reported to a national DEET registry then still under review, so the total would "fall between 14 and 46 cases since 1960," a range "subject to both over- and under-reporting." Against use, it wrote: "Given only 14 to 32 cases since 1960 (the first case was reported in 1961) and 50-80 million people using DEET each year, the observed incidence of recognized seizures is about one per 100 million users." The EPA did not claim the cases were caused by DEET, and it did not clear them either: "The Agency has analyzed these incidents and cannot, at this time, conclude that these seizures are directly related to DEET exposure. However, neither can the Agency definitely conclude that they are not DEET-related." It offered coincidence as one explanation, citing an estimated 15,000 to 20,000 afebrile seizures in children aged 0 to 19 annually and an estimated 17 million children using DEET perhaps as often as 10 times a year. The FIFRA Scientific Advisory Panel agreed the reported incidences were inconclusive. It tightened labels anyway, saying improved warnings were prudent for a chemical applied directly to skin and used so widely. The [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html)'s Yellow Book adds the clinical frame: "Severe reactions to insect repellents are rare." ### What does the CDC say about DEET and pregnancy? The CDC's mosquito bite prevention page points pregnant and breastfeeding women to EPA-registered repellents used as directed, and lists DEET among the active ingredients. Its Yellow Book adds that "Other than the safety tips listed above, EPA does not recommend any additional precautions for using registered repellents on children or on women who are pregnant or lactating." NPIC describes a double-blind, randomized trial testing DEET to prevent malaria in pregnancy: women in their second and third trimesters applied a product with 20 percent DEET to their arms and legs daily. DEET crossed the placenta and was detected in 8 percent of cord blood samples in that trial. No significant adverse effects were detected in mother or fetus, and infants showed no differences in development or survival at birth or at age one. Travel raises its own questions, covered in the [dengue travel guide](https://longsleeve.com/blog/dengue-travel). ### What is the guidance for children? The [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) approves DEET for use on children with no age restriction, and sets no restriction on the percentage for children, "since data do not show any difference in effects between young animals and adult animals in tests done for product registration." In 1998 it wrote that reproductive and developmental toxicity data gave no evidence that would lead it to believe the chemical was uniquely toxic to infants or children. The Yellow Book likewise says repellents containing DEET can be used on children without age restriction. Other bodies publish tighter numbers, worth seeing side by side. NPIC reports that the American Academy of Pediatrics has recommended that DEET not be used on children younger than 2 months, that it be applied no more than once a day for children older than two months, that products with the lowest concentration available be used, and that parents avoid children's hands, eyes and mouths. A [CDC](https://www.cdc.gov/parasites/media/pdfs/2024/05/repellents_2015.pdf) fact sheet for travelers says to use no more than 30 percent DEET on a child and not to put insect repellent on babies younger than 2 months. More on age rules in [repellents for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). ### How much DEET gets into the body? Some does. NPIC says that when DEET was applied to the skin of volunteers, a small amount was taken into the body, it can be found in the blood up to 12 hours after application, the liver breaks it down, it leaves mainly through the urine, and nearly all of it is eliminated within 24 hours. A few things raise absorption. NPIC reports that applying DEET with alcohol increases uptake compared with DEET alone, that drinking alcohol may also increase absorption, and that [sunscreen products containing DEET may cause more of it to be taken in through the skin](https://longsleeve.com/blog/bug-spray-and-sunscreen). NPIC also notes that people have had adverse reactions when they applied it under clothing, and that the amount absorbed may increase when treated skin is covered. Hence the label line "DO NOT USE UNDER CLOTHING." Treated fabric is a separate approach, covered in [permethrin-treated clothing](https://longsleeve.com/blog/permethrin-clothing). ### Common questions **Has the EPA ever found DEET to cause cancer?** No. The EPA classified DEET as a Group D carcinogen, meaning not classifiable as a human carcinogen. NPIC explains that this means there is not enough evidence to say that it does or does not cause cancer, and that researchers have not found evidence that it causes cancer in animals or humans. **How long does DEET keep bugs off?** The EPA says studies in its database indicate that DEET repels ticks for about two to ten hours, and mosquitoes from two to twelve hours, depending on the percentage in the product. The Yellow Book says studies suggest efficacy tends to peak around 50 percent, with higher concentrations not offering a marked increase in protection time against mosquitoes. **Does it affect sunscreen?** The Yellow Book says limited data show that DEET-containing repellents applied over sunscreen decrease the sunscreen's sun protection factor by one-third, and advises separate products, sunscreen first. **What should I do if I react to a repellent?** The EPA says to stop using the product, wash treated skin , and call your local poison control center or physician, taking the container with you if you see a doctor. **What are the side effects of DEET?** Eye irritation, skin irritation and stomach upset, by route of exposure, as set out above under the NPIC summary. The EPA's list of DEET label directions adds that use may cause skin reactions in rare cases. **Is DEET dangerous to humans?** The EPA's finding is that normal use does not present a health concern: after its re-assessment the agency "concluded that insect repellents containing DEET do not present a health concern," and after the 2014 review it wrote that it continues to believe the normal use of DEET does not present a health concern to the general population, including children. The condition is the label: the EPA says FIFRA requires pesticides to be used according to the approved label, and DEET labels tell you not to apply over cuts, wounds or irritated skin, not to apply to the hands or near the eyes and mouth of young children, and not to use the product under clothing. How DEET and picaridin line up on the agency record is in picaridin vs DEET ; if you are pregnant, start with mosquito repellent in pregnancy and take the question to your clinician. ### About Longsleeve Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients. None of this is medical advice. If you are pregnant, treating an infant, or dealing with a reaction to any product, talk to your clinician, and follow the label on whatever you use. ### Related reading - [Picaridin vs DEET: What the Sources Actually Say](https://longsleeve.com/blog/picaridin-vs-deet). Both actives, side by side, per EPA, CDC, AAP, and NPIC. - [Mosquito Repellent for Kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). What the age rules actually say, ingredient by ingredient. - [Permethrin-Treated Clothing](https://longsleeve.com/blog/permethrin-clothing). How treated fabric fits into bite prevention. - [Lyme Disease Prevention](https://longsleeve.com/blog/lyme-disease-prevention). What the CDC recommends before and after a tick bite. - [How to Remove a Tick](https://longsleeve.com/blog/tick-removal). The CDC-recommended procedure, step by step. - [The field guide](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. EPA, DEET. [https://www.epa.gov/insect-repellents/deet](https://www.epa.gov/insect-repellents/deet) 1. EPA, R.E.D. Facts: DEET, EPA-738-F-95-010, April 1998 (PDF). [https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/fs_PC-080301_1-Apr-98.pdf](https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/fs_PC-080301_1-Apr-98.pdf) 1. EPA, Reregistration Eligibility Decision (RED) for DEET, EPA738-R-98-010, approved April 13, 1998 (PDF). [https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/red_PC-080301_1-Apr-98.pdf](https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/red_PC-080301_1-Apr-98.pdf) 1. EPA, DEET Interim Registration Review Decision, Case Number 0002, posted September 24, 2014, docket EPA-HQ-OPP-2012-0162. [https://www.regulations.gov/document/EPA-HQ-OPP-2012-0162-0012](https://www.regulations.gov/document/EPA-HQ-OPP-2012-0162-0012) 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. NPIC, DEET General Fact Sheet. [https://npic.orst.edu/factsheets/DEETgen.html](https://npic.orst.edu/factsheets/DEETgen.html) 1. NPIC, DEET Technical Fact Sheet (archived). [https://npic.orst.edu/factsheets/archive/DEETtech.html](https://npic.orst.edu/factsheets/archive/DEETtech.html) 1. NPIC, Can I apply DEET under my clothes? [https://npic.orst.edu/faq/deet.html](https://npic.orst.edu/faq/deet.html) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. CDC, Insect Repellents Help Prevent Malaria and Other Diseases Spread by Mosquitoes (PDF). [https://www.cdc.gov/parasites/media/pdfs/2024/05/repellents_2015.pdf](https://www.cdc.gov/parasites/media/pdfs/2024/05/repellents_2015.pdf) 1. EPA, Regulation of Skin-Applied Repellents. [https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents](https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents) 1. EPA, Registration Review Process. [https://www.epa.gov/pesticide-reevaluation/registration-review-process](https://www.epa.gov/pesticide-reevaluation/registration-review-process) 1. Health Canada, Personal Insect Repellents, page date June 2, 2021. [https://www.canada.ca/en/health-canada/services/about-pesticides/insect-repellents.html](https://www.canada.ca/en/health-canada/services/about-pesticides/insect-repellents.html) Last reviewed 2026-08-16 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) or [Coleman 25% DEET Insect Repellent Dry Spray](https://longsleeve.com/repellent-index/coleman-25-deet-insect-repellent-dry-spray). ## Dengue and Travel: Day-Biting Mosquitoes and Warning Signs URL: https://longsleeve.com/blog/dengue-travel > CDC-sourced dengue travel guide: where risk is concentrated, why Aedes mosquitoes bite during the day, what severe dengue warning signs mean, and what to pack. Source: https://longsleeve.com/blog/dengue-travel By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 6, 2026 · Updated August 16, 2026 Dengue is spread by Aedes mosquitoes that bite during the day and at night, across the tropics and subtropics, and the CDC says about 4 billion people live in areas with risk. Before you go, check CDC travel notices, pack an EPA-registered repellent and acetaminophen, and learn the warning signs. Severe dengue is a medical emergency. Most travelers who pick up dengue never find out: the CDC puts it at about one in four infected people getting sick at all. The ones who do get sick can go from fever to hospital in hours, and the drug most people reach for is the wrong one. ### Where is dengue actually a risk? Broadly, the warm half of the world. The [CDC](https://www.cdc.gov/dengue/areas-with-risk/index.html): "Almost half of the world's population, about 4 billion people, live in areas with a risk of dengue." Transmission "is common in tropical and subtropical areas of the world," and outbreaks are reported frequently across the Americas, Africa, the Middle East, Asia, and the Pacific Islands, including popular tourist destinations. **Short answer:** Dengue is spread by infected *Aedes* mosquitoes that bite during the day and at night across the tropics and subtropics. CDC guidance says about 4 billion people live in areas with dengue risk. Before travel, check CDC travel notices, pack an EPA-registered repellent and acetaminophen, and know the warning signs of severe dengue. Severe dengue is a medical emergency. The traveler numbers are not small. The Yellow Book reports that during 2010 through 2021, a total of 7,528 travel-related dengue cases were reported in the United States; a total of 3,135 patients required hospitalization, and 19 died. A 2026 paper in the CDC journal Emerging Infectious Diseases notes 3,742 travel-associated cases were reported in 2024, far exceeding the previous peak of 1,474 cases in 2019. Where dengue runs hot changes month to month, so the CDC keeps a live travel notice. As of the July 2026 update it listed Bolivia, Cambodia, Colombia, Kenya, Malaysia, Maldives, New Caledonia, Samoa, Sri Lanka, Tonga, and Vietnam as countries "reporting higher than usual numbers of cases," or where [CDC](https://wwwnc.cdc.gov/travel/notices/level1/dengue-global) has found a higher-than-expected number of cases among U.S. travelers returning. The caveat matters: "Not all countries with dengue transmission are on this list." ### Why does the daytime-biting pattern change what you do? If your mosquito habits were built around dusk, dengue breaks them. The CDC states plainly that "*Aedes* species mosquitoes can bite during the day and night." The [WHO](https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue): "You can lower your risk of dengue by avoiding mosquito bites, especially during the day." The Yellow Book names the peak as "early morning and late afternoon." Per the Yellow Book, "almost all DENV transmission occurs through the bite of infected *Aedes* species mosquitoes, primarily *Aedes aegypti* and *Aedes albopictus*." Their living arrangements matter in a hotel room: "While *Aedes albopictus* mosquitoes live mainly outdoors, *Aedes aegypti* mosquitoes live indoors and outdoors," often in dark, cool places like closets and bathrooms. They also do not travel far. The CDC says these mosquitoes "don't fly long distances. In their lifetime, these mosquitoes will only fly a few blocks," and they "typically lay eggs in containers that hold water, like buckets, bowls, animal dishes, flowerpots, and vases." A few blocks of range plus container breeding means the [standing water](https://longsleeve.com/blog/standing-water-mosquito-control) where you are staying counts for more than the swamp across town. ### What are the symptoms, and when do they start? Most infections are quiet. The [CDC](https://www.cdc.gov/dengue/signs-symptoms/index.html): "About one in four people infected with dengue will get sick." The Yellow Book estimates 40 to 80 percent of dengue virus infections are asymptomatic. When illness shows up, fever leads. The CDC lists the most common symptom as fever with any of the following: aches and pains, including eye pain typically behind the eyes and muscle, joint, or bone pain; nausea; vomiting; rash; or any warning sign. Symptoms "usually begin within 2 weeks after being bitten by an infected mosquito," typically last 2 to 7 days, and most people recover after about a week. Early dengue looks like everything else. The CDC warns "mild symptoms of dengue can be confused with other illnesses that cause fever," and a blood test "is the only way to confirm the diagnosis." To tell an ordinary bite reaction from the start of an illness, see [mosquito bite treatment](https://longsleeve.com/blog/mosquito-bite-treatment). ### What are the warning signs of severe dengue? Memorize this part before you leave. The CDC: "About 1 in 20 people who get sick with dengue will develop severe dengue. Severe dengue can result in shock, internal bleeding, and death." Note the scope. That is 1 in 20 among people who got sick, not among everyone infected. The cruel twist is the timing. The CDC says warning signs usually begin in the 24 to 48 hours after the fever has gone away. People feel better and stop watching. The list: - Belly pain or tenderness - Vomiting, at least 3 times in 24 hours - Bleeding from the nose or gums - Vomiting blood, or blood in the stool - Feeling extremely tired or restless Any of those means go now: "Immediately go to a local clinic or emergency room." And: "Symptoms of dengue can become severe within a few hours. Severe dengue is a medical emergency." The CDC's travel notice says severe cases can involve "hemorrhage (uncontrolled bleeding), shock (seriously low blood pressure), organ failure, and death." Repeat travelers should not get complacent. There are four dengue viruses, and infection with one "confers long-term immunity to that virus but only short-lived protection against the other three." The Yellow Book: "the risk for severe dengue is greater during a second DENV infection, but severe dengue also can occur during the first or any subsequent infection." ### Why are ibuprofen and aspirin avoided when dengue is suspected? Because dengue can cause bleeding, and those drugs make bleeding worse. The WHO: "Non-steroidal anti-inflammatory medicines such as ibuprofen and aspirin should be avoided as they can increase the risk of bleeding." The Yellow Book tells clinicians to advise ambulatory patients "to avoid medications with anticoagulant properties, including aspirin (acetylsalicylic acid), aspirin-containing drugs, and other nonsteroidal anti-inflammatory drugs (e.g., ibuprofen)." The CDC's public guidance is blunt: "Take acetaminophen (also known as paracetamol outside of the US) to control fever and relieve pain. Do not take aspirin or ibuprofen!" Which is why it tells travelers to pack acetaminophen, since "these medications can be used to manage fever and body pain in case you get dengue." CDC guidance for [West Nile virus](https://longsleeve.com/blog/west-nile-virus) carries the same caution for anyone living in an area with dengue. Ask a clinician rather than self-medicating abroad. ### What does the CDC recommend before, during, and after a trip? **Before your trip.** Review country-specific travel recommendations, health notices, and warnings. Visit a travel clinic or your healthcare provider. Pack an Environmental Protection Agency registered insect repellent and acetaminophen. **During your stay.** "Stay in places with air conditioning and with window/door screens." "Use a bed net if air conditioned or screened rooms are not available or if sleeping outdoors." Wear long-sleeved shirts and long pants outdoors. See a healthcare provider if you develop a fever or symptoms of dengue. **After your trip.** The step travelers skip. The [CDC](https://www.cdc.gov/dengue/prevention/index.html): "Even if you do not feel sick, travelers returning from an area with risk of dengue should take steps to prevent mosquito bites for 3 weeks so they do not spread dengue to mosquitoes that could spread the virus to other people." On repellents, the CDC lists six active ingredients in EPA-registered products: DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, and 2-undecanone. It tells people to "look for an EPA registration number (EPA Reg. No.) on the insect repellent product label." The EPA is explicit: "EPA and the U.S. Government do not endorse any product or service." CDC travel guidance adds 0.5 percent permethrin for clothing and gear, never on skin. ### Is there a dengue vaccine for travelers? Not for U.S. travelers. The [CDC](https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/dengue.html) Yellow Book: "There are currently no dengue vaccines recommended for travelers in the United States." The only dengue vaccine currently available in the United States is recommended for children 9 through 16 with laboratory confirmation of a previous dengue infection who live in areas where dengue is common, and the CDC carries a notice that the manufacturer is discontinuing it. For everyone else: "The vaccine is not approved for use in U.S. travelers who are visiting but not living in an area where dengue is common." ### What if you get sick after you get home? Tell whoever sees you where you have been. The Yellow Book instructs clinicians to consider dengue in patients who develop symptoms within 14 days of returning from an endemic area. Then protect the people around you. The [CDC](https://www.cdc.gov/dengue/treatment/index.html): "During the first week of illness, dengue can be found in the blood. The virus can be passed from an infected person to a mosquito through mosquito bites." That is not theoretical. The CDC reports most dengue cases in the 49 continental U.S. states occur in travelers infected elsewhere, but that "limited local spread of dengue has been reported in Florida, Hawaii, Texas, Arizona, and California." For mild illness its advice is rest, acetaminophen, and fluids. Decisions about testing or treatment belong with your clinician. ### Where Longsleeve fits Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with [nine disclosed ingredients](https://longsleeve.com/ingredients). ### Common questions **What are the odds of getting seriously ill from dengue?** The CDC says about one in four people infected with dengue will get sick, and about 1 in 20 people who get sick will develop severe dengue. That second number applies to people who became ill, not to everyone infected. Severe dengue can result in shock, internal bleeding, and death. **When during the illness does dengue get dangerous?** Usually right after you start feeling better. The CDC says warning signs typically begin in the 24 to 48 hours after the fever has gone away. Belly pain, repeated vomiting, bleeding from the nose or gums, blood in vomit or stool, or extreme tiredness or restlessness all mean go to a clinic or emergency room now. **Can I take ibuprofen for the aches?** Not if dengue is suspected. The CDC says to take acetaminophen, also known as paracetamol outside the United States, and not to take aspirin or ibuprofen. The WHO explains why: NSAIDs such as ibuprofen and aspirin can increase the risk of bleeding. Ask a clinician before taking anything. **Do I need to do anything after I get home?** Yes. The CDC says travelers returning from an area with risk of dengue should prevent mosquito bites for 3 weeks, even if they feel fine, so they do not pass the virus to local mosquitoes. ### Related reading - [Aedes aegypti: The Yellow Fever Mosquito](https://longsleeve.com/blog/aedes-aegypti). The day-biting container breeder behind dengue and Zika. - [Malaria Prevention for Travelers](https://longsleeve.com/blog/malaria-prevention-travelers). The Yellow Book's map, the drugs, and how bite protection fits. - [The Asian tiger mosquito](https://longsleeve.com/blog/asian-tiger-mosquito). One of the two Aedes species behind dengue, and a daytime biter. - [Standing water and mosquito control](https://longsleeve.com/blog/standing-water-mosquito-control). Container breeding is the whole Aedes life cycle. - [Why mosquitoes bite some people more](https://longsleeve.com/blog/why-mosquitoes-bite-some-people). What actually draws them, and what does not. - [Our species field guide](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. CDC, About Dengue. [https://www.cdc.gov/dengue/about/index.html](https://www.cdc.gov/dengue/about/index.html) 1. CDC, Symptoms of Dengue and Testing. [https://www.cdc.gov/dengue/signs-symptoms/index.html](https://www.cdc.gov/dengue/signs-symptoms/index.html) 1. CDC, How Dengue Spreads. [https://www.cdc.gov/dengue/transmission/index.html](https://www.cdc.gov/dengue/transmission/index.html) 1. CDC, Preventing Dengue. [https://www.cdc.gov/dengue/prevention/index.html](https://www.cdc.gov/dengue/prevention/index.html) 1. CDC, Manage Dengue. [https://www.cdc.gov/dengue/treatment/index.html](https://www.cdc.gov/dengue/treatment/index.html) 1. CDC, Areas with Risk of Dengue. [https://www.cdc.gov/dengue/areas-with-risk/index.html](https://www.cdc.gov/dengue/areas-with-risk/index.html) 1. CDC, Data and Statistics on Dengue in the United States. [https://www.cdc.gov/dengue/data-research/facts-stats/index.html](https://www.cdc.gov/dengue/data-research/facts-stats/index.html) 1. CDC, About a Dengue Vaccine. [https://www.cdc.gov/dengue/vaccine/index.html](https://www.cdc.gov/dengue/vaccine/index.html) 1. CDC Yellow Book, Dengue. [https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/dengue.html](https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/dengue.html) 1. CDC Travelers' Health, Global Dengue travel health notice. [https://wwwnc.cdc.gov/travel/notices/level1/dengue-global](https://wwwnc.cdc.gov/travel/notices/level1/dengue-global) 1. CDC Travelers' Health, Avoid Bug Bites. [https://wwwnc.cdc.gov/travel/page/avoid-bug-bites](https://wwwnc.cdc.gov/travel/page/avoid-bug-bites) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC, Life Cycle of Aedes Mosquitoes. [https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html](https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html) 1. CDC, About West Nile. [https://www.cdc.gov/west-nile-virus/about/index.html](https://www.cdc.gov/west-nile-virus/about/index.html) 1. Rysava K, Madewell ZJ, Thayer MB, et al. Using Routine Surveillance Data to Assess Dengue Virus Transmission Risk in Travelers Returning to the United States. Emerging Infectious Diseases, 2026;32(2). [https://wwwnc.cdc.gov/eid/article/32/2/25-1217_article](https://wwwnc.cdc.gov/eid/article/32/2/25-1217_article) 1. WHO, Dengue and severe dengue fact sheet. [https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue](https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) Last reviewed 2026-08-06 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Does Bug Spray Expire? What EPA Label Rules Actually Say URL: https://longsleeve.com/blog/does-bug-spray-expire > Purdue says pesticide makers generally design products to stay stable at least two to three years sealed. EPA's label rule and how to spot a bad bottle. Source: https://longsleeve.com/blog/does-bug-spray-expire By [Andrew Rothaus](https://longsleeve.com/about), Founder · September 9, 2026 · Updated October 1, 2026 **Short answer:** Bug spray with an EPA registration number is a registered pesticide product, and Purdue University's Pesticide Programs says pesticide makers generally design their formulations to stay stable for at least two to three years in the original, sealed package. A printed date is the exception: Purdue says U.S. pesticide makers generally do not print one, and federal rules require one only where a formulation is determined to change chemical composition significantly. ### Does bug spray have an expiration date at all? Only when EPA has determined the formulation changes chemical composition significantly, and the reason is one conditional sentence in federal pesticide labeling law. The rule at 40 CFR 156.10 reads: "In cases where it is determined that a pesticide formulation changes chemical composition significantly, the product must bear the following statement in a prominent position on the label: 'Not for sale or use after [date].'" That determination is the trigger. No such requirement applies otherwise, which is why a bottle can show an EPA Reg. No. and no date. When a date is printed, it means something specific: the same section says the product must meet all label claims up to the expiration time indicated on the label. What every registered repellent shows instead is a registration number and a storage block. The label must carry its registration number preceded by "EPA Registration No." or "EPA Reg. No.", and its storage and disposal instructions must be grouped under the heading "Storage and Disposal." ### What does EPA test before a repellent goes on sale? Storage stability, and it is not optional. EPA's product chemistry data requirements table at 40 CFR 158.310 lists test guideline 830.6317, storage stability, with an R for both MP and EP. In the table's key, R means required, MP means manufacturing-use product and EP means end-use product. [EPA](https://archive.epa.gov/oppfead1/cb/csb_page/updates/2012/web/html/storage-stab.html)'s 2012 news story describes the study it streamlined as a one-year study required to fulfill the agency's data requirements for pesticide registration and re-evaluation. EPA's accelerated alternative tests pesticides at an elevated temperature of 54 degrees C, which EPA said makes it unsuitable for some products and materials. If a 14-day study demonstrates product instability, a full one-year study is required. [Purdue University's Pesticide Programs](https://ag.purdue.edu/department/extension/ppp/resources/ppp-publications/mobile/ppp-1421.html), in a bulletin written for pesticide applicators, puts it plainly: the concentration of the active ingredient must remain stable when stored under conditions that simulate two years of real-time aging, and EPA requires the product to remain physically stable for two years, meaning it does not irreversibly clump or separate. Those are Purdue's words, not an EPA statement. ### How long is bug spray good for? Purdue's figure for pesticides is at least two to three years sealed, and after that it depends on storage. Its bulletin says manufacturers generally design their formulations to remain chemically and physically stable for at least two to three years in their original, sealed packages, and that this period in general becomes the unofficial expiration and warranty date for most pesticides. Past that window there is no set time for long-term stability, Purdue says, because storage conditions greatly influence how fast a product degrades. What it depends on, per Purdue: formulation, active ingredient, age, storage conditions, and whether the container remained sealed or was opened. Purdue also separates two terms people blur. Purdue says manufacturers set expiration dates, and that an expiration date tells you a properly stored product will perform as expected if you use it before that date. Shelf life, in Purdue's terms, is how long the product will remain effective after its expiration date and warranty have passed. ### What do repellent makers say about shelf life? Three of the four makers below give a number, from three years to ten or more, and one gives none. Each is a company describing its own products. Ranger Ready says each lot is designed to be shelf stable for 3 years after manufacturing, and that the best-by date on the bottle tells you when to replace it. Proven says its repellent has no printed expiration date and recommends replacing it three years after opening. Sawyer says its insect repellents have a shelf life of 10 or more years when properly stored in a cool, dry location away from direct UV exposure, and that opening the bottle has no effect on shelf life. OFF! says most of its products do not have an expiration date and can be used as long as the container looks to be in good shape and has not been stored in extreme cold or heat. Separately, a University of Florida IFAS pesticide blog says that as a general rule of thumb, most manufacturers of pesticides recommend using a pesticide within 2 to 3 years of manufacture, and that storage conditions, product type, and whether it has been opened can greatly influence that. Shelf life is about the bottle. How long a repellent keeps working once it is on your skin is a separate question, covered in [how long picaridin lasts](https://longsleeve.com/blog/how-long-does-picaridin-last). ### Does bug spray work after the expiration date? Possibly, and Purdue's Pesticide Programs bulletin is blunt about the uncertainty: a pesticide product used beyond its expiration date may or may not be less effective. It has not necessarily degraded to the point that it is no longer effective, and, in Purdue's words, there is no guarantee that it has not degraded. While the date was valid, the product had to meet all label claims up to the expiration time indicated on the label. [EPA](https://www.epa.gov/insect-repellents/find-repellent-right-you) notes that even between registered products, protection times vary because of differences in the testing conditions. Past the date, Purdue notes, manufacturers make no assurances or warranties about the quality of their products. ### How can you tell if bug spray has gone bad? Look at it, smell it, and turn it over a few times. Purdue's Pesticide Programs bulletin, written for pesticide applicators, says to see whether a product looks like it did when you first used it, and to assess the color, unusual odors, thickening, top-clearing, or noticeable sediment. Separation by itself is not a verdict. Purdue says that if the ingredients have separated, gently invert the closed container 5 to 10 times, and if the product remixes and appears uniform it may still be acceptable to use. The signs Purdue lists for considering disposal include clumping, accumulation at the bottom, a product that does not resuspend, an unusual odor or color, layers that remain separated after mixing, and hard-packed sediment. One cause of thickening, Purdue says, is evaporated solvent, which can make a product difficult to pour or cause particles to clump and clog nozzles. The date is the harder part. Where no date is printed, Purdue says, the age is hidden in lot codes that only the manufacturer can decipher, and it suggests writing the year of purchase on the container. If you have questions about whether a product is still good, Purdue says to contact the manufacturer's customer service information on the label. For a bottle whose age you cannot tell at all, [EPA](https://www.epa.gov/safepestcontrol/safe-disposal-pesticides) says to follow its advice on safe disposal, and to follow all disposal instructions on the pesticide label. ### What happens if you use expired insect repellent? Possibly a weaker product, or one that dispenses badly. Purdue's Pesticide Programs bulletin says a pesticide product used beyond its expiration date may or may not be less effective, and that products used beyond their shelf life may suffer dispensing problems, loss of potency, or spray application difficulties. Purdue's list is written for pesticide applicators generally, not for any particular can of repellent. The concern is performance. [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely)'s guidance for repellents is to read the product label before using it and to apply and re-apply according to the label instructions, with a warning: if you don't follow the label directions, the product may not be as effective as you expect. Storage directions are label directions too. ### Does bug spray go bad in heat or if it freezes? Yes, both. [NPIC](http://npic.orst.edu/health/storage.html), the National Pesticide Information Center, says extremes in temperature can change the chemistry of some pesticides inside the container. Heat is the case the testing anticipates. EPA's accelerated protocol tests pesticides at an elevated temperature of 54 degrees C. Separately, Purdue's bulletin puts the scale of heat aging in everyday terms: accelerated testing at 122 degrees F for two weeks normally predicts about two years of ambient storage stability. A trunk does not run a controlled two-week test; it runs all summer. Freezing is the case people forget. Purdue describes what can happen to a pesticide product subjected to freezing temperatures: the active ingredient could crystallize and fall out of suspension, settle to the bottom, and not resuspend when thawed and remixed. Purdue means pesticide formulations broadly, not any specific repellent. ### How long is bug spray good for once opened? The EPA and NPIC pages this article draws on give no after-opening window, and Purdue gives no fixed one. Purdue says that for a product still sealed in its original container and within two or three years of purchase, it seems like the answer is an easy yes, and that just the opposite is true for opened products beyond three years. It also lists a previously opened package among the signs to consider disposal. Purdue lists whether a container remained sealed or was opened as one factor among several, alongside formulation, active ingredient, age and storage conditions. ### Does DEET expire? Does picaridin? The expiration rule attaches to the finished product, not to the active ingredient in it. Products built on DEET or picaridin sit under the same 40 CFR 156.10 rule described above: a date only where the formulation is determined to change chemical composition significantly, and all label claims met up to any date that is printed. What the chemistry sources say is narrower than "does not expire." NPIC's technical fact sheets, in their environmental-fate sections, report that picaridin is stable to hydrolysis under environmentally relevant conditions, and that DEET, at soil pH levels typically found in the environment, is stable to hydrolysis. Those are environmental-fate findings, not shelf-life data for a bottle in a cabinet. [How long picaridin lasts on skin](https://longsleeve.com/blog/how-long-does-picaridin-last) once applied is a different question; the two actives side by side are at [picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet), and our [DEET evidence review](https://longsleeve.com/blog/deet-safety-evidence) covers what the EPA reviews say. For a specific branded DEET spray, the answer is on the can: find the EPA Reg. No., which the label must carry, then look for a "Not for sale or use after" line. ### Does the format matter: aerosol, pump, lotion or wipe? Yes, because the label time belongs to the product that carries it. EPA says an EPA registration number on a repellent label means the company provided EPA with technical information on the effectiveness of that product. EPA's repellency awareness graphic, where a product carries it, shows numbers that represent typical protection times, and those vary between products because of differences in the testing conditions. Sawyer compares formats within its own line. Sawyer's FAQ says that because of the way they slow down the evaporation of the product, [lotions will last approximately two hours longer than sprays](https://longsleeve.com/blog/picaridin-lotion-vs-spray) of comparable concentrations. That is Sawyer's statement about its own line. Where "how long does it last" means wash cycles on treated clothing, see our [permethrin clothing guide](https://longsleeve.com/blog/permethrin-clothing). ### How do you store repellent so it lasts? In the container it came in, with the label on, between 40 and 90 degrees F, away from anything that can ignite it, and out of reach of children. [EPA](https://www.epa.gov/safepestcontrol/storing-pesticides-safely) says to always store pesticides in their original containers with the label, which lists directions for use, ingredients, and first aid steps in case of accidental poisoning. NPIC adds that the original container is designed to protect the product and is made of materials that will withstand the chemicals in it. NPIC says to always read the label for storage instructions and, as a general rule, that pesticides are best stored between 40 and 90 degrees F. EPA adds that flammable liquids belong outside your living area and far away from an ignition source such as a furnace, car, grill or lawn mower. Check the [gear bin in the garage](https://longsleeve.com/blog/insect-repellent-for-hiking) against both. For households with children, EPA says to store insect repellents out of the reach of children, in a locked utility cabinet or garden shed. Our guide to [mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids) covers the age rules. ### How do you get rid of old bug spray? Follow the label first, then your local rules. EPA's disposal guidance opens with: follow all disposal instructions on the pesticide label. The Storage and Disposal block is where those live. For leftovers, both EPA and NPIC point to household hazardous waste. EPA says to check with your local solid waste management authority, environmental agency or health department for a household hazardous waste collection program or a similar program for unwanted, leftover pesticides. [NPIC](http://npic.orst.edu/health/disposal.html) is stricter: if any product remains in the container, it must be disposed of as household hazardous waste. EPA also notes that state and local pesticide disposal laws may be stricter than the federal requirements on the label. And the bottle you cannot place at all? EPA's storage guidance names two conditions: you can't identify the contents of the container, or you can't tell how old the contents are. For that bottle, the guidance above applies: the label's disposal instructions first, and household hazardous waste for anything left in it. ### Common questions **Is expired insect spray still usable?** Possibly, with no guarantee. Purdue's Pesticide Programs bulletin says a pesticide product used beyond its expiration date may or may not be less effective: it has not necessarily degraded to the point of being ineffective, and, in Purdue's words, there is no guarantee that it has not degraded. Past the date, you are using it on your own judgment. **Does bug spray go bad in the heat?** It can. NPIC says extremes in temperature can change the chemistry of some pesticides inside the container, and that as a general rule pesticides are best stored between 40 and 90 degrees F, with the label as the first place to check for storage instructions. A summer in a parked car sits well outside a cool, dry place. **How long is bug spray good for once opened?** The EPA and NPIC pages this article draws on give no after-opening window. Purdue gives no fixed one, but says that while a sealed product within two or three years of purchase seems like an easy yes, just the opposite is true for opened products beyond three years. Makers differ about their own products: Proven recommends replacing its repellent three years after opening, and Sawyer says opening the bottle has no effect on shelf life. **Can I throw old bug spray in the trash?** Not with product still in it. NPIC says that if any product remains in the container, it must be disposed of as household hazardous waste, and EPA says to check with your local solid waste management authority, environmental agency or health department for a household hazardous waste collection program. For an empty container, follow the label's Storage and Disposal block. **How do I know if bug spray is expired?** Check the label for a printed date first, though Purdue's Pesticide Programs says U.S. pesticide manufacturers generally do not print expiration dates on their containers. Without one, go by age and condition: Purdue says that for a product still sealed in its original container and within two or three years of purchase, it seems like the answer is an easy yes, and it lists an unusual odor or color, clumping, and layers that stay separated after mixing as signs to consider disposing of it. ### About Longsleeve Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. Its label's storage directions: store in a cool, dry place out of the reach of children, away from heat, sparks and open flame. ### Related reading - [How long does picaridin last?](https://longsleeve.com/blog/how-long-does-picaridin-last). Hours on skin and clothes; that post owns duration, this one owns expiry. - [Picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet). Duration, kids, ticks and materials, side by side. - [DEET: what the EPA reviews say](https://longsleeve.com/blog/deet-safety-evidence). The evidence record, which this article leaves alone. - [Permethrin-treated clothing](https://longsleeve.com/blog/permethrin-clothing). When "how long it lasts" means wash cycles, not hours. - [Insect repellent for hiking](https://longsleeve.com/blog/insect-repellent-for-hiking). Where the old bottle in the gear bin actually gets used. - [Mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). Age rules, and the out-of-reach storage line. - [Bug Spray and Sunscreen: Which Goes On First, How Long to Wait, and Why Not a Combo](https://longsleeve.com/blog/bug-spray-and-sunscreen). Sunscreen first, then repellent, and why not a combo. - [Can You Put Bug Spray on Your Face? Yes, Hands First, and Here Is Why the Label Says So](https://longsleeve.com/blog/bug-spray-on-face). Hands first, and what to do if it gets in your eyes. - [Bug Spray on Clothes or Skin? What Goes Where, What DEET Does to Synthetics, and How to Wash It Out](https://longsleeve.com/blog/bug-spray-on-clothes). What DEET does to synthetics, and how to wash it out. - [Should You Wash Off Bug Spray? What the Label Says About Bedtime, Hikes, and Kids](https://longsleeve.com/blog/wash-off-bug-spray). Before bed, after the hike, and on kids. ### Sources 1. eCFR, 40 CFR 156.10 Labeling requirements. [https://www.ecfr.gov/current/title-40/chapter-I/subchapter-E/part-156/subpart-A/section-156.10](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-E/part-156/subpart-A/section-156.10) 1. US EPA Label Review Manual, Chapter 13: Storage and Disposal (July 2013). [https://www.epa.gov/sites/production/files/2017-10/documents/chap-13-jul-2013.pdf](https://www.epa.gov/sites/production/files/2017-10/documents/chap-13-jul-2013.pdf) 1. eCFR, 40 CFR 158.310 Product chemistry data requirements table. [https://www.ecfr.gov/current/title-40/chapter-I/subchapter-E/part-158/subpart-D/section-158.310](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-E/part-158/subpart-D/section-158.310) 1. US EPA archived pesticide news story, New Protocol Streamlines Development of Storage Stability and Corrosion Characteristics Studies for Some Pesticides (November 30, 2012). [https://archive.epa.gov/oppfead1/cb/csb_page/updates/2012/web/html/storage-stab.html](https://archive.epa.gov/oppfead1/cb/csb_page/updates/2012/web/html/storage-stab.html) 1. Purdue University Pesticide Programs PPP-142, Is This Pesticide On My Shelf Still Good? [https://ag.purdue.edu/department/extension/ppp/resources/ppp-publications/mobile/ppp-1421.html](https://ag.purdue.edu/department/extension/ppp/resources/ppp-publications/mobile/ppp-1421.html) 1. Sawyer Products FAQs. [https://www.sawyer.com/faqs](https://www.sawyer.com/faqs) 1. US EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. US EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely](https://www.epa.gov/insect-repellents/using-insect-repellents-safely) 1. National Pesticide Information Center, Storage of Pesticides. [http://npic.orst.edu/health/storage.html](http://npic.orst.edu/health/storage.html) 1. US EPA, Storing Pesticides Safely. [https://www.epa.gov/safepestcontrol/storing-pesticides-safely](https://www.epa.gov/safepestcontrol/storing-pesticides-safely) 1. National Pesticide Information Center, Picaridin Technical Fact Sheet. [http://npic.orst.edu/factsheets/archive/Picaridintech.html](http://npic.orst.edu/factsheets/archive/Picaridintech.html) 1. National Pesticide Information Center, DEET Technical Fact Sheet. [http://npic.orst.edu/factsheets/archive/DEETtech.html](http://npic.orst.edu/factsheets/archive/DEETtech.html) 1. US EPA, Repellency Awareness Graphic. [https://www.epa.gov/insect-repellents/repellency-awareness-graphic](https://www.epa.gov/insect-repellents/repellency-awareness-graphic) 1. US EPA, Safe Disposal of Pesticides. [https://www.epa.gov/safepestcontrol/safe-disposal-pesticides](https://www.epa.gov/safepestcontrol/safe-disposal-pesticides) 1. National Pesticide Information Center, Disposal of Pesticides. [http://npic.orst.edu/health/disposal.html](http://npic.orst.edu/health/disposal.html) 1. University of Florida IFAS, Pesticide Information blog, Are My Pesticides Still Good? (May 26, 2022, updated April 6, 2026). [https://blogs.ifas.ufl.edu/pesticideinformation/2022/05/26/are-my-pesticides-still-good](https://blogs.ifas.ufl.edu/pesticideinformation/2022/05/26/are-my-pesticides-still-good) 1. Ranger Ready Repellents, FAQs. [https://rangerready.com/pages/faqs](https://rangerready.com/pages/faqs) 1. Proven Insect Repellent, FAQ. [https://provenrepellent.com/pages/faqs](https://provenrepellent.com/pages/faqs) 1. OFF! (S.C. Johnson), FAQs. [https://off.com/en-us/faq](https://off.com/en-us/faq) Last reviewed 2026-09-09 · every claim on this page is sourced above ## Ehrlichiosis: Symptoms, Lone Star Tick Link, and Treatment URL: https://longsleeve.com/blog/ehrlichiosis > CDC-sourced guide to ehrlichiosis symptoms, which ticks carry Ehrlichia bacteria, where cases occur, why early treatment matters, and how to reduce tick bites. Source: https://longsleeve.com/blog/ehrlichiosis By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 17, 2026 **Short answer:** Ehrlichiosis is the name for diseases caused by *Ehrlichia* bacteria, spread primarily through infected tick bites. The CDC says most reported U.S. cases are due to *E. chaffeensis*, carried by the lone star tick. Symptoms often include fever, chills, headache, muscle aches, and sometimes upset stomach. See a healthcare provider if you become ill after a tick bite or time in tick habitat. ### What is ehrlichiosis? Ehrlichiosis is the general name used to describe diseases caused in the United States by three bacteria: Ehrlichia chaffeensis, E. ewingii, or E. muris eauclairensis, according to the CDC. The agency notes that the majority of reported cases are due to infection with E. chaffeensis. These bacteria are spread to people primarily through the bite of infected ticks, including [the lone star tick](https://longsleeve.com/blog/lone-star-tick) (Amblyomma americanum) and the blacklegged tick (Ixodes scapularis). The New York State Department of Health adds a name you may see on lab paperwork: ehrlichiosis is also called human monocytic ehrlichiosis, or HME, and is spread to humans by lone star ticks infected with E. chaffeensis. The [CDC](https://www.cdc.gov/ehrlichiosis/causes/index.html) also notes that in rare cases, Ehrlichia species have been spread through blood transfusion and organ transplant. ### Which ticks carry ehrlichiosis? It depends on the species of bacteria. Per the CDC, E. chaffeensis and E. ewingii are carried by the [lone star tick](https://longsleeve.com/blog/lone-star-tick), found primarily in the south-central and eastern United States. A CDC MMWR report makes the same point from another angle, describing E. chaffeensis and E. ewingii as disease agents known to be transmitted by the lone star tick. Since E. chaffeensis accounts for the majority of reported cases, the lone star tick has a fair claim to this disease as its signature. The third species travels differently. Per the CDC, E. muris eauclairensis is carried by the blacklegged tick (Ixodes scapularis), and cases have only been reported from Wisconsin and Minnesota. The Minnesota Department of Health says people most likely get E. muris eauclairensis through the bite of an infected blacklegged tick, also called a deer tick. The department notes this species was first identified in 2009, and all patients described to date have reported likely blacklegged tick exposure in Minnesota or Wisconsin. One detail from the [CDC](https://www.cdc.gov/ehrlichiosis/signs-symptoms/index.html) worth sitting with: tick bites can be painless, and many people do not remember being bitten. ### What are the symptoms of ehrlichiosis? People with ehrlichiosis will often have fever, chills, headache, muscle aches, and sometimes upset stomach, according to the [CDC](https://www.cdc.gov/ehrlichiosis/about/index.html). Signs and symptoms typically begin within 1 to 2 weeks after the bite of an infected tick. The CDC describes early signs and symptoms, meaning the first 5 days of illness, as usually mild or moderate. They may include fever, chills, severe headache, muscle aches, nausea, vomiting, diarrhea, loss of appetite, confusion, and rash. The rash statistics come with careful scoping, so here they are exactly as the CDC frames them: up to 1 in 3 people with ehrlichiosis report a rash; rash is more common in people with E. chaffeensis ehrlichiosis and generally occurs more often in children than adults. The rash usually develops 5 days after fever begins, and it can look like red splotches or pinpoint dots. The CDC's advice at this stage is plain: see your healthcare provider if you become ill after being bitten by a tick or after spending time in grassy, brushy, or wooded areas. ### Why does early treatment matter? Because the cost of waiting can be steep. Per the CDC, if antibiotic treatment is delayed, ehrlichiosis can sometimes cause severe illness, and early treatment can reduce the risk of developing severe illness. The agency lists severe, late-stage outcomes that can include damage to the brain or nervous system such as meningoencephalitis, respiratory failure, uncontrolled bleeding, organ failure, and death. On treatment itself, we report what the agency says and nothing more. The [CDC](https://www.cdc.gov/ehrlichiosis/treatment/index.html) states that doxycycline is the treatment of choice for adults and children of all ages with ehrlichiosis, and that early treatment with the antibiotic doxycycline can prevent severe illness or death. CDC clinical guidance says doxycycline is most effective at preventing severe complications when it is started within the first week of illness, and that when ehrlichiosis is treated with doxycycline, fever "generally subsides" within 24 to 48 hours. The CDC advises speaking with a healthcare provider to learn about treatment for ehrlichiosis, and that conversation is the place for treatment decisions. The Minnesota Department of Health puts it just as directly: ehrlichiosis is treated with antibiotics, and treatment should not be delayed if ehrlichiosis is suspected. The CDC also flags who faces the highest risk of severe illness: people younger than 5 years old or older than 65, and people with weakened immune systems, such as those receiving some cancer treatments, individuals with advanced HIV infection, people who have received organ transplants, or people taking certain medications. ### How common is ehrlichiosis, and where? A 2016 study in the American Journal of Tropical Medicine and Hygiene analyzed national surveillance of E. chaffeensis ehrlichiosis from 2008 to 2012. It counted 4,613 reported cases, an incidence rate of 3.2 cases per million person-years. The severity figures from that same study are the reason this disease deserves respect: the hospitalization rate was 57%, the case fatality rate was 1%, and children under 5 had the highest case fatality rate at 4%. The study also recorded 55 cases of E. ewingii infection over the same period and noted that the overall reported rate of ehrlichiosis had increased 4-fold since 2000. The climb has continued. In CDC national data combining anaplasmosis and ehrlichiosis, reported cases rose from 875 in 2004 to 5,750 in 2016, with 39,959 cases reported over that 13-year period. On geography, the [CDC](https://www.cdc.gov/mmwr/volumes/67/wr/mm6717e1.htm)'s Vital Signs report describes ehrlichiosis, along with tularemia, as geographically widespread but more prevalent in the central United States. Per the CDC, ehrlichiosis caused by E. chaffeensis and E. ewingii is most frequently reported from the southeastern and south-central United States, from the East Coast extending westward to Texas. The Minnesota Department of Health describes the same pattern: human illness from E. chaffeensis and E. ewingii is most commonly reported from the southeastern and south-central United States, where the lone star tick is found. And the disease reaches farther north than many people expect. The New York State Department of Health reports that most New York cases have been reported on Long Island and in the Hudson Valley. ### How does the CDC say to prevent tick bites? There is no vaccine to prevent ehrlichiosis. The CDC says to prevent illness by preventing tick bites, preventing ticks on your pets, and preventing ticks in your yard. The agency calls reducing exposure to ticks the best defense against tickborne diseases, and notes that while tick exposure can occur year-round, ticks are most active during the warmer months, April through September. Our guide to [tick season by region](https://longsleeve.com/blog/tick-season-when) goes deeper on timing. Know where to expect ticks. Per the [CDC](https://www.cdc.gov/ticks/prevention/index.html), ticks live in grassy, brushy, or wooded areas, or on animals, and many people get ticks in their own yard or neighborhood. For personal protection, the CDC recommends: - Using EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone. - Treating clothing and gear with products containing 0.5% permethrin, which remains protective through several washings. Our [permethrin plus picaridin system](https://longsleeve.com/blog/permethrin-picaridin-system) covers how treated clothing and skin repellents work together. - Showering soon after being outdoors. Per the CDC, showering within two hours of coming indoors has been shown to reduce the risk of Lyme disease and may be effective in reducing the risk of other tickborne diseases. - Conducting a full body tick check upon return from potentially tick-infested areas, including your own backyard. A note on our own product, kept strictly to the label: Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance free, with nine disclosed ingredients. ### Frequently asked questions **Can you get ehrlichiosis more than once?** Yes. The New York State Department of Health says that even if successfully treated, a person may become re-infected if bitten later by another infected tick. **Is ehrlichiosis contagious from person to person?** No. The New York State Department of Health states that ehrlichiosis is not spread from person to person. **How is ehrlichiosis diagnosed?** The Minnesota Department of Health says diagnosis is based on a history of exposure to tick habitat, a physical examination, and laboratory tests to confirm the diagnosis. If you think you were exposed, that is a conversation for your healthcare provider. **Does removing a tick quickly lower the risk?** Per the New York State Department of Health, if an attached tick is removed within 36 hours, the risk of ehrlichiosis infection is minimal. Our guide to safe tick removal covers the mechanics. Last word, straight from the CDC: see your healthcare provider if you become ill after being bitten by a tick or spending time in grassy, brushy, or wooded areas. The agency's guidance keeps returning to the same point: an early conversation with a clinician. ### Related reading - [Lone Star Tick](https://longsleeve.com/blog/lone-star-tick). Identification, range, bites, and alpha-gal link. - [Alpha-Gal Syndrome Timeline](https://longsleeve.com/blog/alpha-gal-syndrome). How long after a tick bite symptoms start, and whether it goes away. - [How to Remove a Tick](https://longsleeve.com/blog/tick-removal). Tweezers, timing, and what not to do. - [Lyme Disease Prevention](https://longsleeve.com/blog/lyme-disease-prevention). Tick checks, repellent, permethrin, and removal. - [The species almanac](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. CDC, About Ehrlichiosis: [https://www.cdc.gov/ehrlichiosis/about/index.html](https://www.cdc.gov/ehrlichiosis/about/index.html) 1. CDC, Signs and Symptoms of Ehrlichiosis: [https://www.cdc.gov/ehrlichiosis/signs-symptoms/index.html](https://www.cdc.gov/ehrlichiosis/signs-symptoms/index.html) 1. CDC, Causes and Spread of Ehrlichiosis: [https://www.cdc.gov/ehrlichiosis/causes/index.html](https://www.cdc.gov/ehrlichiosis/causes/index.html) 1. CDC, Treatment of Ehrlichiosis: [https://www.cdc.gov/ehrlichiosis/treatment/index.html](https://www.cdc.gov/ehrlichiosis/treatment/index.html) 1. CDC, Clinical Care of Ehrlichiosis: [https://www.cdc.gov/ehrlichiosis/hcp/clinical-care/index.html](https://www.cdc.gov/ehrlichiosis/hcp/clinical-care/index.html) 1. CDC, Preventing Tick Bites: [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. CDC, Morbidity and Mortality Weekly Report, Vital Signs, 2018: [https://www.cdc.gov/mmwr/volumes/67/wr/mm6717e1.htm](https://www.cdc.gov/mmwr/volumes/67/wr/mm6717e1.htm) 1. CDC, Morbidity and Mortality Weekly Report, 2023: [https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a2.htm](https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a2.htm) 1. New York State Department of Health, Ehrlichiosis Fact Sheet: [https://www.health.ny.gov/diseases/communicable/ehrlichiosis/fact_sheet.htm](https://www.health.ny.gov/diseases/communicable/ehrlichiosis/fact_sheet.htm) 1. Minnesota Department of Health, About Ehrlichiosis: [https://www.health.state.mn.us/diseases/ehrlichiosis/basics.html](https://www.health.state.mn.us/diseases/ehrlichiosis/basics.html) 1. American Journal of Tropical Medicine and Hygiene, 2016, national surveillance of ehrlichiosis 2008 to 2012: [https://pmc.ncbi.nlm.nih.gov/articles/PMC4710445/](https://pmc.ncbi.nlm.nih.gov/articles/PMC4710445/) Last reviewed 2026-08-17 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Gnat Repellent: Biting Midges, Labels, Screens, and Fans URL: https://longsleeve.com/blog/gnat-repellent > How to choose gnat repellent when the biting gnats are midges: CDC label terms, DEET and picaridin guidance, EPA label rules, 20x20 mesh screens, and fans. Source: https://longsleeve.com/blog/gnat-repellent By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 26, 2026 The biting "gnats" that swarm your yard are usually biting midges, which Illinois DPH says are also called punkies, no-see-ums or simply gnats. IL DPH names DEET and picaridin as the actives to look for, and the CDC adds two force multipliers: 20x20 mesh screens and an outdoor fan. "Gnat" is the word people reach for when something small and infuriating is orbiting their head, and it covers several different insects. Which one you have determines what works, so start there. ### What are the gnats that are biting me? If they bite, they are most likely biting midges. The Illinois Department of Public Health puts it plainly: biting midges "are also known as 'punkies,' 'no-see-ums' or simply 'gnats,'" and they are so small, no more than 1/32 of an inch, that "their tiny size allows them to penetrate window and door screens." They are serious pests along the shores of oceans, lakes, ponds and rivers, and will bite during the day or at night. **Short answer:** Biting gnats are often biting midges, which Illinois DPH also calls punkies and no-see-ums. CDC guidance says to look for EPA-registered repellents labeled for flies, biting flies, or *Culicoides*. Illinois DPH names DEET and picaridin as actives to look for against biting flies, and CDC guidance adds two practical tools: 20x20 mesh screens and outdoor fans. ### What repellent works on biting gnats? Two answers, one from each agency lane. On actives, Illinois DPH: repellents "containing the active ingredient DEET (N,N-diethyl-meta-toluamide) or picaridin are best," with the honest caveat that repellents, while effective against mosquitoes, "have been found to be less effective against some types of biting flies," so they should be supplemented with other measures: avoiding the areas the flies inhabit, avoiding peak biting times, and wearing heavy-duty, light-colored clothing with long sleeves, long pants and hats. On labels, the [CDC](https://www.cdc.gov/oropouche/prevention/index.html)'s guidance for biting midges: "Look for EPA-registered repellents labeled for flies, biting flies, or *Culicoides* (biting midges, punkies, granny nippers, and no-see-ums)." The CDC also notes that when used as directed, EPA-registered insect repellents are proven safe and effective. A midge claim is registered pest by pest, so the product's own federal label is where the answer lives, and EPA's rule applies: always read the product label before using the product. We read those labels so you do not have to squint at 631 of them. [The Repellent Index](https://longsleeve.com/repellent-index) holds every EPA-registered skin-applied repellent with the pest claims on each product's federal label: 111 of the 631 carry a stated gnat protection time, and 47 a no-see-um time. The [statistics](https://longsleeve.com/repellent-index/statistics) and dataset are free. One more reading tip for the shelf: the phrasing on labels varies. The CDC's list of words to look for runs from the plain (flies, biting flies) to the taxonomic (Culicoides) to the regional nicknames (biting midges, punkies, granny nippers, no-see-ums). Any of those on a federal label is the claim you are looking for. None of them is implied by the word "mosquitoes." ### How do you apply it so it holds up? EPA's application rules, short version: read and follow the label directions and understand how much to apply; apply only to exposed skin and/or clothing, never under clothing. Gnat swarms go for any skin you left bare, so coverage of exposed skin matters more than a thick coat in one spot. ### What clears gnats out of a yard or porch? Two cheap physical tools, both agency-backed: - **A fan.** The CDC recommends using fans outdoors to help blow biting midges away, and Illinois DPH agrees: fans can keep small areas free of flies, "especially smaller flies whose flight is affected by air currents." Gnats are weak fliers. A box fan on the porch beats most gadgets sold for this job. - **Finer screens.** The CDC notes that many commonly used window and door screens do not have holes small enough to stop biting midges, and recommends looking for mesh screens measuring 20x20. If gnats show up inside a screened porch, the screen is the reason. Add the Illinois DPH basics, and the picture is complete: avoid the shoreline hours when the swarm is thickest, and put fabric between them and you. The department's clothing prescription for biting flies generally is heavy-duty and light-colored, long sleeves, long pants and hats, and it applies here for the simplest reason: skin that is covered does not need defending. What does not earn a place in the plan: anything that promises to clear a whole yard of gnats from a single point. The insects breeding along a shoreline are a population, not a visitor, and the agency guidance above never mentions a zapper or a sonic device. Moving air, finer mesh, covered skin and a labeled repellent are the tools with public health guidance behind them. Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours, and its accepted federal label carries the claim "Repels biting flies, stable flies, black flies, gnats, chiggers, sand flies and Scottish biting midges (no see-ums) for up to 8 hours." It is fragrance-free, with nine disclosed ingredients. ### Short answers **What is the best gnat repellent?** No agency ranks products. Illinois DPH names DEET and picaridin as the actives to look for against biting flies, and the CDC says to pick an EPA-registered repellent whose label lists flies, biting flies, or Culicoides. 111 of the 631 registered skin repellents carry a stated gnat protection time on their federal label. **Why do gnats get through my window screens?** Illinois DPH: their tiny size, no more than 1/32 of an inch, lets them penetrate window and door screens. The CDC's fix is 20x20 mesh. **Does a fan really keep gnats away?** Yes, and it is the cheapest tool on this page. The CDC recommends fans outdoors to blow biting midges away; Illinois DPH notes fans keep small areas free of smaller flies because their flight is affected by air currents. **Do gnats bite during the day?** Biting midges will bite during the day or at night, per Illinois DPH, and they are at their worst along shorelines. Timing your porch hours around them is harder than it is for dusk-biting mosquitoes, which is why the fan and the screens do so much of the work. **Are gnats and no-see-ums the same thing?** Often, yes. Illinois DPH lists punkies, no-see-ums and gnats as names for the same biting midges. The exception is "buffalo gnats," which are black flies, a different insect with different habits. Same insect, deeper dives: [the no-see-um guide](https://longsleeve.com/blog/no-see-ums), [treating the bites](https://longsleeve.com/blog/no-see-um-bites), and [the buffalo gnat playbook](https://longsleeve.com/blog/black-fly-repellent). ### Related reading - [No-See-Ums](https://longsleeve.com/blog/no-see-ums). What they are and what repels them. - [No-See-Um Repellent](https://longsleeve.com/blog/no-see-um-repellent). Check the label for biting midges. - [Black Fly Repellent](https://longsleeve.com/blog/black-fly-repellent). DEET, picaridin, clothing, and timing. - [Sand Flea Bites](https://longsleeve.com/blog/sand-flea-bites). Midges, sand flies, true fleas, and treatment. More Longsleeve in your Google feed: ### Sources 1. Illinois Department of Public Health, Biting Flies. [https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html](https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html) 1. CDC, Preventing Oropouche. [https://www.cdc.gov/oropouche/prevention/index.html](https://www.cdc.gov/oropouche/prevention/index.html) 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) Last reviewed 2026-08-26 · every claim on this page is sourced above ## How Long Does Picaridin Last? 3 to 14 Hours, Per EPA Labels URL: https://longsleeve.com/blog/how-long-does-picaridin-last > Picaridin lasts 3 to 4 hours at 5% and up to 14 hours as a 20% lotion, per EPA labels; sprays 12, wipes 8. What shortens it, when to reapply, and how to store it. Source: https://longsleeve.com/blog/how-long-does-picaridin-last By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 16, 2026 · Updated September 9, 2026 **Short answer:** Picaridin duration depends on the product label. EPA-listed examples range from 3 to 4 hours for a 5 percent formula to 14 hours for some 20 percent lotions and creams, with other 20 percent sprays and wipes listed for shorter times. Sweat, water, temperature, activity, and individual mosquito or tick attraction can change real-world performance, so follow the label for reapplication. Picaridin is a synthetic repellent first made in the 1980s, designed to resemble piperine, a natural compound found in the group of plants used to produce black pepper. It was widely used in Europe and Australia before becoming available in the United States in 2005, and it works by making insects less likely to bite, apparently by blocking mosquitoes from sensing their prey. It does not kill them. EPA lists picaridin as the active ingredient in about 40 registered skin-applied repellent products, and how long each one lasts is written on its label, not baked into the ingredient itself. ### How does the EPA approve protection times for repellents? When a skin-applied repellent is EPA registered, that means the product was evaluated and approved for both human safety and effectiveness when used according to the label. The registration number on the back is shorthand for a data submission: the company provided EPA with technical information on the product's safety and its effectiveness against mosquitoes and/or ticks. Protection times work the same way. The times shown in EPA's repellent search tool have been approved for product labels, and they are based on the effectiveness data each company submitted. Even with scientific testing guidelines and approved study methods, the resulting protection times can vary between products because testing conditions differ. That is why EPA says some repellents work longer than others, and advises choosing a product with a protection time that matches your expected activity. Two more markers are worth knowing. Some products carry EPA's repellency awareness graphic, which identifies the pest a product is expected to repel and how long the repellent is expected to be effective. The numbers in that graphic represent typical protection times based on multiple reliable studies, and products with the graphic have gone through an extra EPA review. At the other end of the spectrum, repellents made from EPA-exempt minimum-risk ingredients, have not been evaluated by EPA for effectiveness at all. We unpack how repellent testing works on our [science page](https://longsleeve.com/science). ### How long does picaridin last by formulation? [Picaridin products come as pump sprays, liquids, aerosols, and wipes](https://longsleeve.com/blog/picaridin-lotion-vs-spray), and they can be used on human skin or clothing to repel mosquitoes, biting flies, ticks, fleas, and chiggers. EPA's search tool lets you filter these products by pest, protection time, active ingredient, and other product details. Here is what the tool lists for a representative product in each form: | Product (EPA Reg. No.) | Form | Picaridin | Mosquitoes | Ticks | |---|---|---|---|---| | Sawyer Picaridin Insect Repellent Lotion (39967-50-58188) | Lotion | 20% | 14 hours | 14 hours | | KBR 3023 All Family Insect Repellent Cream (39967-50) | Cream | 20% | 14 hours | 14 hours | | Ranger Ready Repellents Tick + Insect Spray (93221-1) | Spray | 20% | 12 hours | 12 hours | | Natrapel 8 Hour Insect Repellent Wipes (56575-14) | Wipes | 20% | 8 hours | 8 hours | | OFF! FamilyCare Insect Repellent II (4822-536) | Not specified in the entry | 5% | 3 to 4 hours | X | Two notes travel with this table. First, an X in a protection time column means the product has not been registered for protection from ticks. Second, EPA states the information in this database was last updated in June 2019, so treat these numbers as approved label listings and check the label on the bottle you actually buy. Notice the spread. Four of those five rows use the same 20 percent concentration, and the listed times still run from 8 to 14 hours. None of those numbers is wrong. Each is the protection time approved for that specific product's label, and approved times can vary between products because testing conditions differ. For comparison, studies in EPA's database indicate DEET repels ticks for about two to ten hours and mosquitoes from two to twelve hours, depending on the percentage of DEET in the product. We put the two ingredients side by side in [picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet). ### What shortens picaridin protection in the real world? Label times come from controlled testing, and real days outdoors are messier. Per EPA, a repellent's effectiveness can vary due to conditions like physical activity and perspiration, water exposure, air temperature, and how attractive you personally are to mosquitoes and ticks. Every person is different on that last one. The other variable is you. [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) warns that if you do not follow the label directions, the product may not be as effective as you expect. That includes the amount: EPA's guidance is not to overuse a repellent, but to be sure you apply the amount the label indicates. ### When should you reapply picaridin? On the schedule printed on your product's label. EPA's guidance is to apply and reapply a repellent according to the label instructions, and the CDC says the same: always follow the product label and reapply as directed. The interval is product-specific because approved protection times are product-specific. A few placement rules come from the same sources. Apply repellent only to exposed skin and/or clothing, never under clothing. If you are using sunscreen, the CDC says to apply [sunscreen first and insect repellent second](https://longsleeve.com/blog/bug-spray-and-sunscreen). And when you head back indoors, EPA advises washing treated skin and clothes with soap and water. The reason to stay on schedule is simple: per [NPIC](https://npic.orst.edu/ingred/ptype/repel.html), insect repellents can help reduce your risk of being bitten, and with it your risk of getting a disease carried by mosquitoes or ticks. Choose a protection time that fits your whole activity, not just the first half of it. If you are shopping for children, we cover that separately in our guide to [mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). ### Does picaridin expire, and how should you store it? Here is the honest answer: none of the sources this article draws on (EPA, CDC, NPIC) states a numeric shelf life for picaridin repellents, and we will not invent one. The expiry question has its own piece now: [does picaridin expire](https://longsleeve.com/blog/does-bug-spray-expire) covers what EPA actually requires on a label, heat, freezing and disposal. What the sources do offer is storage guidance, and it applies here because insect repellents are pesticides. "Pesticide" is a broad term that includes products that do not kill anything, repellents included. NPIC's storage guidance starts with the container: keep pesticides in their original containers, which are designed to protect the product and are made of materials that withstand the chemicals inside. Then temperature: extremes can change the chemistry of some pesticides inside the container, and can damage the container itself. As a general rule, [NPIC](https://npic.orst.edu/health/storage.html) says pesticides are best stored between 40 and 90 degrees Fahrenheit, and to always read the label for storage instructions. Two more habits complete the picture. NPIC advises keeping your pesticide inventory as low as possible: buy only what you need this season rather than stockpiling. And EPA says to store insect repellents safely out of the reach of children, such as in a locked utility cabinet or garden shed. A bottle bought for this season, kept in its original container away from temperature extremes, and used according to its label is the storage picture every one of these sources points to. A note on ours: Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance free, with nine disclosed ingredients, and the full details are on the [product page](https://longsleeve.com/product). ### Frequently asked questions **Does picaridin last longer than DEET?** Both depend on the specific product. Studies in EPA's database indicate DEET repels ticks for about two to ten hours and mosquitoes from two to twelve hours, depending on the percentage of DEET in the product. Picaridin products in EPA's search tool list approved times such as 3 to 4 hours up to 14 hours, depending on the product. Compare labels, not just ingredients. **How long does picaridin stay in your body?** Not long. In humans, less than 6 percent of picaridin applied to skin was absorbed, and almost all of it is excreted in urine within a day of exposure, per NPIC. **Is picaridin recommended for ticks?** The CDC recommends using EPA-registered insect repellents containing DEET, picaridin, IR3535, Oil of Lemon Eucalyptus, para-menthane-diol, or 2-undecanone for tick protection. Still, check your specific product: in EPA's search tool, an X in the tick column means that product has not been registered for protection from ticks. **Can you use picaridin while pregnant or breastfeeding?** The CDC points people to EPA-registered insect repellents used as directed, including for pregnant and breastfeeding women, and its list includes picaridin, known as KBR 3023 and icaridin outside the United States. If you have specific health questions, talk to your clinician. ### Related reading - [Picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet). Duration, kids, ticks, and materials. - [Picaridin Lotion vs Spray](https://longsleeve.com/blog/picaridin-lotion-vs-spray). How the two forms compare. - [Does Bug Spray Expire?](https://longsleeve.com/blog/does-bug-spray-expire) What EPA's label rules require. - [Should You Wash Off Bug Spray?](https://longsleeve.com/blog/wash-off-bug-spray) What the label says about bedtime and after a hike. More Longsleeve in your Google feed: ### Sources 1. EPA, Regulation of Skin-Applied Repellents: [https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents](https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents) 1. EPA, Find the Repellent that is Right for You: [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. EPA, Repellent Search Tool Results: [https://cfpub.epa.gov/oppref/insect_s/search_results.cfm](https://cfpub.epa.gov/oppref/insect_s/search_results.cfm) 1. EPA, Repellency Awareness Graphic: [https://www.epa.gov/insect-repellents/repellency-awareness-graphic](https://www.epa.gov/insect-repellents/repellency-awareness-graphic) 1. EPA, DEET: [https://www.epa.gov/insect-repellents/deet](https://www.epa.gov/insect-repellents/deet) 1. EPA, Skin-Applied Repellent Ingredients: [https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients) 1. EPA, Using Insect Repellents Safely and Effectively: [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. EPA, What is an Insect Repellent?: [https://www.epa.gov/insect-repellents/what-insect-repellent](https://www.epa.gov/insect-repellents/what-insect-repellent) 1. CDC, Preventing Mosquito Bites: [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC, Preventing Tick Bites: [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. NPIC, Picaridin General Fact Sheet: [https://npic.orst.edu/factsheets/PicaridinGen.html](https://npic.orst.edu/factsheets/PicaridinGen.html) 1. NPIC, Pesticide Storage: [https://npic.orst.edu/health/storage.html](https://npic.orst.edu/health/storage.html) 1. NPIC, Insect Repellents: [https://npic.orst.edu/ingred/ptype/repel.html](https://npic.orst.edu/ingred/ptype/repel.html) Last reviewed 2026-08-16 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Natrapel 8 Hour Insect Repellent Continuous Spray](https://longsleeve.com/repellent-index/natrapel-8-hour-insect-repellent-continuous-spray) ## How to Keep Mosquitoes Away From Your Patio URL: https://longsleeve.com/blog/how-to-keep-mosquitoes-away-from-patio-dinner > Dump standing water weekly, use an EPA-registered repellent on exposed skin, run a fan. What the CDC, EPA and field studies say about candles and sprays. Source: https://longsleeve.com/blog/how-to-keep-mosquitoes-away-from-patio-dinner By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 31, 2026 · Updated October 2, 2026 **Short answer:** Start with water: the CDC says to empty and scrub, turn over, cover, or throw out anything that holds water once a week. The CDC also says to use an EPA-registered insect repellent, and University of Maryland Extension says to use fans when sitting outside on a porch, deck, or patio. Citronella candles and butane-powered repellers, the extension says, do not protect areas their smoke or vapor does not reach. ### What do the CDC and EPA say to do first? Get rid of standing water. The [CDC](https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-at-home.html)'s advice for controlling mosquitoes outside your home is to remove standing water where they lay eggs: once a week, empty and scrub, turn over, cover, or throw out any items that hold water, like tires, buckets, planters, toys, pools, birdbaths, flowerpot saucers, or trash containers. It also says to tightly cover water storage containers such as buckets, cisterns and rain barrels. EPA's list adds fountains, wading pools and potted plant trays, emptied and changed at least once a week, and EPA names removing mosquito habitats first among its four tactics for mosquito control. Small amounts of water count, and the cycle is fast. [University of Maryland Extension](https://extension.umd.edu/resource/controlling-mosquitoes) says mosquitoes can breed in as little as one teaspoon of water, and that it can take as little as four days for them to go from eggs to adults. The mosquitoes may also be local: the CDC says Aedes aegypti and Aedes albopictus do not fly long distances, and will only fly a few blocks in their lifetime. Water work has a limit. [EPA](https://www.epa.gov/mosquitocontrol/success-mosquito-control-integrated-approach) says egg and larva interventions are generally the most effective, least costly way to control mosquitoes, but are unlikely to be 100% effective. University of Maryland Extension pairs two steps: wearing repellents and eliminating standing water are, it says, two of the most effective things you can do to protect yourself from mosquito bites. The full weekly routine is in our [standing water checklist](https://longsleeve.com/blog/standing-water-mosquito-control). Two details for the porch itself. The CDC says to install or repair and use window and door screens, and not to leave doors propped open. [EPA](https://www.epa.gov/insect-repellents/tips-prevent-mosquito-bites) suggests replacing outdoor lights with yellow "bug" lights, which tend to attract fewer mosquitoes than ordinary lights, and adds that the yellow lights are not repellents. ### What should guests put on their skin, and what should they wear? An EPA-registered repellent on exposed skin. The CDC says to use EPA-registered insect repellents, and lists these active ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, and 2-undecanone. It says to look for an EPA registration number on the product label, which means the company provided EPA with technical information on the effectiveness of the product. [EPA](https://www.epa.gov/insect-repellents/find-repellent-right-you)'s advice is to use a product with a protection time that fits your activity, and you can compare registered products' label times in [The Repellent Index](https://longsleeve.com/repellent-index). The [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html)'s rules for using it are short: always follow the product label instructions, reapply repellent as directed, do not apply repellent on the skin under clothing, and if you are using sunscreen, apply sunscreen first and insect repellent second. It also says not to use products containing oil of lemon eucalyptus or PMD on children under 3 years old. Conditions matter too: the CDC Yellow Book says duration of protection is markedly affected by ambient temperature, level of activity, amount of perspiration, exposure to water and being rubbed off. Clothing does the rest. The CDC recommends loose-fitting, long-sleeved shirts and pants, and clothing and gear treated with permethrin, with one firm rule: do not use permethrin products directly on skin. EPA adds socks, and tucking pants into socks to cover gaps in your clothing where mosquitoes can get to your skin. Our guide to [permethrin-treated clothing](https://longsleeve.com/blog/permethrin-clothing) covers how long a treatment lasts. ### Do fans keep mosquitoes away? One field study points that way. In a Central Michigan wetland, Hoffmann and Miller reported in 2003 that electric fan-generated wind strongly reduced mosquito catches in carbon dioxide baited traps, over wind speeds from 0 to 3.7 meters per second, or 0 to 8.3 miles per hour. That study counted mosquitoes caught in traps, not bites on people. How it works is the interesting part. The authors concluded that applied wind diminishes mosquito catches primarily by diluting attractants rather than by exceeding mosquito flight capability. [NPIC](https://npic.orst.edu/factsheets/repellents.html) says mosquitoes are attracted to skin odors and the carbon dioxide we exhale, and the American Mosquito Control Association says carbon dioxide draws mosquitoes from up to 35 meters. Our post on [why mosquitoes bite some people more](https://longsleeve.com/blog/why-mosquitoes-bite-some-people) covers those attractants. The authors recommended that fan-generated wind be pursued as a practical means of protecting humans or pets from mosquitoes in the backyard setting. One number needs its context. In a 2002 test, the same researchers used an electric fan to draw air through a DEET-impregnated screen and project it toward a person, which reduced mosquito landing by 75% relative to no applied wind or DEET. That result is a fan combined with DEET, not a fan alone. For the patio itself, University of Maryland Extension says to use fans to keep the air circulating when sitting outside on a porch, deck, or patio, and the American Mosquito Control Association calls a large fan on your deck a low-tech solution. ### Do citronella candles and mosquito coils work outdoors? A little, and only close by. University of Maryland Extension says citronella candles, mosquito lamps and butane-powered repellers have limited effectiveness: the repellent is found in their smoke or vapor, so areas where the smoke or vapor does not reach are not protected. The studies put numbers on that. In a field trial published in 1996, Lindsay and colleagues reported that subjects received on average 6.2 bites per 5 minutes at positions with citronella candles, 8.2 with plain candles and 10.8 with no candles, and described the overall reduction in bites from the citronella candles as only 42.3%. The [American Mosquito Control Association](https://www.mosquito.org/faqs/) says citronella candles have a mild repellent effect, but do not offer significantly more protection than other candles producing smoke. A 2008 study by Muller and colleagues found citronella candles reduced the number of female mosquitoes caught in traps by 35.4% at a distance of 1 meter, and that the repellency dropped significantly at 2 and 3 meters. In a 2017 study by Rodriguez and colleagues, of the five wearable devices tested, only the one that releases metofluthrin significantly reduced the numbers of attracted mosquitoes, and the citronella candle had no effect. Coils belong to a different category. The [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) Yellow Book says spatial repellents, including mosquito coils, contain active ingredients such as metofluthrin and allethrin, and that coils and spatial repellents repel mosquitoes from more circumscribed areas. It also says that many of these products have not yet been adequately evaluated in peer-reviewed studies for efficacy in preventing vector-borne diseases. The American Mosquito Control Association says mosquito coils and heated repellent devices can provide some protection, but are most effective in situations of little wind. Fans work by moving air, and the association says these devices work best in little wind. The Yellow Book gives two instructions for spatial repellents: supplement them with an EPA-registered repellent on skin or clothing, and avoid direct inhalation of spray or smoke. Our guide to [mosquito repellent candles](https://longsleeve.com/blog/mosquito-repellent-candles) goes through what is in them and how to read the label. ### Should you spray the yard before a party? The sources differ. The CDC says you can use an outdoor adulticide to kill adult mosquitoes in areas where they rest, such as under patio furniture, and to always follow label instructions. [Penn State Extension](https://extension.psu.edu/got-mosquitoes-eliminate-mosquitoes-with-ipm) says residential spraying or fogging outdoors is the least effective method for killing mosquitoes and is not recommended. If you do spray, the CDC is specific about where and how. It says mosquitoes rest under plants, in dense brush or tall grasses, on the undersides of leaves on trees and bushes, under the eaves on buildings, under decks and porches, and in moist, shady areas. It lists coils, foggers, yard sprays or aerosols, and liquids as the forms adulticides come in. Its label rules: do not apply more product than recommended or reapply more often than the label states, and do not apply to fruits and vegetables in your garden, to plants in bloom, or to plants that bees, butterflies, and other pollinators visit. For a party, the timing rule is the [CDC](https://www.cdc.gov/mosquitoes/mosquito-control/adulticides.html)'s: keep people and pets out of the area you treat until the product has dried, usually about an hour. Expect limits as well. University of Maryland Extension says area-wide sprays or foggers are only effective temporarily, lasting 1 to 3 weeks depending on the chemical and the weather conditions, and that they do not protect you from new adult mosquitoes flying in from surrounding areas. Penn State Extension says eliminating or treating standing water around your home is easier and more effective than spraying pesticides for adult mosquitoes. For pesticide questions, the CDC points to the National Pesticide Information Center, at 1-800-858-7378. ### Do bug zappers, ultrasonic devices or mosquito plants help? The evidence gathered here does not support any of the three. On zappers, the American Mosquito Control Association reports that in the only two controlled studies by independent investigators, at the University of Notre Dame, mosquitoes made up 4.1% and 6.4% of the daily catch over a season, and that neither study found a significant difference in the number of mosquitoes in yards with or without bug zappers. Penn State Extension says to avoid bug zappers, because research has shown that they kill few mosquitoes. More in [do bug zappers work](https://longsleeve.com/blog/bug-zappers). On ultrasonic devices, the CDC Yellow Book says wearing sound-emitting devices is ineffective. A 2007 Cochrane review of electronic mosquito repellents by Enayati, Hemingway and Garner found that all ten field studies it included showed no difference in the number of mosquitoes caught from the bare body parts of participants with or without one. [EPA](https://www.epa.gov/pesticides/pesticide-devices-guide-consumers) classes ultrasonic repellers and hand-held bug zappers as devices, and says device manufacturers generally do not submit their claims or efficacy and safety data to EPA before selling. Details in [do ultrasonic mosquito repellers work](https://longsleeve.com/blog/ultrasonic-repellers). On plants, University of Maryland Extension says there are no plants that have been scientifically found to keep mosquitoes away. The citrosa plant has been claimed to repel mosquitoes within a 10 square foot area; in a paper published in 1996, Matsuda and colleagues found no significant difference between citrosa-treated and nontreated subjects, and in a paper published in 1994, Cilek and Schreiber observed no significant differences in the number of mosquitoes landing on people's forearms where plants were present compared with areas without plants. The CDC says we do not know the effectiveness of non-EPA-registered insect repellents, including some natural repellents, and [EPA](https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents) says unregistered repellents, made from ingredients such as citronella oil, cedar oil, geranium oil and peppermint oil, have not been evaluated for effectiveness. Oil of citronella and catnip oil do appear on EPA's list of skin-applied repellent ingredients, with a few registered products each. The evidence on the oils is in [do citronella candles work](https://longsleeve.com/blog/citronella-and-plant-repellents). ### About Longsleeve Longsleeve is an EPA-registered insect repellent lotion with 20% picaridin (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours, is fragrance free, and goes on exposed skin as the label directs. ### Common questions **What smells do mosquitoes hate?** The agency sources gathered here do not list smells that keep mosquitoes away. The CDC says we do not know the effectiveness of non-EPA-registered insect repellents, including some natural repellents, and EPA says unregistered repellents, made from ingredients such as citronella oil, cedar oil, geranium oil and peppermint oil, have not been evaluated for effectiveness. What mosquitoes are attracted to, NPIC says, is skin odors and the carbon dioxide we exhale. **What can I put on my deck to keep mosquitoes away?** A fan. University of Maryland Extension says to use fans to keep the air circulating when sitting outside on a porch, deck, or patio, and the American Mosquito Control Association calls a large fan on your deck a low-tech solution. EPA says yellow bug lights tend to attract fewer mosquitoes than ordinary lights but are not repellents, and the extension says citronella candles, mosquito lamps and butane-powered repellers do not protect areas their smoke or vapor does not reach. **When are mosquitoes worst on a patio?** It depends on the species. The CDC Yellow Book says mosquitoes bite throughout the day and night, that peak biting for Aedes aegypti is after sunrise and at sunset, and that peak biting for Culex quinquefasciatus, a vector for West Nile encephalitis, is typically after sunset, usually between 10 and 11 p.m. The American Mosquito Control Association suggests scheduling activities to avoid the times mosquitoes are most active, usually dawn and dusk. **What repellent should I set out for guests?** One that is EPA-registered, with an active ingredient the CDC lists: DEET, picaridin, IR3535, oil of lemon eucalyptus, PMD or 2-undecanone. The CDC says to look for the EPA registration number on the label, and EPA says to use a product with a protection time that fits your activity. **How long before guests arrive should I spray the yard?** The CDC says to keep people and pets out of the area you treat until the product has dried, usually about an hour, and to follow label instructions, including not applying more product than recommended. Penn State Extension does not recommend residential spraying or fogging, and says eliminating or treating standing water is easier and more effective. **What is a mosquito's worst enemy?** Predators help only a little, on the evidence here. University of Maryland Extension says fish, spiders, beneficial insects, bats, and birds all feed on mosquitoes and provide some natural control. The American Mosquito Control Association reports that mosquitoes have made up less than 1% of the gut contents of wild caught bats, and no more than 0 to 3 percent of the diet of martins. ### Related reading - [Standing Water and Mosquitoes](https://longsleeve.com/blog/standing-water-mosquito-control). The weekly yard checklist. - [Mosquito Repellent Candles, Torches and Coils](https://longsleeve.com/blog/mosquito-repellent-candles). What works and what the label says. - [Do Bug Zappers Work on Mosquitoes?](https://longsleeve.com/blog/bug-zappers) What field studies found. - [Permethrin-Treated Clothing](https://longsleeve.com/blog/permethrin-clothing). How often to re-treat and how long it lasts. - [Why Mosquitoes Bite Some People More](https://longsleeve.com/blog/why-mosquitoes-bite-some-people). CO2, odor, heat, and color. ### Sources 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. EPA, Skin-Applied Repellent Ingredients. [https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients) 1. NPIC, Insect Repellents Fact Sheet. [https://npic.orst.edu/factsheets/repellents.html](https://npic.orst.edu/factsheets/repellents.html) 1. CDC, Mosquito Control at Home, April 16, 2024. [https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-at-home.html](https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-at-home.html) 1. U.S. EPA, Tips to Prevent Mosquito Bites. [https://www.epa.gov/insect-repellents/tips-prevent-mosquito-bites](https://www.epa.gov/insect-repellents/tips-prevent-mosquito-bites) 1. U.S. EPA, Success in Mosquito Control: An Integrated Approach. [https://www.epa.gov/mosquitocontrol/success-mosquito-control-integrated-approach](https://www.epa.gov/mosquitocontrol/success-mosquito-control-integrated-approach) 1. University of Maryland Extension, Controlling Mosquitoes, updated April 16, 2026. [https://extension.umd.edu/resource/controlling-mosquitoes](https://extension.umd.edu/resource/controlling-mosquitoes) 1. CDC, Life Cycle of Aedes Mosquitoes. [https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html](https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. Hoffmann and Miller, J Med Entomol 2003;40(5):607-14 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/14596273/](https://pubmed.ncbi.nlm.nih.gov/14596273/) 1. American Mosquito Control Association, FAQs. [https://www.mosquito.org/faqs/](https://www.mosquito.org/faqs/) 1. Hoffmann and Miller, J Med Entomol 2002;39(6):935-8 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/12495196/](https://pubmed.ncbi.nlm.nih.gov/12495196/) 1. Lindsay et al., J Am Mosq Control Assoc 1996;12(2 Pt 1):293-4 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/8827606/](https://pubmed.ncbi.nlm.nih.gov/8827606/) 1. Muller et al., J Am Mosq Control Assoc 2008;24(1):154-60 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/18437832/](https://pubmed.ncbi.nlm.nih.gov/18437832/) 1. Rodriguez et al., J Insect Sci 2017;17(1):24 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/28423421/](https://pubmed.ncbi.nlm.nih.gov/28423421/) 1. Penn State Extension, Got Mosquitoes? Eliminate Mosquitoes with IPM. [https://extension.psu.edu/got-mosquitoes-eliminate-mosquitoes-with-ipm](https://extension.psu.edu/got-mosquitoes-eliminate-mosquitoes-with-ipm) 1. CDC, Adulticides, June 25, 2026. [https://www.cdc.gov/mosquitoes/mosquito-control/adulticides.html](https://www.cdc.gov/mosquitoes/mosquito-control/adulticides.html) 1. Enayati, Hemingway and Garner, Cochrane Database of Systematic Reviews 2007, Electronic mosquito repellents for preventing mosquito bites and malaria infection (Cochrane summary page). [https://www.cochrane.org/evidence/CD005434_electronic-mosquito-repellents-preventing-mosquito-bites-and-malaria-infection](https://www.cochrane.org/evidence/CD005434_electronic-mosquito-repellents-preventing-mosquito-bites-and-malaria-infection) 1. U.S. EPA, Pesticide Devices: A Guide for Consumers. [https://www.epa.gov/pesticides/pesticide-devices-guide-consumers](https://www.epa.gov/pesticides/pesticide-devices-guide-consumers) 1. Matsuda et al., J Am Mosq Control Assoc 1996;12(1):69-74 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/8723261/](https://pubmed.ncbi.nlm.nih.gov/8723261/) 1. Cilek and Schreiber, J Am Mosq Control Assoc 1994;10(4):473-6 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/7707049/](https://pubmed.ncbi.nlm.nih.gov/7707049/) 1. U.S. EPA, Regulation of Skin-Applied Repellents. [https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents](https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents) Last reviewed 2026-10-02 · every claim on this page is sourced above ## Insect Repellent for Hiking: Ticks, Mosquitoes, and Permethrin URL: https://longsleeve.com/blog/insect-repellent-for-hiking > A hiking bite-protection checklist using CDC, EPA, and NPIC guidance: permethrin-treated gear, EPA-registered skin repellent, trail habits, reapplication, and post-hike checks. Source: https://longsleeve.com/blog/insect-repellent-for-hiking By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 17, 2026 · Updated September 9, 2026 **Short answer:** For hiking, CDC-style protection is layered. Treat boots, socks, pants, and gear with 0.5 percent permethrin before the trip, then use an EPA-registered skin repellent on exposed skin at the trailhead. Walk the center of the trail, reapply according to the repellent label, shower after coming indoors, and check your body, clothing, gear, and pets for ticks. ### Why do hikers need a bite plan at all? The CDC's Yellow Book names hiking and camping among the activities that bring people into close contact with ticks. That tracks: ticks live in grassy, brushy, or wooded areas, which describes most trail corridors, and they can be found in every U.S. state, though not all ticks spread the same germs. The stakes are not abstract. Nearly half a million people are diagnosed and treated for a tickborne disease in the United States each year, and a 2021 CDC estimate based on insurance records puts Lyme disease alone at approximately 476,000 Americans annually. Reported cases of Lyme disease, anaplasmosis, babesiosis, and Powassan virus disease are concentrated in the Northeast, mid-Atlantic, and upper Midwest, with pockets of risk along the Pacific coast. Exposure can happen year-round, but ticks are most active in the warmer months, April through September. Mosquitoes earn a spot in the plan too. They bite day and night and can spread germs that make you sick. West Nile virus is the leading cause of mosquito-borne disease in the contiguous United States; per the [CDC](https://www.cdc.gov/west-nile-virus/about/index.html), each year more than 1,300 people develop severe illness affecting the central nervous system and more than 130 die. None of this needs to keep you home; it changes what you do the night before, at the trailhead, on the trail, and when you get back. Here is the whole day, in order. ### What should you treat before you leave for the trailhead? Gear comes first, and it starts at home. The CDC advises treating clothing and gear with products containing 0.5% permethrin, and it lists boots, pants, socks, and tents among the items that can be treated. You can also buy clothing and gear pre-treated. At that 0.5% concentration, permethrin-treated clothing repels and kills [chiggers](https://longsleeve.com/blog/chigger-bites), mosquitoes, ticks, and other biting arthropods. Permethrin itself is an insecticide in the pyrethroid family, synthetic chemicals that act like natural extracts from the chrysanthemum flower. Two rules govern the job. First, timing: treat clothing and gear 24 to 48 hours before you pack so everything has time to dry, and always follow the label instructions. Second, placement: permethrin should never be applied to skin, only to clothing, mosquito nets, or other fabrics as directed on the product label. Your skin gets a different product. The treatment lasts. Permethrin-treated clothing remains protective through several washings, and treated materials keep their repellent and insecticidal activity through repeated launderings, though they need retreatment as described on the product label. The label also tells you to wash treated clothing separately from untreated clothing, and treated products are not to be applied to certain clothing such as underwear. We walk through the full gear-plus-skin routine in our [permethrin and picaridin system guide](https://longsleeve.com/blog/permethrin-picaridin-system). ### What goes on your skin at the trailhead? Exposed skin gets an EPA-registered repellent. The CDC recommends EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone, and says to check for an EPA registration number on the label. That number means the company provided EPA with technical information on the product's effectiveness. Picaridin is the active we know best. It is a synthetic compound first made in the 1980s, modeled on piperine, a natural compound found in the plants used to produce black pepper. It works by repelling rather than killing; it appears to block mosquitoes from sensing their prey. It can be used on skin or clothing to repel mosquitoes, biting flies, ticks, fleas, and chiggers. For how protection windows play out in practice, see [how long picaridin lasts](https://longsleeve.com/blog/how-long-does-picaridin-last). Application is simpler than most people make it. A thin, even film over exposed skin is enough; heavy application and saturation are generally unnecessary for effectiveness. Exposed is the operative word: do not apply repellent on skin under clothing. And the [EPA](https://www.epa.gov/insect-repellents/repellent-treated-clothing) makes a point every hiker should memorize: permethrin-treated clothing protects only the skin it covers, so treat the rest of your exposed skin with a repellent labeled for use on human skin. That is the whole logic of the two-layer approach. If the sun is out, order matters. The CDC says apply [sunscreen first and insect repellent second](https://longsleeve.com/blog/bug-spray-and-sunscreen). The Yellow Book adds that you should use separate products rather than a combination sunscreen-repellent, because sunscreen may need to be reapplied more often and in larger amounts than the repellent component. Clothing does quiet work too. The CDC advises loose-fitting, long-sleeved shirts and pants for mosquitoes, and the Yellow Book recommends minimizing exposed skin with long sleeves, long pants, boots, and hats, tucking in your shirt, tucking pants into socks, and wearing closed shoes instead of sandals. Pants tucked into socks look ridiculous and reduce risk anyway. One packing note, courtesy of the National Pesticide Information Center: DEET acts as a plasticizer and can damage certain rubber, plastic, vinyl, or elastic materials, including eyeglass frames and lenses, watch crystals, and certain synthetic fabrics. It does not damage natural fibers like cotton and wool. Whichever active you carry, check the product label for handling directions. ### How do ticks actually get on you mid-hike? Not the way most people picture. Ticks cannot fly or jump. They find hosts by detecting breath and body odor, or by sensing body heat, moisture, and vibrations, and many species wait for a host on the tips of grasses and shrubs in a position known as questing. Per the CDC, ticks even pick their waiting spot by identifying well-used paths. A questing tick holds onto leaves and grass with its back legs and stretches its first pair of legs out, waiting. When you brush the spot where it sits, it climbs aboard. Some attach quickly; others wander, looking for places like the ear, or other areas where the skin is thinner. This is why trail position matters. The CDC advises avoiding wooded and brushy areas with high grass and leaf litter and walking in the center of trails, and its Yellow Book repeats the advice for hikers specifically: stay in the center of hiking trails. The brushy shortcut is exactly where the waiting happens. Meanwhile, your morning application is aging. The EPA notes that a repellent's effectiveness can vary with physical activity and perspiration, water exposure, air temperature, and how attractive you personally are to mosquitoes and ticks. The CDC's Yellow Book goes further: efficacy and duration of protection vary considerably among products and are markedly affected by ambient temperature, activity level, perspiration, water exposure, and being rubbed off during activity. So apply and reapply according to the label, using the amount the label indicates. If you start getting bitten, reapply, but never more often than the label allows. ### What should you do back at camp or at home? The hike ends; the checklist does not. Per the CDC, showering within two hours of coming indoors has been shown to reduce your risk of getting Lyme disease, may help wash off unattached ticks, and is a good opportunity to do a tick check. Do the full-body check with a mirror, and be systematic about it: under the arms, in and around the ears, inside the belly button, behind the knees, in and around the hair, between the legs, and around the waist. If you find something and are not sure what it is, our [tick identification guide](https://longsleeve.com/blog/tick-identification) can help. If one has attached, our [tick removal guide](https://longsleeve.com/blog/tick-removal) walks through the steps. Clothes go straight into the dryer: tumble drying on high heat for 10 minutes kills any ticks on dry clothing, and damp clothes may need more time. Then check the rest of the kit. Ticks can ride into your home on clothing, pets, and daypacks and attach to a person later, so examine pets, coats, and packs carefully. If a tick has attached, or you develop symptoms after a trip, talk to a clinician. ### What does not work? The trail community has its folk remedies, and the CDC's Yellow Book is blunt about them: eating vitamin B or garlic and wearing sound-emitting devices or repellent-impregnated wristbands are ineffective. More broadly, the effectiveness of non-EPA-registered repellents, including some natural repellents, is not known, which is why the [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html) and EPA recommend using an EPA-registered insect repellent. ### Where does Longsleeve fit in? Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. Its approved label also states that it won't damage fishing lines, plastics, or other synthetic materials. ### Frequently asked questions **Can I put permethrin on my skin?** No. The CDC's Yellow Book says permethrin should never be applied to skin, only to clothing, mosquito nets, or other fabrics as directed on the product label. It belongs on boots, pants, socks, and tents, applied 24 to 48 hours before you pack so everything can dry. **How often should I reapply repellent on a hike?** Follow the label. The EPA says to apply and reapply according to the label instructions, and the CDC advises that if you start getting bitten you should reapply, but never more often than the label allows. Perspiration, water exposure, and rub-off can all shorten protection. **Does sunscreen go on before or after insect repellent?** Sunscreen first, repellent second, per the CDC. The Yellow Book also advises using separate products rather than a combination sunscreen-repellent, because sunscreen may need to be reapplied more often and in larger amounts than the repellent component. **When is tick season for hikers?** Tick exposure can happen year-round, but ticks are most active during the warmer months, April through September. They can be found in every U.S. state, though not all ticks spread the same germs. **Do repellent wristbands or garlic work?** No. The CDC's Yellow Book lists eating vitamin B or garlic and wearing sound-emitting devices or repellent-impregnated wristbands as ineffective. The CDC and EPA recommend using an EPA-registered insect repellent instead. ### Related reading - [Permethrin and Picaridin](https://longsleeve.com/blog/permethrin-picaridin-system). The two-layer tick and mosquito system. - [Permethrin-Treated Clothing](https://longsleeve.com/blog/permethrin-clothing). How often to re-treat, how long it lasts, and why it never goes on skin. - [How to Remove a Tick](https://longsleeve.com/blog/tick-removal). Tweezers, timing, and what not to do. - [Bug Spray and Sunscreen](https://longsleeve.com/blog/bug-spray-and-sunscreen). Which goes on first and how long to wait. More Longsleeve in your Google feed: ### Sources 1. CDC, Preventing Tick Bites: [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods: [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. CDC, Tick Press Kit: [https://www.cdc.gov/ticks/communication-resources/press-kit.html](https://www.cdc.gov/ticks/communication-resources/press-kit.html) 1. CDC, About Ticks: [https://www.cdc.gov/ticks/about/index.html](https://www.cdc.gov/ticks/about/index.html) 1. CDC, Preventing Mosquito Bites: [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC, About West Nile Virus: [https://www.cdc.gov/west-nile-virus/about/index.html](https://www.cdc.gov/west-nile-virus/about/index.html) 1. EPA, Using Insect Repellents Safely and Effectively: [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. EPA, Repellent-Treated Clothing: [https://www.epa.gov/insect-repellents/repellent-treated-clothing](https://www.epa.gov/insect-repellents/repellent-treated-clothing) 1. NPIC, Picaridin General Fact Sheet: [https://npic.orst.edu/factsheets/PicaridinGen.html](https://npic.orst.edu/factsheets/PicaridinGen.html) 1. NPIC, Permethrin General Fact Sheet: [https://npic.orst.edu/factsheets/PermGen.html](https://npic.orst.edu/factsheets/PermGen.html) 1. NPIC, DEET Technical Fact Sheet: [https://npic.orst.edu/factsheets/archive/DEETtech.html](https://npic.orst.edu/factsheets/archive/DEETtech.html) Last reviewed 2026-08-17 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Permethrin Around Dogs and Cats: What the Labels Say URL: https://longsleeve.com/blog/is-permethrin-safe-around-pets > Some permethrin products are labeled for dogs. Cats are the exception: what NPIC, EPA, FDA and the labels themselves say about cats, licking and clothing. Source: https://longsleeve.com/blog/is-permethrin-safe-around-pets By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 31, 2026 · Updated September 21, 2026 **Short answer:** Some permethrin products are labeled for dogs; the label sets the limits. NPIC says cats are more sensitive to permethrin than dogs or people because their bodies take a long time to break it down. One dog label, EPA Reg. No. 11556-142, reads DO NOT USE ON CATS, MAY BE FATAL. NPIC says your veterinarian can help you choose. ### Which permethrin products are labeled for dogs? NPIC names spot-on treatments for dogs among the places permethrin turns up. Its general fact sheet, reviewed in July 2009, says permethrin is used in cattle ear tags and flea collars, or in spot-on treatments for dogs, and counts more than 1400 registered products containing permethrin. Its technical fact sheet adds that some permethrin products are labeled for use only on dogs. Past that, the label on the package is the whole answer. The EPA stamped label for K9 Advantix II Medium Dog, EPA Reg. No. 11556-142, lists permethrin among its active ingredients. It is for monthly use only on dogs and puppies 7 weeks of age and older and weighing 11 to 20 lbs, and says: "For external use on dogs only. Do not use on animals other than dogs." Those numbers belong to that one product. Permethrin turns up well beyond dog products: [NPIC](https://npic.orst.edu/factsheets/PermGen.html) says products containing it may be used on livestock and pets, in structures and buildings, and on clothing. We take up [whether mosquito repellent can go on a dog](https://longsleeve.com/blog/can-i-put-mosquito-repellent-on-my-dog) separately. EPA's advice is to always read the label first, and to keep all products out of the reach of pets and children. ### Why is permethrin toxic to cats in particular? Because it takes a cat's body a long time to break permethrin down, NPIC says, cats are more sensitive to it than dogs or people. On the reason, [NPIC](https://npic.orst.edu/factsheets/archive/Permtech.html)'s technical fact sheet says cats can be sensitive to products with high concentrations of permethrin, "possibly due to insufficient glucoronide conjugation capability." A 2007 paper in the Journal of Feline Medicine and Surgery says a feline deficiency of glucuronidase transferase "may lead to prolonged detoxification." Both sources hedge, and the hedge is theirs. The signs can come late. NPIC's technical fact sheet says cats exposed dermally to some permethrin products may experience hyperexcitability, depression, ataxia, vomiting, anorexia, tremors or convulsions, and that symptoms can begin within a few minutes or up to three days after the exposure. The 2007 paper says signs usually present within 3 hours of exposure but can be delayed until 72 hours. The 2007 paper calls permethrin-based spot-on preparations contraindicated in cats because of the high risk of toxicosis. It reviewed 286 cases of inappropriate feline exposure to those preparations reported to the Veterinary Poisons Information Service (VPIS), London: 96.9 percent were symptomatic, and death occurred in 10.5 percent of cases. ### What do dog spot-on labels say about cats? They say it in capitals. The label for K9 Advantix II Medium Dog, EPA Reg. No. 11556-142, which lists permethrin among its active ingredients, prints DO NOT USE ON CATS, MAY BE FATAL, then: "Keep cats away from treated dogs for 24 hours. If applied to a cat or ingested by a cat, contact your veterinarian immediately." That wording, and that 24 hours, belong to that label. EPA has looked at how well such warnings work. [EPA](https://www.epa.gov/pets/epa-evaluation-pet-spot-products-analysis-and-plans-reducing-harmful-effects)'s evaluation of pet spot-on products found that label warnings against use of dog products on other animals, especially cats, "are not working well enough." The rule fits on one line. [NPIC](https://npic.orst.edu/health/pets2.html): "Dog products should never be used on cats." FDA: "If the product is for use on dogs, don't use it on cats." EPA says never to apply dog products to cats. The American Veterinary Medical Association says to be especially careful using insect control products for or around cats, and never to use a product that is not approved for cats "because the results could be deadly." ### What happens if a dog licks permethrin? Drooling and lip-smacking are the signs NPIC describes. Its general fact sheet says animals that have licked treated skin may drool a lot or smack their lips. Its technical fact sheet says this is believed to be a result of licking at the application site, thought to be caused either by the taste or a tingling sensation in the mouth. The K9 Advantix II Medium Dog label tells owners not to let it happen: "Do not get this product in your dog's eyes or allow your dog to ingest this product." It lists skin irritation such as redness and scratching among possible side effects, says vomiting or diarrhea have also been reported, and says to consult your veterinarian if these occur. NPIC says dermal exposures to cats and dogs may cause temporary paresthesia and neurological signs. Its general fact sheet also reports a feeding study: dogs fed permethrin for up to 2 years had more tremors than dogs that did not eat it. Each licking description above is about product applied to an animal's skin. ### What about a cat that lives with a treated dog? A cat does not have to be treated to be exposed. The 2007 Journal of Feline Medicine and Surgery paper says cats are also at risk from secondary exposure through contact with other pets treated with a permethrin spot-on. [EPA](https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/red_PC-109701_1-Apr-06.pdf)'s 2006 reregistration decision says there have been severe adverse reactions, including deaths, in cats exposed directly to concentrated permethrin products or secondarily exposed to treated dogs. NPIC's technical fact sheet describes one case: a cat was in proximity of two large dogs treated with a permethrin product 48 hours after treatment, and between 18 and 24 hours after being near the dogs it developed signs including agitation, tremors, seizures and ataxia. International Cat Care says permethrin can transfer to a cat's coat when the cat rubs against a recently treated dog, or even sits on the same furniture. The household rules we found are about product on an animal. [FDA](https://www.fda.gov/consumers/consumer-updates/safe-use-flea-and-tick-products-pets) says that if you use spray or spot-on products on multiple pets, apply to one pet at a time and keep the treated animal separated from the others until the product dries, to prevent one animal from grooming another. It calls that especially important if the product is only for use in dogs and you have a cat. NPIC says many products require treated animals to be separated after treatment to prevent touching and licking. ### What does a permethrin clothing label say about pets? Very little. The EPA stamped label we read, Traveler's Supply Inc. Permethrin Clothing and Gear Insect Repellent, EPA Reg. No. 81402-1, prints DO NOT APPLY TO SKIN and says: "Do not apply this product in a way that will contact children, either directly or through drift. Except when applying to clothing, do not allow adults or pets to enter until sprays have dried." Clothing application is the stated exception, so the label gives no rule about pets and treated clothes. Its clothing directions are addressed to the wearer: never apply it to clothing while it is being worn, and hang treated clothing to dry for at least 2 hours, 4 hours under humid conditions, before wearing. Its storage line names pets: "Store in a cool dry area away from children and pets." We found no mention of cats or dogs on it. On clothing treatments, NPIC says they "are only intended for use on fabrics," and [CDC](https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html) says: "Do not use permethrin products directly on skin." More in [treating clothing with permethrin](https://longsleeve.com/blog/permethrin-clothing) and [pairing it with a skin-applied repellent](https://longsleeve.com/blog/permethrin-picaridin-system). On cats, we found one statement. International Cat Care says permethrin is also sometimes infused in clothing to repel ticks, mosquitoes and flies, and that "there's no evidence to show that cats have been poisoned through exposure to these items of clothing." It recommends contacting the manufacturer if there is any concern. We leave that as an absence of evidence. We found no source that states a drying rule or a waiting time for permethrin-treated clothing with respect to pets. ### Who do you call after an exposure? Your veterinarian, NPIC, or an animal poison-control line. [EPA](https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet)'s flea and tick guidance says that if your pet experiences an adverse reaction, immediately bathe the pet with mild soap and rinse with large amounts of water, and contact your veterinarian, the National Pesticide Information Center at 1-800-858-7378, or both, right away. FDA says to call your veterinarian if your pet shows symptoms of illness after using a product, and to look for dizziness, wobbliness, incoordination, poor appetite, depression, vomiting, diarrhea or excessive salivation. NPIC says that for emergencies you should contact your veterinarian or the ASPCA Animal Poison Control Center at 1-888-426-4435. The ASPCA's own page gives the same number, 24 hours a day, 365 days a year, and says a consultation fee may apply. Pet Poison Helpline says it is available 24/7 at (855) 764-7661 and lists a one-time consultation fee of $89 per incident. For a cat, International Cat Care says that if you are worried you may have applied a flea product containing permethrin to your cat, or if your cat has been in contact with a dog treated with permethrin, contact your veterinary team immediately. ### Common questions **Is permethrin toxic after it dries?** No source we read gives a drying rule for permethrin-treated fabric with respect to pets, so we do not give one. The until-dry rules we found are about product applied to an animal: FDA says to keep a treated animal separated from other pets until the product dries, and the K9 Advantix II Medium Dog label says not to have contact with the treated area until completely dry. The clothing label we read, EPA Reg. No. 81402-1, says "Except when applying to clothing, do not allow adults or pets to enter until sprays have dried," which leaves clothing application out of that rule. **Can I use permethrin on my dog for fleas?** Some products carry EPA labels for exactly that, and the label and your veterinarian decide which. FDA says to read the label before use even if you have used the product many times before, because the directions or warnings may have changed, and NPIC says your veterinarian can help you compare and select the most appropriate products. **How long does one dog label say to keep a cat away from a treated dog?** One label we read gives a number, and the number is that label's alone. The K9 Advantix II Medium Dog label, EPA Reg. No. 11556-142, which lists permethrin among its active ingredients, says "Keep cats away from treated dogs for 24 hours," and "If applied to a cat or ingested by a cat, contact your veterinarian immediately." **Can I treat clothes with permethrin if I have a cat?** The label we read, EPA Reg. No. 81402-1, carries no cat instruction at all, so we do not turn its drying times into a rule for cats. What it does address is the person doing the treating: make all applications outdoors, never apply it to clothing while it is being worn, hang treated clothing to dry for at least 2 hours (4 hours under humid conditions) before wearing, and store the product away from children and pets. NPIC says to hang treated fabrics outdoors and allow them to dry completely before wearing them. ### Related reading - [Can I Put Mosquito Repellent on My Dog?](https://longsleeve.com/blog/can-i-put-mosquito-repellent-on-my-dog) - [Picaridin and Dogs: What the Label Decides](https://longsleeve.com/blog/is-picaridin-safe-for-dogs) - [Can I Use DEET on My Dog?](https://longsleeve.com/blog/can-i-use-deet-on-my-dog) - [Permethrin-Treated Clothing: How Often to Re-Treat, How Long It Lasts, and Why It Never Goes on Skin](https://longsleeve.com/blog/permethrin-clothing) ### Sources 1. NPIC, Permethrin General Fact Sheet. [https://npic.orst.edu/factsheets/PermGen.html](https://npic.orst.edu/factsheets/PermGen.html) 1. NPIC, Permethrin Treated Clothing. [https://npic.orst.edu/pest/mosquito/ptc.html](https://npic.orst.edu/pest/mosquito/ptc.html) 1. CDC, About Permethrin-Treated Clothing and Gear. [https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html](https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html) 1. AVMA, External Parasites. [https://www.avma.org/resources-tools/pet-owners/petcare/external-parasites](https://www.avma.org/resources-tools/pet-owners/petcare/external-parasites) 1. National Pesticide Information Center, Permethrin Technical Fact Sheet (archived), reviewed March 2009. [https://npic.orst.edu/factsheets/archive/Permtech.html](https://npic.orst.edu/factsheets/archive/Permtech.html) 1. US EPA stamped label, K9 Advantix II Medium Dog, EPA Reg. No. 11556-142, February 14, 2022 (PDF). [https://www3.epa.gov/pesticides/chem_search/ppls/011556-00142-20220214.pdf](https://www3.epa.gov/pesticides/chem_search/ppls/011556-00142-20220214.pdf) 1. US EPA, Read the Label First: Protect Your Pets. [https://www.epa.gov/pets/read-label-first-protect-your-pets](https://www.epa.gov/pets/read-label-first-protect-your-pets) 1. Sutton, Bates and Campbell, Clinical effects and outcome of feline permethrin spot-on poisonings reported to the Veterinary Poisons Information Service (VPIS), London, Journal of Feline Medicine and Surgery, 2007. [https://pmc.ncbi.nlm.nih.gov/articles/PMC10822630/](https://pmc.ncbi.nlm.nih.gov/articles/PMC10822630/) 1. US EPA, Reregistration Eligibility Decision (RED) for Permethrin, EPA 738-R-06-017, April 2006 (PDF). [https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/red_PC-109701_1-Apr-06.pdf](https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/red_PC-109701_1-Apr-06.pdf) 1. US EPA, EPA Evaluation of Pet Spot-on Products: Analysis and Plans for Reducing Harmful Effects. [https://www.epa.gov/pets/epa-evaluation-pet-spot-products-analysis-and-plans-reducing-harmful-effects](https://www.epa.gov/pets/epa-evaluation-pet-spot-products-analysis-and-plans-reducing-harmful-effects) 1. National Pesticide Information Center, Using Pesticides on Pets, last updated September 13, 2024. [https://npic.orst.edu/health/pets2.html](https://npic.orst.edu/health/pets2.html) 1. US FDA, Safe Use of Flea and Tick Products in Pets, content current as of 06/22/2021. [https://www.fda.gov/consumers/consumer-updates/safe-use-flea-and-tick-products-pets](https://www.fda.gov/consumers/consumer-updates/safe-use-flea-and-tick-products-pets) 1. US EPA, Controlling Fleas and Ticks on Your Pet. [https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet](https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet) 1. International Cat Care, Permethrin Poisoning, updated 26th Sep 2025. [https://icatcare.org/articles/permethrin-poisoning](https://icatcare.org/articles/permethrin-poisoning) 1. US EPA stamped label, Traveler's Supply Inc. Permethrin Clothing and Gear Insect Repellent, EPA Reg. No. 81402-1, stamped 08/27/2021 (PDF). [https://www3.epa.gov/pesticides/chem_search/ppls/081402-00001-20210827.pdf](https://www3.epa.gov/pesticides/chem_search/ppls/081402-00001-20210827.pdf) 1. ASPCA, Animal Poison Control. [https://www.aspca.org/pet-care/animal-poison-control](https://www.aspca.org/pet-care/animal-poison-control) 1. Pet Poison Helpline, About page. [https://www.petpoisonhelpline.com/about/](https://www.petpoisonhelpline.com/about/) Last reviewed 2026-09-21 · every claim on this page is sourced above ## Picaridin and Dogs: What the Label Decides URL: https://longsleeve.com/blog/is-picaridin-safe-for-dogs > EPA says do not use any product on pets unless the label clearly states it is for animals. The picaridin records we quote list human skin. Ask your vet. Source: https://longsleeve.com/blog/is-picaridin-safe-for-dogs By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 31, 2026 · Updated September 21, 2026 **Short answer:** EPA says not to use any product on pets or other animals unless the label clearly states it is for animals. EPA's picaridin fact sheet lists the application site as the human body, and both picaridin product records quoted below list human skin. For your dog, EPA says to consult your veterinarian about flea and tick protection. ### What do EPA and NPIC say about putting picaridin on a dog? [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively)'s answer is one sentence in its guidance on using insect repellents: "Do not use any product on pets or other animals unless the label clearly states it is for animals." The wording is "any product", with no exception for a particular active ingredient. NPIC's picaridin fact sheet describes what the ingredient does: it repels insects and makes them less likely to bite, it seems to block mosquitoes from sensing their prey, and it doesn't kill insects. [EPA](https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-070705_01-May-05.pdf)'s May 2005 fact sheet on picaridin lists the application site as the human body and the target pests as biting flies, mosquitoes, chiggers, ticks and fleas. NPIC's archived technical fact sheet says picaridin is registered for use on the human body and clothing. So the label on the product in your hand decides this, more than the name of the active ingredient. [NPIC](http://npic.orst.edu/factsheets/archive/Picaridintech.html)'s archived sheet says uses for individual picaridin products vary widely, and to always read and follow the label directions. For repellents and dogs more broadly, see [whether any mosquito repellent can go on a dog](https://longsleeve.com/blog/can-i-put-mosquito-repellent-on-my-dog). ### Which application sites do picaridin labels list? Human ones, in both product records we quote here. EPA's Pesticide Product and Label System record for Insect Guard 3023 Insect Repellent Lotion, EPA Reg. No. 54287-23, shows picaridin at 20 percent and lists its sites as human face area, human neck area and human skin. EPA's record for Natrapel 8 hour, EPA Reg. No. 56575-15, lists human clothing, human face area, human skin and outdoors. The [EPA](https://www3.epa.gov/pesticides/chem_search/ppls/054287-00023-20220215.pdf) stamped label for 54287-23 says: "It is a violation of Federal law to use this product in a manner inconsistent with its labeling." Its directions say to apply evenly to skin in a thin layer and not to exceed two applications per day; how long an application holds on a person is covered in [how long picaridin lasts](https://longsleeve.com/blog/how-long-does-picaridin-last). EPA's picaridin fact sheet says why those label directions are written the way they are. It says that because of picaridin's unusual use pattern, direct application to human skin, the Agency believes it is prudent to require clear, common sense use directions and restrictions on picaridin product labels. The word EPA chose is human. We found no EPA-registered picaridin product whose label lists dogs, cats or horses. That describes what we read, and what we read has limits: EPA's list of skin-applied repellent ingredients shows picaridin with about 40 products, and EPA says its repellent search tool includes only skin-applied repellent products registered by EPA. ### What did the dog testing on picaridin actually cover? Skin toxicity, a different question from whether a repellent product may go on your dog. Two records describe dermal testing in dogs. NPIC's archived technical fact sheet says researchers placed technical grade picaridin at doses of 50, 100 or 200 mg/kg on the backs of beagle dogs every weekday for one year, and the dogs demonstrated no adverse effects at any dose. EPA's May 2005 fact sheet records a dermal chronic toxicity study in dogs with a systemic NOAEL of 200 mg/kg/day and states, "No toxicity was observed." Two cautions go with those records. NPIC stopped creating technical fact sheets as of 2011 and says the archived collection may contain out-of-date material, so treat its sheet accordingly. A study in beagles is not permission to use a product on a dog. We found no agency source that says it is. In other species, NPIC's picaridin fact sheet says researchers applied large amounts to the skin of rats and rabbits for up to two years, and the parent animals' skin got thicker, became irritated and developed dark spots. In rats, NPIC reports, 60 percent of the picaridin applied to skin went through it; in humans, less than 6 percent was absorbed. Neither figure describes a dog. [NPIC](https://npic.orst.edu/health/animhealth.html)'s general guidance on animals holds here: all pesticides have some level of toxicity, even the least-toxic products can cause health problems if an animal is exposed to enough of it, and some animals may be more sensitive than others to certain pesticides. For DEET, see [what the agencies say about DEET and dogs](https://longsleeve.com/blog/can-i-use-deet-on-my-dog). ### What should go on the dog instead? A product labeled for your dog, chosen with your veterinarian. [EPA](https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet) says to use flea and tick control products only on the animal species and size or weight specified by the product label. FDA says to make sure the product matches your pet's species, life stage and weight class. EPA states it directly: never apply dog products to cats, and vice versa, as some pesticides are more toxic to one species than another. On cats and picaridin specifically, we found no agency statement in either direction, so this page does not characterize it. [FDA](https://www.fda.gov/consumers/consumer-updates/safe-use-flea-and-tick-products-pets) describes the labeled options: flea and tick products range from pills and chews given by mouth to collars, sprays, dips, shampoos, powders and spot-ons. All three sources send you to the same person. FDA says it is strongly recommended that you involve your veterinarian when choosing a flea and tick product, especially if your pet has any health conditions. EPA says to consult your veterinarian about the best way to protect your pets from fleas and ticks, and [NPIC](https://npic.orst.edu/health/pets2.html) says your veterinarian can help you compare and select the most appropriate products to control insects and ticks on your pets. ### What do the agencies say to do if your dog is exposed? Call the National Pesticide Information Center, NPIC. [NPIC](https://npic.orst.edu/health/petpoison.html) says that if you know or suspect your animal was exposed to a pesticide, call NPIC to discuss the incident and learn about the potential risk to your pet. For an adverse reaction, EPA's flea and tick page says to contact your veterinarian and/or NPIC at 1-800-858-7378 right away, and to immediately bathe the pet with mild soap and rinse with large amounts of water. For emergencies, NPIC says to contact a veterinarian or one of its animal emergency resources, then NPIC once your pet has received medical attention. NPIC lists the ASPCA Animal Poison Control Center at 888-426-4435 and the Pet Poison Helpline at 855-764-7661, and notes a consultation fee may apply to each. FDA says to call your veterinarian if your pet shows symptoms of illness after using a product, and to look for dizziness, wobbliness, incoordination, poor appetite, depression, vomiting, diarrhea or excessive salivation. NPIC's perspective: used according to the label directions, pesticides used around the home or on pets should pose little risk, but even careful use can cause harm to a sensitive, ill or injured animal. We found no agency statement about picaridin and a dog licking treated human skin, and no threshold or home protocol for it. In an emergency, NPIC says, contact a veterinarian. ### What about our own EPA registration? Our registration is for Longsleeve Repellent, EPA Reg. No. 101457-1; EPA's product record lists picaridin at 20 percent. EPA lists the application site for picaridin as the human body, and says not to use any product on pets or other animals unless the label clearly states it is for animals. So it does not go on a dog. ### Common questions **Can I spray picaridin on my dog?** Not unless the label on that product clearly states it is for animals, which is EPA's guidance for any product. Both picaridin product records quoted on this page list human skin and human face area among their sites. **Is picaridin toxic to cats?** We found no agency statement that names cats and picaridin together, so we will not characterize it in either direction. On species in general, NPIC says dog products should never be used on cats and that certain pesticides are more toxic to one species compared to the other, and EPA says never to apply dog products to cats, and vice versa. **How long after mosquito spray can I let my dog out?** Until the pesticide is completely dry and the area has been well ventilated: that is NPIC 's guidance for keeping pets away from treated areas, and NPIC adds that the label may contain more specific instructions. This is about yard and area sprays, a different product from a skin repellent; NPIC also says to remove pets from the area before you begin applying pesticides. For granular lawn products, NPIC says pets may need to stay off for 24 hours or longer while the granules dissolve and the treated area dries. **What are the side effects of picaridin?** In people, NPIC says some have had skin irritation from products containing picaridin, although this is very uncommon, and that picaridin in the eyes may also cause irritation. NPIC 's insect repellents fact sheet says repellents are low or very low in toxicity when used on the skin. Both statements are about people, and neither describes a dog or a cat. **Is icaridin the same as picaridin?** Yes. NPIC's archived technical fact sheet says the World Health Organization refers to this chemical as icaridin, and the same sheet says picaridin is registered for use on the human body and clothing. **Is picaridin the same as permethrin?** No. NPIC says permethrin is an insecticide in the pyrethroid family, used in cattle ear tags and flea collars, or in spot-on treatments for dogs, while NPIC says picaridin repels insects and doesn't kill them. NPIC also says cats are more sensitive to permethrin than dogs or people, because it takes their bodies a long time to break it down. Permethrin has its own page: what the agencies say about permethrin around pets . ### Related reading - [Can I Put Mosquito Repellent on My Dog?](https://longsleeve.com/blog/can-i-put-mosquito-repellent-on-my-dog) - [Can I Use DEET on My Dog?](https://longsleeve.com/blog/can-i-use-deet-on-my-dog) - [Permethrin Around Dogs and Cats: What the Labels Say](https://longsleeve.com/blog/is-permethrin-safe-around-pets) - [How Long Does Picaridin Last? Skin, Clothes, and Shelf Life](https://longsleeve.com/blog/how-long-does-picaridin-last) ### Sources 1. EPA, Skin-Applied Repellent Ingredients. [https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. NPIC, Picaridin Fact Sheet. [https://npic.orst.edu/factsheets/PicaridinGen.html](https://npic.orst.edu/factsheets/PicaridinGen.html) 1. NPIC, Insect Repellents Fact Sheet. [https://npic.orst.edu/factsheets/repellents.html](https://npic.orst.edu/factsheets/repellents.html) 1. NPIC, Picaridin Technical Fact Sheet (archived), reviewed March 2009. [http://npic.orst.edu/factsheets/archive/Picaridintech.html](http://npic.orst.edu/factsheets/archive/Picaridintech.html) 1. EPA, New Pesticide Fact Sheet: Picaridin, May 2005 (PDF). [https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-070705_01-May-05.pdf](https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-070705_01-May-05.pdf) 1. EPA, Using Insect Repellents Safely and Effectively, updated November 10, 2025. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. EPA Pesticide Product and Label System, Insect Guard 3023 Insect Repellent Lotion, EPA Reg. No. 54287-23. [https://ordspub.epa.gov/ords/pesticides/f?p=PPLS:102:::NO::P102_REG_NUM:54287-23](https://ordspub.epa.gov/ords/pesticides/f?p=PPLS:102:::NO::P102_REG_NUM:54287-23) 1. EPA stamped label, Insect Guard 3023 Insect Repellent Lotion, EPA Reg. No. 54287-23, accepted February 15, 2022 (PDF). [https://www3.epa.gov/pesticides/chem_search/ppls/054287-00023-20220215.pdf](https://www3.epa.gov/pesticides/chem_search/ppls/054287-00023-20220215.pdf) 1. EPA Pesticide Product and Label System, Natrapel 8 hour, EPA Reg. No. 56575-15. [https://ordspub.epa.gov/ords/pesticides/f?p=PPLS:102:::NO::P102_REG_NUM:56575-15](https://ordspub.epa.gov/ords/pesticides/f?p=PPLS:102:::NO::P102_REG_NUM:56575-15) 1. EPA Pesticide Product and Label System, label record for EPA Reg. No. 101457-1. [https://ordspub.epa.gov/ords/pesticides/f?p=PPLS:102:::NO::P102_REG_NUM:101457-1](https://ordspub.epa.gov/ords/pesticides/f?p=PPLS:102:::NO::P102_REG_NUM:101457-1) 1. EPA, Controlling Fleas and Ticks on Your Pet, updated June 10, 2026. [https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet](https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet) 1. FDA, Safe Use of Flea and Tick Products in Pets, current as of June 22, 2021. [https://www.fda.gov/consumers/consumer-updates/safe-use-flea-and-tick-products-pets](https://www.fda.gov/consumers/consumer-updates/safe-use-flea-and-tick-products-pets) 1. NPIC, Using Pesticides on Pets, updated September 13, 2024. [https://npic.orst.edu/health/pets2.html](https://npic.orst.edu/health/pets2.html) 1. NPIC, Pesticide Use Around Pets, updated April 14, 2026. [https://npic.orst.edu/health/pets.html](https://npic.orst.edu/health/pets.html) 1. NPIC, Pesticide Poisoning in Pets, updated February 03, 2025. [https://npic.orst.edu/health/petpoison.html](https://npic.orst.edu/health/petpoison.html) 1. NPIC, Pesticides and Animal Health, updated August 06, 2025. [https://npic.orst.edu/health/animhealth.html](https://npic.orst.edu/health/animhealth.html) 1. NPIC, Permethrin General Fact Sheet. [http://npic.orst.edu/factsheets/PermGen.html](http://npic.orst.edu/factsheets/PermGen.html) Last reviewed 2026-09-21 · every claim on this page is sourced above ## Lone Star Tick: Identification, Range, Bites, and Alpha-Gal Link URL: https://longsleeve.com/blog/lone-star-tick > How to identify the lone star tick, where it lives in the U.S., how it bites, which CDC-listed diseases are linked to it, and its association with alpha-gal syndrome. Source: https://longsleeve.com/blog/lone-star-tick By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 16, 2026 **Short answer:** The lone star tick is *Amblyomma americanum*, a CDC-described aggressive human-biting tick. Adult females have a single white dot on the back. The CDC reports it is widely distributed in the Northeast, South, and Midwest, and links it to ehrlichiosis, Heartland virus, Bourbon virus, tularemia, STARI, and the U.S. tick most often associated with alpha-gal syndrome. ### How do you identify a lone star tick? The adult female is the easy one. The CDC notes she is distinguished by a white dot, the namesake "lone star," on her back. The Illinois Department of Public Health describes adult lone star ticks as about 1/8 inch long and brown, with the female's white spot sitting in the middle of her back. The younger stages are much harder to see. Per the Illinois Department of Public Health, a larva is only a little larger than the period at the end of a sentence, and a nymph, the most common stage found on people, is about the size of a pinhead. That small size causes real confusion. The Illinois Department of Public Health notes that lone star ticks are sometimes misidentified as blacklegged ticks, better known as deer ticks, because the two are so similar in size. If you saved the specimen and want to know what bit you, our guide to [tick identification](https://longsleeve.com/blog/tick-identification) walks through the lookalikes. ### Where do lone star ticks live? The [CDC](https://www.cdc.gov/ticks/data-research/facts-stats/lone-star-tick-surveillance.html) reports the lone star tick widely distributed in the Northeast, South, and Midwest United States. The University of Rhode Island's TickEncounter program points to a 2014 study that found lone star ticks as far west as Colorado and Wyoming and as far north as Maine. In the South, this is the tick that finds you. TickEncounter reports that lone star ticks are the main human-biting ticks in the southeastern and south-central United States, accounting for over 90 percent of reported tick bites in the south. Up close, they favor cover. TickEncounter describes lone star ticks living mostly in woodlands with dense undergrowth and around animal resting areas. Their comeback story runs through deer. The CDC calls white-tailed deer a keystone host for this tick. Since the 1940s, conservation measures and deer relocation have increased white-tailed deer numbers and range in the eastern United States, and as the deer rebounded, the lone star tick repopulated its historical range. ### How does a lone star tick get on you? Not by flying or jumping. The CDC explains that ticks can do neither; instead, many species wait in a posture called questing, gripping leaves and grass with their back pairs of legs while holding the front pair outstretched, ready to climb aboard whatever brushes past. TickEncounter notes adult lone star ticks quest for larger animals, humans included, on tall grass in shade or at the tips of low branches. Per the [CDC](https://www.cdc.gov/ticks/about/tick-lifecycles.html), most ticks move through four life stages: egg, six-legged larva, eight-legged nymph, and adult. After hatching, they must eat blood at every stage to survive. Lone star ticks aggressively bite people as larvae, nymphs, and adults, and the nymphs and adult females are the stages that most frequently bite humans and transmit disease. The mechanics matter. The CDC explains that ticks usually acquire pathogens as larvae or nymphs while feeding on animals, then pass those pathogens to people at later stages. TickEncounter notes that lone star larvae do not carry disease-causing germs, though they still inject allergy-provoking saliva when they bite. ### What diseases are linked to the lone star tick? Per the [CDC](https://www.cdc.gov/ticks/about/where-ticks-live.html), the lone star tick transmits Bourbon virus, Ehrlichia chaffeensis and Ehrlichia ewingii (the bacteria behind human ehrlichiosis), Heartland virus, and tularemia. A circular rash of unknown cause, called STARI, sometimes follows its bite. - **Ehrlichiosis.** The CDC describes ehrlichiosis as a group of diseases caused by Ehrlichia bacteria, spread to people primarily through bites of infected ticks, including the lone star tick and the blacklegged tick. People with ehrlichiosis often have fever, chills, headache, and muscle aches, and sometimes an upset stomach. - **STARI.** The CDC says the cause of southern tick-associated rash illness is not known, but it is specifically associated with lone star tick bites. The rash is a red, expanding lesion around the bite site that usually appears within 7 days and grows to 3 to 12 inches across. - **Heartland virus.** It spreads to people through bites of infected ticks, primarily lone star ticks, per the CDC. There is no vaccine to prevent it and no medicine to treat it. - **Bourbon virus.** The CDC says Bourbon virus is believed to spread through bites of infected ticks, likely lone star ticks. It was discovered in 2014 and named for Bourbon County, Kansas, where it was first identified. - **Tularemia.** A potentially serious illness caused by the bacterium Francisella tularensis. The CDC lists the lone star tick among the U.S. ticks that transmit it, alongside the dog tick and the wood tick. This is not a rare-event category: the [CDC](https://www.cdc.gov/ticks/communication-resources/press-kit.html) estimates that nearly half a million people are diagnosed and treated for a tickborne disease each year. If you develop a fever, an expanding rash, or other symptoms after a tick bite, talk to a clinician. And if a tick is still attached, our [tick removal](https://longsleeve.com/blog/tick-removal) guide covers the calm, correct way to get it off. ### Does the lone star tick cause red meat allergy? This one deserves the CDC's exact caution. Alpha-gal syndrome (AGS) is a serious, potentially life-threatening allergy that can develop after a tick bite. On causation, the [CDC](https://www.cdc.gov/alpha-gal-syndrome/about/index.html)'s wording is deliberate: AGS is caused by tick bites, "though more research is needed to understand the role ticks play." In the United States, the lone star tick is the tick most often associated with AGS, with a few cases reported after bites from blacklegged and western blacklegged ticks. The CDC's press materials carry the same hedge: growing evidence suggests that alpha-gal syndrome may be triggered by the bite of lone star ticks, and possibly other tick species. The geography supports the association. A [CDC](https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a2.htm) analysis in MMWR found suspected AGS cases predominantly located in areas where the lone star tick is established or reported, and most reported U.S. cases occur in South, East, and Central states, the same areas where most lone star ticks are found. In a recent study the CDC's press materials cite, the states with the highest rates of positive alpha-gal antibody tests were Arkansas, Virginia, Kentucky, Oklahoma, and Missouri. More than 110,000 suspected AGS cases were identified between 2010 and 2022, and because cases are not nationally notifiable to the CDC, the true number is unknown; as many as 450,000 people may be affected. Not every person bitten by a lone star tick develops AGS, and the reason some people develop it while others do not is not known. For the full picture, read our explainer on [alpha-gal syndrome](https://longsleeve.com/blog/alpha-gal-syndrome), and bring any new allergic symptoms after a tick bite to a clinician. ### When are lone star ticks active? The [CDC](https://www.cdc.gov/ticks/prevention/index.html) notes tick exposure can occur year-round, but ticks are most active during the warmer months, April through September. TickEncounter puts adult lone star ticks on the move from April to late August, questing for larger animals on shaded tall grass and low branches. For a month-by-month breakdown, see our guide to [when tick season peaks](https://longsleeve.com/blog/tick-season-when). ### How do you prevent lone star tick bites? The CDC's playbook, in the order you would use it: - **Before you go out.** The CDC recommends EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone. It also recommends treating clothing and gear with 0.5% permethrin, which stays protective through several washings, or buying permethrin-treated clothing. More on that approach in our guide to [permethrin-treated clothing](https://longsleeve.com/blog/permethrin-clothing). - **While you are out.** The CDC advises avoiding wooded and brushy areas with high grass and leaf litter, and walking in the center of trails. - **When you get home.** The CDC notes showering within two hours of coming indoors has been shown to reduce the risk of Lyme disease and may reduce the risk of other tickborne diseases. Then do a full-body tick check with a mirror after any potentially tick-infested area, including your own backyard. On the repellent step: Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours, and it is fragrance free, with nine disclosed ingredients. ### Frequently asked questions **Is STARI the same as Lyme disease?** No. The CDC says studies show STARI is not caused by the bacteria that cause Lyme disease (Borrelia burgdorferi). Lone star ticks have not been shown to transmit B. burgdorferi, and their saliva has actually been shown to kill Borrelia. The cause of STARI is not known, but it is specifically associated with lone star tick bites. **Does every lone star tick bite cause alpha-gal syndrome?** No. The CDC states that not every person bitten by a lone star tick will develop AGS, and the reason some people develop it while others do not is not known. The CDC's framing is that growing evidence suggests AGS may be triggered by lone star tick bites, and that more research is needed to understand the role ticks play. If you notice new allergic symptoms after a bite, talk to a clinician. **The bite site is red and itchy. Does that mean I am infected?** Not necessarily. The CDC notes lone star tick saliva can be irritating on its own, and redness and discomfort at a bite site does not necessarily indicate an infection. If a fever, an expanding rash, or other symptoms follow, see a clinician. **Can lone star ticks jump or fly?** No. Per the CDC, ticks cannot fly or jump. They wait in a questing posture, holding onto leaves and grass with their back legs and stretching their front legs outward to grab a passing host. **How many people get sick from tick bites each year?** The CDC estimates nearly half a million people are diagnosed and treated for a tickborne disease each year. ### Related reading - [Alpha-Gal Syndrome Timeline](https://longsleeve.com/blog/alpha-gal-syndrome). How long after a tick bite symptoms start, and whether it goes away. - [Ehrlichiosis](https://longsleeve.com/blog/ehrlichiosis). Symptoms, lone star tick link, treatment, and prevention. - [Tick Identification Guide](https://longsleeve.com/blog/tick-identification). Species, pictures, regions, and risks. - [How to Remove a Tick](https://longsleeve.com/blog/tick-removal). Tweezers, timing, and what not to do. - [The species almanac](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. CDC, Lone Star Tick Surveillance: [cdc.gov/ticks/data-research/facts-stats/lone-star-tick-surveillance.html](https://www.cdc.gov/ticks/data-research/facts-stats/lone-star-tick-surveillance.html) 1. CDC, Where Ticks Live: [cdc.gov/ticks/about/where-ticks-live.html](https://www.cdc.gov/ticks/about/where-ticks-live.html) 1. CDC, About Ticks: [cdc.gov/ticks/about/index.html](https://www.cdc.gov/ticks/about/index.html) 1. CDC, Tick Lifecycles: [cdc.gov/ticks/about/tick-lifecycles.html](https://www.cdc.gov/ticks/about/tick-lifecycles.html) 1. CDC, Preventing Tick Bites: [cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. CDC, About Ehrlichiosis: [cdc.gov/ehrlichiosis/about/index.html](https://www.cdc.gov/ehrlichiosis/about/index.html) 1. CDC, About STARI: [cdc.gov/stari/about/index.html](https://www.cdc.gov/stari/about/index.html) 1. CDC, About Heartland Virus: [cdc.gov/heartland-virus/about/index.html](https://www.cdc.gov/heartland-virus/about/index.html) 1. CDC, About Bourbon Virus: [cdc.gov/bourbon-virus/about/index.html](https://www.cdc.gov/bourbon-virus/about/index.html) 1. CDC, About Tularemia: [cdc.gov/tularemia/about/index.html](https://www.cdc.gov/tularemia/about/index.html) 1. CDC, Causes of Tularemia: [cdc.gov/tularemia/causes/index.html](https://www.cdc.gov/tularemia/causes/index.html) 1. CDC, About Alpha-gal Syndrome: [cdc.gov/alpha-gal-syndrome/about/index.html](https://www.cdc.gov/alpha-gal-syndrome/about/index.html) 1. CDC, MMWR analysis of suspected alpha-gal syndrome cases: [cdc.gov/mmwr/volumes/72/wr/mm7230a2.htm](https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a2.htm) 1. CDC, Tick Press Kit: [cdc.gov/ticks/communication-resources/press-kit.html](https://www.cdc.gov/ticks/communication-resources/press-kit.html) 1. Illinois Department of Public Health, Common Ticks: [dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/common-ticks.html](https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/common-ticks.html) 1. University of Rhode Island TickEncounter, Lone Star Tick: [web.uri.edu/tickencounter/species/lone-star-tick/](https://web.uri.edu/tickencounter/species/lone-star-tick/) Last reviewed 2026-08-16 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Lyme Disease Prevention: Tick Checks, Repellent, Permethrin URL: https://longsleeve.com/blog/lyme-disease-prevention > CDC-sourced Lyme disease prevention steps: avoid tick habitat, use EPA-registered repellent, treat clothing with permethrin, check for ticks, and remove attached ticks promptly. Source: https://longsleeve.com/blog/lyme-disease-prevention By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 5, 2026 · Updated August 16, 2026 **Short answer:** Lyme disease spreads through infected blacklegged ticks. The CDC says infected ticks generally must be attached for more than 24 hours before they transmit the bacteria, which is why prevention is layered: avoid tick habitat, use EPA-registered repellent, treat clothing and gear with 0.5 percent permethrin, check your body after being outdoors, and remove attached ticks promptly. ### How does Lyme disease actually get into a person? In the United States, Lyme disease is caused by the bacterium *Borrelia burgdorferi* and, rarely, *Borrelia mayonii*, spread to people through the bites of infected ticks. The blacklegged tick, also called the deer tick (*Ixodes scapularis*), transmits infection in the northeastern, mid-Atlantic, and north-central United States. The western blacklegged tick (*Ixodes pacificus*) does so along the Pacific Coast. Not every tick carries anything. The [CDC](https://www.cdc.gov/lyme/causes/index.html) says the percentage of ticks that are infected ranges from none to over 50%, depending on the area and life stage, and that blacklegged ticks in most areas of the southeastern United States are almost never infected. Several ticks people worry about cannot transmit Lyme at all: the CDC lists the lone star tick, the American dog tick, the Rocky Mountain wood tick, and the brown dog tick as unable to transmit Lyme disease bacteria. The CDC calls Lyme disease the leading cause of tickborne disease in the United States, with an estimated 476,000 infections diagnosed and treated each year. ### How long does a tick have to be attached to transmit Lyme? This is the number that makes a daily tick check worth two minutes. The CDC states that in general, infected ticks must be attached for more than 24 hours to transmit infection, and that prompt tick removal can prevent transmission. In its own words: "If you remove a tick within 24 hours, you can greatly reduce your chances of getting Lyme disease." The catch is that the riskiest ticks are the ones you are least likely to spot. Nymphal ticks pose a particularly high risk due to their abundance and small size, about the size of a poppy seed. In areas of the eastern United States where Lyme disease is common, the CDC says nymphs are actively questing for hosts from April through July. The CDC notes that Lyme disease patients are often not even aware of a tick bite before getting sick. Adult females can also transmit the bacteria, but at roughly the size of a sesame seed they are more likely to be noticed and removed first. ### Where and when do people pick ticks up? Ticks live in grassy, brushy, or wooded areas, or even on animals. Exposure can happen year-round, but ticks are most active during the warmer months of April through September, and the CDC notes blacklegged ticks can bite any time winter temperatures are above freezing. The [CDC](https://www.cdc.gov/lyme/prevention/index.html) also says many who develop Lyme disease are exposed in their own yards or neighborhoods, not just in wooded or rural areas. ### What are the prevention layers, in order? #### 1. Avoid the habitat where you can The [CDC](https://www.cdc.gov/ticks/prevention/index.html) recommends avoiding wooded and brushy areas with high grass and leaf litter, and walking in the center of trails. #### 2. Put fabric between you and the tick The [EPA](https://www.epa.gov/insect-repellents/tips-prevent-tick-bites) recommends keeping ticks away from exposed skin by wearing long-sleeved shirts, long pants, and high boots, tucking shirts into pants and pants into socks to cover the gaps where ticks get in, and wearing light-colored clothing so ticks are easier to see. #### 3. Treat clothing and gear with 0.5% permethrin The CDC recommends treating clothing and gear with products containing 0.5% permethrin. It can be used on boots, clothing, and camping gear, and remains protective through several washings. You can also buy [permethrin-treated clothing and gear](https://longsleeve.com/blog/permethrin-clothing). One rule is not optional: do not use permethrin products directly on skin. #### 4. Use an EPA-registered repellent on skin The CDC recommends EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone, and looking for an EPA registration number (EPA Reg. No.) on the label. That number means the company provided EPA with technical information on the effectiveness of the product. Application details matter. The EPA says to follow the label directions, apply only to exposed skin and clothing rather than under clothing, avoid applying near eyes and mouth, spray on hands first and then apply to the face, never use repellents over cuts, wounds, or irritated skin, and wash treated skin and clothes with soap and water after returning indoors. For children, apply to your own hands first rather than to the child's hands. The CDC adds that sunscreen goes on first and repellent second, and that products containing OLE or PMD should not be used on children under 3 years old. #### 5. Run the indoor routine every time This is the layer people skip, and it catches what the others missed. - **Check your clothing.** Tumble dry clothes on high heat for 10 minutes to kill ticks on dry clothing. Damp clothes may need additional time. If clothes need washing first, hot water is recommended, because cold and medium temperature water will not kill ticks. - **Examine gear and pets.** Ticks ride into the home on clothing and pets and attach to a person later, so check pets, coats, and daypacks. - **Shower soon after being outdoors.** The CDC states that showering within two hours of coming indoors has been shown to reduce your risk of getting Lyme disease and may be effective in reducing the risk of other tickborne diseases. - **Do a full body check.** Use a hand-held or full-length mirror. The CDC's checklist covers under the arms, in and around the ears, inside the belly button, back of the knees, in and around the hair, between the legs, and around the waist. The CDC also suggests running a lint roller over your skin, clothing, and gear to pick up unattached ticks you cannot see. ### What is the correct way to remove a tick? Speed beats technique. The CDC says to remove the tick as soon as possible and not to wait for a healthcare provider, because delaying removal could increase your risk. 1. Grasp the tick as close to the skin's surface as possible with clean fine-tipped tweezers. If you do not have them, the CDC says regular tweezers or your fingers will work, grasping close to the skin to avoid squeezing the tick's body. 1. Pull away from the skin with steady, even pressure. Do not twist or jerk, which can break off the mouthparts and leave them in the skin. If that happens, your body will push them out over time, and if you cannot remove them easily with tweezers, leave them alone. 1. Dispose of the live tick in a sealed container, wrapped tightly in tape, flushed down the toilet, or in alcohol. Do not crush it with your fingers. 1. Clean the bite area and your hands with soap and water, rubbing alcohol, or hand sanitizer, then check for other ticks. The CDC notes that finding one means there may be others. The [CDC](https://www.cdc.gov/ticks/after-a-tick-bite/index.html) warns against petroleum jelly, heat, nail polish, or other substances meant to make the tick detach, because this may agitate the tick and force infected fluid into the skin. It also advises against sending the tick for testing, and says that if you do become ill, you should not wait for tick testing results before beginning appropriate treatment. ### What early symptoms mean it is time to call a doctor? Early signs appear 3 to 30 days after a tick bite. The [CDC](https://www.cdc.gov/lyme/signs-symptoms/index.html) lists fever, chills, headache, fatigue, muscle and joint aches, and swollen lymph nodes, which may occur in the absence of rash. The erythema migrans (EM) rash occurs in approximately 70 to 80 percent of infected people. It begins at the bite site after a delay of 3 to 30 days, averaging about 7 days, and expands gradually over several days, reaching up to 12 inches (30 cm) or more across. It may feel warm to the touch but is rarely itchy or painful, and it sometimes clears as it enlarges, producing the target or "bull's-eye" look. The CDC is clear that it does not always appear as a classic bull's-eye and may show up anywhere on the body. Do not confuse it with the ordinary bite reaction: a small bump or redness that appears immediately and resembles a mosquito bite is common, generally goes away in 1 to 2 days, and is not a sign of Lyme disease. Later signs, days to months after a bite, include severe headaches and neck stiffness, additional EM rashes elsewhere on the body, facial palsy, arthritis with severe joint pain and swelling particularly in the knees, heart palpitations or an irregular heartbeat, dizziness or shortness of breath, nerve pain, and shooting pains, numbness, or tingling in the hands or feet. The CDC's rule of thumb: if you develop a rash or fever within several weeks of removing a tick, see your doctor, and tell them about the bite, when it occurred, and where you most likely acquired the tick. The outlook with care is good. The [CDC](https://www.cdc.gov/lyme/about/index.html) states that most cases of Lyme disease can be treated successfully with a few weeks of antibiotics. In certain circumstances a single dose of doxycycline after a tick bite in an area where Lyme disease is common may lower risk, and the CDC advises asking your healthcare provider whether that is appropriate for you. ### Common questions **If I pulled the tick off the same day, am I in the clear?** The CDC states that in most cases a tick must be attached more than 24 hours before the Lyme disease bacterium can be transmitted, and that removing it within 24 hours greatly reduces your chances. Still watch for a rash or fever in the weeks afterward and see your doctor if either appears. **Does Lyme always start with a bull's-eye rash?** No. The EM rash occurs in approximately 70 to 80 percent of infected people, and the CDC notes it does not always appear as a classic bull's-eye. Fever, chills, headache, fatigue, muscle and joint aches, and swollen lymph nodes may occur in the absence of rash. **Do ticks shut down in winter?** Not entirely. Tick exposure can occur year-round, and the CDC notes blacklegged ticks can be active and bite people any time winter temperatures are above freezing. ### About Longsleeve Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients. Nothing on this page is medical advice. If you have been bitten by a tick, or you have symptoms you are worried about, talk to a clinician. ### Related reading - [The Two-Layer System](https://longsleeve.com/blog/permethrin-picaridin-system). Why the CDC pairs treated clothing with skin repellent. - [Vector-Borne Disease in the US, by the Numbers](https://longsleeve.com/blog/vector-borne-disease-numbers). One million reported cases, and what the CDC's counts actually measure. - [How to Remove a Tick](https://longsleeve.com/blog/tick-removal). Fine-tipped tweezers, straight out, and what to watch for after. - [When Is Tick Season?](https://longsleeve.com/blog/tick-season-when). Why nymphs drive most disease, and why checks matter year round. - [The almanac of biting insects](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. CDC, How Lyme Disease Spreads. [https://www.cdc.gov/lyme/causes/index.html](https://www.cdc.gov/lyme/causes/index.html) 1. CDC, Preventing Lyme Disease. [https://www.cdc.gov/lyme/prevention/index.html](https://www.cdc.gov/lyme/prevention/index.html) 1. CDC, Preventing Tick Bites. [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. CDC, Signs and Symptoms of Untreated Lyme Disease. [https://www.cdc.gov/lyme/signs-symptoms/index.html](https://www.cdc.gov/lyme/signs-symptoms/index.html) 1. CDC, What to Do After a Tick Bite. [https://www.cdc.gov/ticks/after-a-tick-bite/index.html](https://www.cdc.gov/ticks/after-a-tick-bite/index.html) 1. CDC, About Lyme Disease. [https://www.cdc.gov/lyme/about/index.html](https://www.cdc.gov/lyme/about/index.html) 1. CDC, About Permethrin-Treated Clothing and Gear. [https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html](https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html) 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. EPA, Tips to Prevent Tick Bites. [https://www.epa.gov/insect-repellents/tips-prevent-tick-bites](https://www.epa.gov/insect-repellents/tips-prevent-tick-bites) Last reviewed 2026-08-05 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Malaria Prevention for Travelers: CDC Yellow Book Checklist URL: https://longsleeve.com/blog/malaria-prevention-travelers > CDC guidance on malaria prevention for travelers: chemoprophylaxis plus bite avoidance, yellow fever versus malaria, and how to read the country row. Source: https://longsleeve.com/blog/malaria-prevention-travelers By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 16, 2026 · Updated September 13, 2026 The [CDC](https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/malaria.html) says malaria prevention consists of a combination of mosquito avoidance measures and chemoprophylaxis, meaning prescription antimalarial medicine. *Anopheles* mosquitoes feed at night, so nets, screens, and repellent matter after dark. Which drug fits depends on your destination and your health history, so a clinician decides. Any fever in the year after travel means immediate medical attention. About 2,000 cases of malaria are diagnosed in the United States in a typical year, and the CDC Yellow Book says almost all of them are imported. Its framing: interventions are highly efficacious, but not 100% effective. That is why CDC pairs the medicine and the mosquito net rather than treating either one as sufficient. ### Where is malaria actually a risk? The [WHO](https://www.who.int/news-room/fact-sheets/detail/malaria) counted an estimated 282 million malaria cases and 610,000 malaria deaths in 80 countries in 2024. The WHO African Region carried 95% of cases, 265 million, and 95% of deaths, 579,000. Children under 5 accounted for about 75% of malaria deaths in that region. That 75% is scoped to the African Region. **Short answer:** CDC guidance says malaria prevention combines mosquito avoidance measures with chemoprophylaxis, meaning prescription antimalarial medicine. *Anopheles* mosquitoes feed at night, so nets, screens, and repellent matter after dark. Which medicine fits depends on destination and health history, so a clinician decides. Any fever in the year after travel needs immediate medical attention. The Yellow Book: "Malaria transmission is not distributed homogeneously throughout a country, so review the exact itinerary to determine if travel will occur in highly endemic areas." CDC's Yellow Book chapter Malaria Prevention Information, by Country breaks risk down to the specific parts of countries where malaria spreads, the species present, and local drug resistance. That chapter is what a travel clinician works from. ### Yellow fever and malaria: two mosquitoes, two defenses Different pathogen, different mosquito, different defense. The CDC Yellow Book says yellow fever virus is a *Flavivirus* spread primarily by *Aedes* or *Haemagogus* mosquitoes and preventable by vaccine; malaria is *Plasmodium* species transmitted by an infective female *Anopheles* mosquito, and its prevention is mosquito-avoidance measures plus chemoprophylaxis. | Disease | Mosquito | When it bites | Prevention tool | |---|---|---|---| | Yellow fever, a *Flavivirus* | Primarily *Aedes* or *Haemagogus*; [Aedes aegypti](https://longsleeve.com/blog/aedes-aegypti) in the urban cycle | CDC: peak biting after sunrise and at sunset. WHO: day-biting | CDC: vaccine, if vaccination is recommended for you, plus preventing bites | | Malaria, *Plasmodium* parasites | Infective female *Anopheles* | CDC: mainly between dusk and dawn; peak during the night or evening hours | CDC: mosquito avoidance plus chemoprophylaxis. CDC: no vaccine for malaria currently available in the U.S. | The two agencies word the yellow fever mosquito's clock differently. The CDC Yellow Book says peak biting of *Aedes aegypti*, the primary vector for yellow fever and [dengue](https://longsleeve.com/blog/dengue-travel), is after sunrise and at sunset. The [WHO](https://www.who.int/news-room/fact-sheets/detail/yellow-fever) says yellow fever is primarily transmitted by day-biting mosquitoes, and that insecticide-treated bed nets are less effective against it because those mosquitoes bite during the daytime. The CDC's own caution covers the overlap, which is why the two diseases do not split the clock cleanly between them. The maps differ. The [CDC](https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/yellow-fever.html) says yellow fever occurs in Sub-Saharan Africa and tropical South America; the WHO counts 27 African and 13 Latin American countries as high-risk for outbreaks. The CDC's malaria list covers large areas of Africa, Latin America, and parts of the Caribbean, the South Pacific and Asia; the CDC cites WHO's count of 83 malaria-endemic countries. The defenses follow. The [CDC](https://www.cdc.gov/yellow-fever/prevention/index.html) says the best way to prevent yellow fever is to prevent mosquito bites and get vaccinated before traveling, if vaccination is recommended for you; the WHO says a single dose provides lifelong immunity, no booster needed. Malaria runs on a different defense: the CDC says there is no vaccine for malaria currently available in the U.S. The CDC's pointer: discuss the need for vaccination with your healthcare provider. ### Why does the night matter so much with malaria? Because the vector is nocturnal. The Yellow Book: "Malaria transmission occurs primarily between dusk and dawn because of the nocturnal feeding habits of *Anopheles* mosquitoes." CDC's table of peak biting periods lists *Anopheles* as night and evening, against dawn and dusk for the *Aedes* species behind [dengue](https://longsleeve.com/blog/dengue-travel), and late evening for *Culex quinquefasciatus*, a [West Nile](https://longsleeve.com/blog/west-nile-virus) vector. Two qualifiers. CDC says biting activity for *Anopheles* varies with the species, and only that peak activity "tends to be during the night or evening hours." It also warns that regional variations and overlap in feeding times mean travelers "need to be cautious about mosquito bites at all times of day and night in regions where mosquito-borne diseases are a risk." Night is where the odds concentrate. It does not make daytime free. [CDC](https://www.cdc.gov/malaria/hcp/risk-assessment/index.html)'s risk assessment guidance tells clinicians that even in low-risk situations, "it only takes one bite from an infective female *Anopheles* mosquito to transmit malaria," and to ask whether a traveler will be outdoors in the evenings for dining or entertainment. ### What are the CDC's mosquito avoidance layers? CDC lists them as a stack to run together. Use an EPA-registered insect repellent. Wear loose-fitting, long-sleeved shirts, pants, and socks. Treat clothing and gear such as boots and tents with 0.5% permethrin, or buy pre-treated gear, and never apply permethrin to skin. Keep windows and doors screened, and repair broken screens. Sleep in a well-screened or air-conditioned room, or under a permethrin-treated bed net. [CDC](https://wwwnc.cdc.gov/travel/page/avoid-bug-bites) names six active ingredients found in EPA-registered products: DEET, picaridin (known as KBR 3023 and icaridin outside the US), IR3535, oil of lemon eucalyptus, para-menthane-diol, and 2-undecanone. The WHO's version: use mosquito repellents containing DEET, IR3535, or icaridin after dusk. The EPA is explicit about what a government list is not: "EPA and the U.S. Government do not endorse any product or service." The bed net has a spec, and CDC publishes it: compact, white, rectangular, 156 holes per square inch, long enough to tuck under the mattress. CDC says to buy one before traveling overseas, and that permethrin-treated nets provide more protection than untreated nets. More in [permethrin-treated clothing](https://longsleeve.com/blog/permethrin-clothing) and [mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). ### Why does the choice of prophylaxis depend on destination and health history? CDC states that recommended drugs for each country "are listed in alphabetical order and have comparable efficacy in that country." CDC tells the traveler and clinician to weigh drug resistance at the destination, length of travel, the patient's other medical conditions, allergy history, other medications already being taken so interactions can be assessed, side effects, and cost. Resistance draws the first line. Chloroquine-resistant *P. falciparum* is found in all parts of the world (Africa, Asia, South America) except the Caribbean and Central American countries west of the Panama Canal, and chloroquine cannot be used where that resistance exists. Mefloquine-resistant *P. falciparum* has been confirmed in parts of Southeast Asia, and CDC says mefloquine cannot be used in areas with mefloquine resistance. Then your own history narrows it further. Per CDC's prescribing table, atovaquone-proguanil cannot be taken by people with severe renal impairment, or by women pregnant or breastfeeding a child under 5 kg. Doxycycline cannot be used by pregnant women or children under 8. Mefloquine cannot be used in patients with certain psychiatric conditions or a seizure disorder. Primaquine and tafenoquine cannot be used in patients with G6PD deficiency, and CDC says quantitative G6PD testing must be done before either is prescribed. Timing is the third variable, which is why last-minute trips change the answer. CDC's table starts atovaquone-proguanil, doxycycline, and primaquine 1 to 2 days before travel, tafenoquine 3 days before, chloroquine and mefloquine 1 to 2 weeks before. The tail differs too: 7 days after leaving for atovaquone-proguanil and primaquine, one week for tafenoquine, 4 weeks for chloroquine, doxycycline, and mefloquine. CDC and WHO differ here. WHO gives one blanket instruction, that all prophylactic drugs "should be continued for 4 weeks after the last possible exposure to infection since parasites may still emerge from the liver during this period," while CDC's table sets a different tail for each drug. Follow the schedule your prescriber gives you. Three more things from CDC. Get all your medications in the US before traveling, because counterfeit and substandard drugs are sold in some countries where malaria spreads. There is no vaccine for malaria currently available in the US. And no antimalarial drug is 100% protective, which is why the mosquito layers stay on. ### How do you look up malaria prophylaxis for a specific country? Open the CDC Yellow Book chapter [Yellow Fever Vaccine and Malaria Prevention Information, by Country](https://www.cdc.gov/yellow-book/hcp/preparing-international-travelers/yellow-fever-vaccine-and-malaria-prevention-information-by-country.html), 2026 edition, and read your destination's row. The CDC's summary of the chapter: country-specific yellow fever vaccine entry requirements and CDC recommendations, plus malaria transmission information and prevention recommendations. The drugs in the row are the ones the CDC recommends for that country, in the alphabetical order described above, so read the row as a list rather than a ranking. The worked example is India, from [CDC's Travelers' Health page for India](https://wwwnc.cdc.gov/travel/destinations/traveler/none/india). The CDC recommends that travelers going to certain areas of India take prescription medicine to prevent malaria, started multiple days before the trip depending on the medicine and continued during and after it. Transmission areas: throughout the country, including Mumbai and New Delhi, with none above 2,000 m (6,500 ft) in the areas the CDC lists by state. Drug resistance: chloroquine. Species: *P. falciparum* 60%, *P. vivax* 40%. Recommended chemoprophylaxis, in the CDC's alphabetical listing: atovaquone-proguanil, doxycycline, mefloquine, tafenoquine. Yellow fever, same page: vaccine not recommended, not required for direct travel from the United States, required for travelers 9 months and older arriving from countries India regards as having yellow fever risk. The row is where the conversation starts. The CDC says to use these recommendations alongside an individual risk assessment of itinerary, cities, accommodations, season, style of travel and conditions such as pregnancy; depending on the level of risk, it might be appropriate to recommend no specific interventions, mosquito avoidance only, or mosquito avoidance plus chemoprophylaxis. Mosquito avoidance, in the CDC's definition, means topical repellent, an insecticide-treated bed net, and long pants, socks and a long-sleeve shirt: see the [permethrin and picaridin system](https://longsleeve.com/blog/permethrin-picaridin-system). Check the CDC site for updates, because the CDC says transmission can change rapidly and from year to year. Then take the row, your itinerary, activities, accommodations and medical history to a healthcare provider, which the CDC says is how you learn your risk and whether you need medication. ### Which travelers are most often caught out? The Yellow Book names long-term travelers and expatriates, and travelers visiting friends and relatives, as the categories at greatest risk. In the surveillance data the chapter cites, 76% of U.S. civilians with malaria who reported a reason for travel were visiting friends and relatives. CDC traces that to an assumption rather than to where people go: "VFR travelers may erroneously consider themselves immune to malaria because they grew up in a malaria-endemic country. The partial immunity acquired through continuous exposure to malaria is lost quickly, and VFR travelers should be considered to have the same risk of malaria as other nonimmune travelers." Style of travel matters too. CDC notes that short-term business travelers in air-conditioned hotels may be at lower risk than backpackers, and that travelers going to rural areas or staying without screens or air conditioning are at greater risk. On pregnancy, CDC is direct: malaria infection in pregnant women can be more severe than in nonpregnant women, so women who are pregnant or likely to become pregnant should be advised to avoid travel to areas with malaria transmission if possible. ### What are the symptoms, and how fast do you need to move? The Yellow Book describes malaria as characterized by fever and influenza-like symptoms, including chills, headache, muscle aches, and malaise, plus nausea, vomiting, and diarrhea. Symptoms can occur intermittently. Severe disease can involve acute kidney injury, mental confusion, severe anemia, seizures, coma, and death. The clock is unusual. [CDC](https://www.cdc.gov/malaria/symptoms/index.html) says the incubation period in most cases ranges from 7 to 30 days, that most people begin to feel ill as early as one week after infection or as late as a year or more, and that some species can remain dormant in the liver for months or years. That is why CDC tells travelers to seek immediate medical attention for a fever or flu-like illness, whether abroad or for up to one year after returning home, and to tell the provider the travel history. The WHO: left untreated, *P. falciparum* malaria can progress to severe illness and death within 24 hours. The Yellow Book calls suspected or confirmed malaria, especially *P. falciparum*, "a medical emergency requiring urgent intervention because clinical deterioration, including death, can occur rapidly and unpredictably." The Yellow Book says travelers with symptoms should seek the best available medical services as soon as possible, even if still traveling, and continue chemoprophylaxis until they have a definitive diagnosis. CDC says interventions are not 100% effective, "so all febrile persons returning from malaria-endemic areas should be tested for malaria even if they took chemoprophylaxis." Blood smear microscopy remains the most important diagnostic method, and CDC says results should be available as soon as possible, within 24 hours of the patient's presentation. Every decision about testing, medication, and treatment belongs to a clinician who knows your itinerary and your history. ### Where Longsleeve fits Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with [nine disclosed ingredients](https://longsleeve.com/ingredients). ### Common questions **Do I still need repellent and a bed net if I am taking antimalarial pills?** Yes. CDC says no antimalarial drug is 100% protective, so travelers must combine chemoprophylaxis with mosquito avoidance and personal protective measures, including long sleeves, long pants, and sleeping in a mosquito-free setting under an insecticide-treated net. **How long after a trip can malaria show up?** Longer than most people expect. CDC says the incubation period in most cases ranges from 7 to 30 days, but people can begin to feel ill as late as a year or more, because some species stay dormant in the liver. CDC tells travelers to seek immediate medical attention for a fever for up to one year after returning home, and to mention the travel history. **Which antimalarial is the best one?** CDC does not frame it that way. Recommended drugs for each country are listed in alphabetical order and have comparable efficacy in that country. The choice comes down to resistance at your destination, trip length, your other conditions and medications, side effects, and cost. CDC tells travelers to work that out with a healthcare provider, using a detailed itinerary, your activities, your accommodations, and your medical history. **Is the yellow fever vaccine also protection against malaria?** The yellow fever vaccine covers yellow fever, which the WHO calls a vaccine-preventable disease; for malaria, the CDC says there is no vaccine currently available in the U.S., and prevention means antimalarial medication plus preventing mosquito bites. They are different diseases: the CDC says yellow fever virus is a Flavivirus and malaria is Plasmodium species carried by Anopheles mosquitoes. The CDC says to discuss the need for yellow fever vaccination with your healthcare provider. **Does DEET or picaridin prevent malaria?** The CDC's malaria prevention page lists DEET, picaridin (known as KBR 3023 and icaridin outside the US) and IR3535 among the EPA-registered insect repellent active ingredients, and puts repellent in the bite-avoidance layer that it tells travelers to run alongside chemoprophylaxis, not in place of it. The CDC adds that prevention strategies can be very effective, but none will protect 100% of the time. ### Related reading - [Dengue and travel](https://longsleeve.com/blog/dengue-travel). The daytime-biting counterpart, and why one trip can need two different habits. - [Permethrin-treated clothing](https://longsleeve.com/blog/permethrin-clothing). What 0.5% permethrin does on fabric, and why it never goes on skin. - [Why mosquitoes bite some people more](https://longsleeve.com/blog/why-mosquitoes-bite-some-people). What actually draws them, and what does not. - [Our field guide to biting insects](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. CDC, About Malaria. [https://www.cdc.gov/malaria/about/index.html](https://www.cdc.gov/malaria/about/index.html) 1. CDC, Preventing Malaria While Traveling. [https://www.cdc.gov/malaria/prevention/index.html](https://www.cdc.gov/malaria/prevention/index.html) 1. CDC, Symptoms of Malaria. [https://www.cdc.gov/malaria/symptoms/index.html](https://www.cdc.gov/malaria/symptoms/index.html) 1. CDC, Where Malaria Occurs. [https://www.cdc.gov/malaria/data-research/index.html](https://www.cdc.gov/malaria/data-research/index.html) 1. CDC, Choosing a Drug to Prevent Malaria. [https://www.cdc.gov/malaria/hcp/drug-malaria/index.html](https://www.cdc.gov/malaria/hcp/drug-malaria/index.html) 1. CDC, Malaria Risk Assessment for Travelers. [https://www.cdc.gov/malaria/hcp/risk-assessment/index.html](https://www.cdc.gov/malaria/hcp/risk-assessment/index.html) 1. CDC Yellow Book, Malaria. [https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/malaria.html](https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/malaria.html) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. CDC Travelers' Health, Avoid Bug Bites. [https://wwwnc.cdc.gov/travel/page/avoid-bug-bites](https://wwwnc.cdc.gov/travel/page/avoid-bug-bites) 1. WHO, Malaria fact sheet. [https://www.who.int/news-room/fact-sheets/detail/malaria](https://www.who.int/news-room/fact-sheets/detail/malaria) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. CDC Yellow Book 2026, Yellow Fever, April 23, 2025. [https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/yellow-fever.html](https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/yellow-fever.html) 1. World Health Organization, Yellow fever fact sheet, 20 October 2025. [https://www.who.int/news-room/fact-sheets/detail/yellow-fever](https://www.who.int/news-room/fact-sheets/detail/yellow-fever) 1. CDC, Preventing Yellow Fever, May 15, 2024. [https://www.cdc.gov/yellow-fever/prevention/index.html](https://www.cdc.gov/yellow-fever/prevention/index.html) 1. CDC, Yellow Fever: Causes and How It Spreads, July 15, 2026. [https://www.cdc.gov/yellow-fever/causes-and-spread/index.html](https://www.cdc.gov/yellow-fever/causes-and-spread/index.html) Last reviewed 2026-08-16 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Mosquito Bite Treatment: Itch, Swelling, and Infection Signs URL: https://longsleeve.com/blog/mosquito-bite-treatment > CDC mosquito bite treatment steps: wash, ice for 10 minutes, use anti-itch or antihistamine cream as directed, avoid scratching, and watch for infection signs. Source: https://longsleeve.com/blog/mosquito-bite-treatment By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 6, 2026 · Updated August 16, 2026 **Short answer:** For a normal mosquito bite, CDC guidance says to wash the bite and surrounding skin with soap and water, apply an ice pack for 10 minutes to reduce swelling and itching, and use an over-the-counter anti-itch or antihistamine cream as directed. Do not scratch. See a healthcare provider if symptoms worsen or the bite looks infected. That is the whole treatment for a normal bite. The harder part is telling a harmless reaction from an infection. ### Why does a mosquito bite itch? The CDC describes the mechanics plainly. When a mosquito bites you, it pierces the skin using a special mouthpart called a proboscis to suck up blood, and as it feeds it injects saliva into your skin. Your body reacts to the saliva, and that reaction is the bump and the itching. A 2022 review in Frontiers in Immunology describes histamine as a key player, either histamine present in mosquito saliva itself or histamine released when mast cells are activated by IgE primed against saliva proteins. Histamine binds to receptors on nerve endings and drives local vasodilation and edema, which is what forms the wheal. Other salivary components, including tryptase and leukotrienes, may induce non-histaminergic itch. The reaction runs in phases. That review describes an immediate reaction, a round wheal 2 to 10 mm across with redness peaking in 20 to 30 minutes, then a delayed reaction of itchy papules the same size that peak in 24 to 36 hours and fade over several days. The [CDC](https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html) lists what you may see: a puffy reddish bump minutes after the bite, a hard, itchy, reddish-brown bump a day or so later, small blisters instead of hard bumps, or dark spots that look like bruises. People react differently, and the CDC says so outright. Some have only a mild reaction, others react more strongly with a large area of swelling, soreness, and redness. ### What does the CDC recommend for treating a mosquito bite? 1. **Wash the bite and surrounding area with soap and water.** 1. **Apply an ice pack for 10 minutes** to reduce swelling and itching. Reapply as needed. 1. **Apply a mixture of baking soda and water,** which the CDC says can help reduce the itch response. Mix 1 tablespoon of baking soda with just enough water to create a paste, apply it to the bite, wait 10 minutes, then wash it off. 1. **Use an over-the-counter anti-itch or antihistamine cream** to help relieve itching, following the product label directions. The cold is doing real work. The Frontiers review notes that cooling reduces itch through TRPM8, an ion channel in peripheral nerve endings, inhibiting both histaminergic and non-histaminergic itch pathways. The American Academy of Pediatrics adds options in its mosquito bite guidance on HealthyChildren.org: 1% hydrocortisone cream three times a day until the itch is gone, ice in a wet washcloth for 20 minutes as a fallback, and firm, steady pressure on the bite for 10 seconds with a fingernail or pen cap. For severe itching it mentions an oral allergy medicine, with age limits on the page. ### Why does scratching make it worse? The CDC's instruction is one line: do not scratch bites, they can become infected. The AAP explains the mechanism. Infections of mosquito bites are not common, and they most often occur in bites that have been scratched or picked at, usually starting with an infected sore or scab. For kids, the AAP advice is to cut the fingernails short and help the child not to scratch. The Frontiers review lists the consequences of scratching as scarring, hyperpigmentation, and superinfection. ### How can you tell if a mosquito bite is infected? The CDC gives three markers: an infected bite may appear red, feel warm, or a red streak may spread outward from the bite. See a healthcare provider if symptoms worsen. The trap is that a large, red, angry-looking bite is usually not an infection. The [AAP](https://www.healthychildren.org/English/tips-tools/symptom-checker/Pages/symptomviewer.aspx?symptom=Mosquito+Bite) describes large local reactions as very common in young children, with redness reaching 2 to 4 inches (5 to 10 cm) that starts right after the bite and may keep getting larger for 2 to 3 days. Per the AAP that is still normal: a harmless local allergic reaction to mosquito saliva, not a sign of infection. The feature that separates them is pain, because infections of mosquito bites are painful to touch. Timing separates them too. The AAP states that any redness starting in the first 24 hours is always a reaction to the bite. The infections the AAP names are impetigo, which gives sores, soft scabs, and pus; cellulitis, where redness spreads out from the bite and the red area hurts to touch; and lymphangitis, a red line running up the arm or leg, which the AAP calls more serious because the infection can reach the bloodstream. One lookalike is worth naming. The Frontiers review describes Skeeter syndrome, a large local inflammatory reaction of redness, warmth, swelling, and itching that can come with fever and swollen lymph nodes. It mimics cellulitis, and the review says the difference is duration: Skeeter syndrome occurs within hours of a bite and resolves in 3 to 10 days. ### What does normal healing look like? The AAP's expectations for an ordinary bite: most itch for 3 or 4 days, any pinkness or redness lasts 3 or 4 days, and swelling may last 7 days. Bites on the upper face can cause severe swelling around the eye, which the AAP says does not hurt vision and is harmless. ### How do you avoid the next one? The CDC's mosquito prevention guidance starts with repellent. Use EPA-registered insect repellents with one of six active ingredients: DEET, picaridin (KBR 3023 or icaridin outside the United States), IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone. Look for an EPA registration number (EPA Reg. No.) on the label, which the [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html) says means the company provided EPA with technical information on the effectiveness of the product. Follow the label instructions, reapply as directed, and if you use sunscreen, apply it first. For children the CDC adds: no OLE or PMD on children under 3 years old, no repellent on a child's hands, eyes, mouth, cuts, or irritated skin, and apply it to your own hands first before a child's face. Past repellent, the CDC recommends loose-fitting long sleeves and pants, [permethrin-treated clothing and gear](https://longsleeve.com/blog/permethrin-clothing) (never on skin), window and door screens, and emptying anything that holds water once a week. If the thing that bit you is still attached, that is a different procedure. See [how to remove a tick](https://longsleeve.com/blog/tick-removal) and [Lyme disease prevention](https://longsleeve.com/blog/lyme-disease-prevention). ### When should you see a doctor about a mosquito bite? The CDC's baseline is to see a healthcare provider if symptoms worsen. The AAP's guidance is more granular. - **Call 911** if a life-threatening allergic reaction is suspected, which the AAP describes as sudden onset of trouble breathing or swallowing, or if the person cannot be woken up. - **Go to the ER** for someone hard to wake up, confused, barely able to walk, or with a stiff neck. - **Call a doctor or seek care now** for a spreading red area or streak with fever, or if the person looks or acts very sick. - **Contact a doctor within 24 hours** for painful spreading redness starting more than 48 hours after the bite, redness still growing more than 72 hours after, or an unexplained fever after recent travel outside the country to a high-risk area. - **Contact a doctor during office hours** for an infected-looking scab no better with antibiotic ointment, or severe itching no better after 24 hours of steroid cream. Fever after mosquito exposure is its own category, because mosquitoes spread germs through bites that can make you sick. For West Nile virus, the [CDC](https://www.cdc.gov/west-nile-virus/signs-symptoms/index.html) says symptoms usually start 2 to 6 days after being bitten by an infected mosquito but can start anywhere from 2 to 14 days, that most people (80%) infected develop no symptoms, and that about 20% develop flu-like symptoms such as fever with headache, body aches, joint pains, vomiting, diarrhea, or rash. Seek immediate medical attention, the CDC says, for high fever, neck stiffness, muscle weakness, confusion, or tremors. If you have traveled, dengue belongs on the list. The CDC says the most common symptom is fever with aches and pains, nausea or vomiting, or rash, and to see a provider if you have those symptoms and have recently been in an area with risk of dengue. Severe dengue is a medical emergency: go immediately to a clinic or emergency room for belly pain or tenderness, repeated vomiting, bleeding from the nose or gums, blood in vomit or stool, or extreme tiredness or restlessness. ### What does a severe reaction look like? The CDC says severe reactions can occur in children, in adults bitten by mosquito species they have not been exposed to previously, and in people with immune system disorders. The more severe reactions it lists are a large area of swelling and redness, low-grade fever, hives, and swollen lymph nodes. True anaphylaxis from a mosquito bite is extraordinarily rare. The Frontiers review notes that IgE-mediated reactions to mosquito saliva range from large local reactions to very rare life-threatening anaphylaxis presenting as presyncope, hypotension, and syncope, and that fewer than thirty anaphylactic reactions to mosquitoes have been reported worldwide. Rare is not never, and the AAP threshold stands: sudden trouble breathing or swallowing means 911. ### About Longsleeve Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients. None of this replaces medical advice. If a bite is getting worse instead of better, or you run a fever after being bitten, call your doctor and mention the bite. ### Common questions **Is a huge swollen mosquito bite an allergic reaction?** Usually not the dangerous kind. The AAP says a large hive at the bite does not mean your child has an allergy, and calls large local reactions with 2 to 4 inches of redness a harmless local allergic reaction to mosquito saliva, not a sign of infection. **Does baking soda actually help?** The CDC includes it and says the mixture can help reduce the itch response: 1 tablespoon of baking soda with just enough water to make a paste, applied for 10 minutes, then washed off. The Frontiers review lists sodium bicarbonate among options with a paucity of supporting evidence for specific alleviation of mosquito bite symptoms, so treat it as cheap to try rather than proven. **When does a bite stop being normal?** Per the AAP, call a doctor if the bite looks infected, meaning the redness gets larger after 48 hours or there is pus discharge, or if the bite becomes very painful. ### Related reading - [Insect Repellent and Children](https://longsleeve.com/blog/mosquito-repellent-for-kids). What the CDC and AAP actually say about repellent on kids. - [Why Mosquitoes Bite Some People More](https://longsleeve.com/blog/why-mosquitoes-bite-some-people). What the evidence supports, and what it refutes. - [Standing Water and Mosquito Control](https://longsleeve.com/blog/standing-water-mosquito-control). The only home control with real evidence behind it. - [The species almanac](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. - [Dengue and Travel](https://longsleeve.com/blog/dengue-travel). When a bite abroad is worth taking seriously. More Longsleeve in your Google feed: ### Sources 1. CDC, About Mosquito Bites. [https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html](https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC, Symptoms of West Nile. [https://www.cdc.gov/west-nile-virus/signs-symptoms/index.html](https://www.cdc.gov/west-nile-virus/signs-symptoms/index.html) 1. CDC, Symptoms of Dengue and Testing. [https://www.cdc.gov/dengue/signs-symptoms/index.html](https://www.cdc.gov/dengue/signs-symptoms/index.html) 1. American Academy of Pediatrics, HealthyChildren.org Symptom Checker: Mosquito Bite. [https://www.healthychildren.org/English/tips-tools/symptom-checker/Pages/symptomviewer.aspx?symptom=Mosquito+Bite](https://www.healthychildren.org/English/tips-tools/symptom-checker/Pages/symptomviewer.aspx?symptom=Mosquito+Bite) 1. Vander Does A, Labib A, Yosipovitch G. Update on mosquito bite reaction: Itch and hypersensitivity, pathophysiology, prevention, and treatment. *Frontiers in Immunology*, 2022;13:1024559. [https://pmc.ncbi.nlm.nih.gov/articles/PMC9532860/](https://pmc.ncbi.nlm.nih.gov/articles/PMC9532860/) Last reviewed 2026-08-06 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Mosquito Repellent Candles, Torches and Coils: What Works URL: https://longsleeve.com/blog/mosquito-repellent-candles > Studies found relatively small reductions in bites from citronella candles. How to read the label, where to put candles and coils, and what goes on skin. Source: https://longsleeve.com/blog/mosquito-repellent-candles By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 31, 2026 · Updated October 2, 2026 **Short answer:** For citronella candles, a little, and less with distance in the one study that measured it. In a field study, 3% citronella candles reduced bites from Aedes mosquitoes by 42.3% overall, and in an outdoor study, candle repellency measured at 1 meter dropped significantly when the distance increased to 2 and 3 meters. The candle, torch fuel and coil labels we read restrict them to outdoor use, and the CDC Yellow Book tells travelers to supplement spatial repellents, which it says include mosquito coils, with an EPA-registered repellent on skin or clothing. ### Do mosquito repellent candles actually work? For citronella candles, somewhat in four of the five tests below, and not at all in one. In a field study in a woodlot in Guelph, Ontario, Lindsay and colleagues tested 3% citronella candles against bites of Aedes mosquitoes: subjects received on average 6.2 bites per 5 minutes at positions with citronella candles, 8.2 with plain candles and 10.8 with no candles, and the authors described the overall reduction from the citronella candles as only 42.3%. Other tests used different oils, settings and measures, and got different numbers. In human landing assays in a high biting pressure environment in Israel, Muller and colleagues (2008) measured a repellency rate of 29.0% for 5% citronella candles and 85.4% for 5% geraniol candles. Outdoors, at a distance of 1.0 meter, a second 2008 paper by Muller and colleagues found citronella candles reduced the number of female mosquitoes caught in traps by 35.4%. In a 2009 paper, Muller and colleagues reported that indoors the repellency rate of citronella candles was only 14%, while citronella diffusers reached 68%. And in a wind tunnel test of Aedes aegypti by Rodriguez and colleagues, the citronella candle had no effect. The [University of Wisconsin-Madison](https://mosquitosite.russell.wisc.edu/preventing-mosquito-bites/area-repellants/)'s entomology department sums up the tests of candles and other devices emitting citronella as suggesting relatively small reductions in the number of biting mosquitoes. The plant-oil evidence is covered in full in our post on [citronella and plant-based repellents](https://longsleeve.com/blog/citronella-and-plant-repellents). ### What is in a mosquito candle, and is it EPA-registered? It depends on the product: some are registered with EPA and some are sold under an exemption. [EPA](https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-021901_01-Nov-99.pdf)'s fact sheet on oil of citronella says it is found in many familiar insect repellent products, candles among them, and that these products vary in efficacy. One registered citronella candle, EPA Reg. No. 90266-1, lists oil of citronella at 3% as its active ingredient. The same fact sheet says some citronella products are exempt from the usual regulation, and that registration is required for those that do not meet the criteria for exemption. The exemption is EPA's minimum risk category. [EPA](https://www.epa.gov/minimum-risk-pesticides) says it has determined that certain minimum risk pesticides pose little to no risk to human health or the environment, and has exempted them from the requirement that they be registered. A product has to meet six conditions to qualify. EPA publishes a list of active ingredients that can be used in products exempt under the minimum risk regulations, and citronella oil and geraniol are on it. All of its ingredients, active and inert, must be listed on the label, with the active ingredients shown by percentage by weight. Its label claim may only be for the pest as a pest, and not as a disease vector. EPA adds that states may require registration under state laws. What the exemption means for a shopper is in EPA's own words: EPA does not review exempted products, and on its page about skin-applied repellents, EPA says products made from the active ingredients in unregistered repellents have not been evaluated for effectiveness. On the shelf, the tell is the number. EPA says you will see an EPA Registration Number on the product label of any EPA-registered product, and it says statements that could suggest federal review are a problem on an exempt product: because EPA does not review exempted products, such a statement is misleading, and consumers could mistakenly assume that EPA or another federal agency has reviewed or accepted the product. [EPA](https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents) also says it is not simple to determine the status of products in many cases. Our guide to [natural bug repellents](https://longsleeve.com/blog/natural-repellents) covers the registered and exempt plant oils. ### What can you burn outside: candles, torches or coils? All three exist as labeled products, and still air matters for all of them. The [American Mosquito Control Association](https://www.mosquito.org/repellents/) says oil of citronella is the active ingredient in many of the candles, torches, or coils that can be burned to produce a vapor or smoke that repels mosquitoes, and that these are only useful outdoors when the wind is not blowing. Torches burn a fuel: one registered citronella torch fuel, EPA Reg. No. 33025-6, lists oil of citronella at 3%, and its label says for outdoor use only. Coils are a different kind of product. The [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) Yellow Book says spatial repellents, including mosquito coils, contain active ingredients such as metofluthrin and allethrin, and one registered coil, EPA Reg. No. 4822-602, lists metofluthrin at 0.02%. The American Mosquito Control Association says mosquito coils use a synthetic pyrethroid insecticide that has repellent properties, and are most effective in situations of little wind. One study supports coils. In field trials in Illinois in June 1998, Jensen and colleagues found that mosquito smoke coils containing a pyrethroid significantly reduced mosquito landing rates relative to untreated controls. The University of Wisconsin-Madison says studies indicate that area repellents emitting small doses of allethrin can reduce the number of biting mosquitoes, that many lanterns, coils, and candles reduce mosquito bites, and that some devices use repellents to protect a small area like a patio. Whatever you burn, use a product labeled for that purpose and follow its label. Other patio gadgets have their own posts: [bug zappers](https://longsleeve.com/blog/bug-zappers) and [ultrasonic repellers](https://longsleeve.com/blog/ultrasonic-repellers). ### Where should a candle or coil go, and how far does it reach? Close to the people, outdoors, in still air. The distance data are short. In the second 2008 paper by Muller and colleagues, an outdoor test, candles were measured at a distance of 1.0 meter, and the repellency dropped significantly when the distance increased to 2 and 3 meters. The University of Wisconsin-Madison says that in an outdoor setting, geraniol candles gave moderate protection to volunteers seated within a 1 meter distance from the candles. Diffusers are a different device: in the 2009 paper by Muller and colleagues, citronella diffusers placed outdoors 6 meters from mosquito traps repelled female mosquitoes by 22%. Labels give placement in their own terms, and each one applies to its own product. The label of the registered citronella candle, EPA Reg. No. 90266-1, says to use more than one candle in still air, with multiple candles spaced 18 inches apart around the perimeter of the outdoor space, within 3 feet of where people will gather. The label of the registered coil, EPA Reg. No. 4822-602, says to place the coils outdoors in semi-confined areas such as porches, patios and yards where there is minimal breeze, not to use them in wind, and to use one coil for each 10 by 10 foot area. The torch fuel label's optional language says not to use it in windy conditions. For the rest of the patio plan, see [how to keep mosquitoes away from your patio](https://longsleeve.com/blog/how-to-keep-mosquitoes-away-from-patio-dinner). ### Is the smoke a problem, and how do you avoid a fire? The CDC's advice is to avoid breathing the smoke directly. The CDC Yellow Book says to use spatial repellents with caution and to avoid direct inhalation of spray or smoke. The registered coil's label says not to use it indoors and not to touch the lit end of the coil. The smoke research gathered here is about coils. Liu and colleagues characterized the emissions from four common brands of mosquito coils from China and two common brands from Malaysia, and when they applied the measured emission rates to predict indoor concentrations under realistic room conditions, they found pollutant concentrations could substantially exceed health-based air quality standards or guidelines. That finding covers those coil brands under modeled indoor conditions. The sources gathered here do not address smoke from citronella candles. Fire safety is label territory too. The registered candle's label says to place the candle on a heat-resistant surface away from anything flammable and away from children and pets, and that the container and wax will be hot when the candle is lit. The torch fuel label's optional language says not to place a torch under covered shelter or umbrellas, or near pedestrian traffic or combustibles. The U.S. Fire Administration's candle rules: keep candles at least 12 inches away from anything that burns, blow out candles when you leave a room or home or when you go to bed, and use stable holders placed where they cannot be knocked down easily. ### Can a candle replace repellent on your skin? None of the sources here treats a candle as a substitute. In the Illinois field trials, which included citronella candles and mosquito smoke coils, Jensen and colleagues reported that the DEET topical repellent had a consistently lower landing rate than all the nontopically applied products tested. The American Mosquito Control Association says citronella candles, torches and coils are less effective than repellents applied to the body or permethrin applied to clothing. The CDC Yellow Book says spatial repellents have not yet been adequately evaluated in peer-reviewed studies for efficacy in preventing vector-borne diseases, and that travelers should supplement them with an EPA-registered repellent on skin or clothing. The [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html)'s bite-prevention steps include using EPA-registered insect repellents, wearing loose-fitting, long-sleeved shirts and pants, and wearing clothing and gear treated with permethrin. It says an EPA registration number on a repellent's label means the company provided EPA with technical information on the effectiveness of the product. You can compare registered skin repellents by their label data in [The Repellent Index](https://longsleeve.com/repellent-index). ### About Longsleeve Longsleeve is an EPA-registered insect repellent lotion with 20% picaridin (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours, is fragrance free, and goes on exposed skin as the label directs. ### Common questions **Are citronella candles EPA-registered?** Some are. EPA's records list a citronella candle under EPA Reg. No. 90266-1, with oil of citronella at 3%. EPA's citronella fact sheet says some citronella products are exempt from the usual regulation, and EPA's minimum risk rules say a product that meets all six conditions does not need to be registered with EPA. EPA says any EPA-registered product shows an EPA Registration Number on its label. **Can you burn a mosquito candle or coil indoors?** The labels we read say no. One registered citronella candle (EPA Reg. No. 90266-1) is labeled for outdoor use only, and one registered coil's label (EPA Reg. No. 4822-602) says do not use indoors. The CDC Yellow Book also says to avoid direct inhalation of spray or smoke from spatial repellents. **How many citronella candles do I need for a patio?** One registered candle's label says to use more than one candle in still air, with multiple candles spaced 18 inches apart around the perimeter of the outdoor space, within 3 feet of where people will gather. That is one product's label, so follow the label on yours. **Do mosquito coils work?** In field trials in Illinois in June 1998, mosquito smoke coils containing a pyrethroid significantly reduced mosquito landing rates relative to untreated controls, though the DEET topical repellent had a consistently lower landing rate than all the nontopically applied products tested. The American Mosquito Control Association says coils are most effective in situations of little wind. **Do mosquito candles work in the wind?** The sources say wind works against them. The American Mosquito Control Association says citronella candles, torches and coils are only useful outdoors when the wind is not blowing. One registered candle's label calls for still air, and one registered coil's label says not to use it in wind. **Are citronella candles toxic to dogs or kids?** The label of one registered citronella candle, EPA Reg. No. 90266-1, says "Hazardous to humans and domestic animals. Harmful if swallowed," and says to place the candle away from children and pets. EPA's 1999 citronella fact sheet says that when used according to the label, citronella products are not expected to cause harm to humans, pets or the environment. **Can a citronella candle replace bug spray?** The CDC Yellow Book tells travelers to supplement spatial repellents, which it says include mosquito coils, with an EPA-registered repellent on skin or clothing. The CDC says that to protect yourself against germs spread by mosquitoes, it and EPA recommend using an EPA-registered insect repellent. ### Related reading - [Do Citronella Candles Work?](https://longsleeve.com/blog/citronella-and-plant-repellents) Evidence on plant-based repellents. - [How to Keep Mosquitoes Away From Your Patio](https://longsleeve.com/blog/how-to-keep-mosquitoes-away-from-patio-dinner). Water, fans, sprays and what goes on skin. - [Natural Bug Repellents](https://longsleeve.com/blog/natural-repellents). EPA registration, plant oils, OLE, PMD, and evidence. - [Do Bug Zappers Work on Mosquitoes?](https://longsleeve.com/blog/bug-zappers) What field studies found. - [Do Ultrasonic Mosquito Repellers Work?](https://longsleeve.com/blog/ultrasonic-repellers) Cochrane review and FTC history. ### Sources 1. EPA, Minimum Risk Pesticides. [https://www.epa.gov/minimum-risk-pesticides](https://www.epa.gov/minimum-risk-pesticides) 1. EPA, Conditions for Minimum Risk Pesticides. [https://www.epa.gov/minimum-risk-pesticides/conditions-minimum-risk-pesticides](https://www.epa.gov/minimum-risk-pesticides/conditions-minimum-risk-pesticides) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. Lindsay et al., J Am Mosq Control Assoc 1996;12(2 Pt 1):293-4 (PubMed abstract, PMID 8827606). [https://pubmed.ncbi.nlm.nih.gov/8827606/](https://pubmed.ncbi.nlm.nih.gov/8827606/) 1. Muller et al., J Am Mosq Control Assoc 2008;24(1):150-3, 'Indoor protection against mosquito and sand fly bites' (PMID 18437831). [https://pubmed.ncbi.nlm.nih.gov/18437831/](https://pubmed.ncbi.nlm.nih.gov/18437831/) 1. Muller et al., J Am Mosq Control Assoc 2008;24(1):154-60 (PMID 18437832). [https://pubmed.ncbi.nlm.nih.gov/18437832/](https://pubmed.ncbi.nlm.nih.gov/18437832/) 1. Muller et al., J Vector Ecol 2009;34(1):2-8 (PMID 20836800). [https://pubmed.ncbi.nlm.nih.gov/20836800/](https://pubmed.ncbi.nlm.nih.gov/20836800/) 1. Rodriguez et al., J Insect Sci 2017;17(1):24 (PMID 28423421). [https://pubmed.ncbi.nlm.nih.gov/28423421/](https://pubmed.ncbi.nlm.nih.gov/28423421/) 1. University of Wisconsin-Madison Department of Entomology, Area Repellents. [https://mosquitosite.russell.wisc.edu/preventing-mosquito-bites/area-repellants/](https://mosquitosite.russell.wisc.edu/preventing-mosquito-bites/area-repellants/) 1. EPA, Citronella (Oil of Citronella) (021901) Fact Sheet, issued 11/99. [https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-021901_01-Nov-99.pdf](https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-021901_01-Nov-99.pdf) 1. EPA Pesticide Product and Label System record, EPA Reg. No. 90266-1 (Patio Essentials Citronella Candle). [https://ordspub.epa.gov/ords/pesticides/cswu/ppls/90266-1](https://ordspub.epa.gov/ords/pesticides/cswu/ppls/90266-1) 1. EPA, Active Ingredients Allowed in Minimum Risk Pesticide Products (last updated August 10, 2026). [https://www.epa.gov/minimum-risk-pesticides/active-ingredients-allowed-minimum-risk-pesticide-products](https://www.epa.gov/minimum-risk-pesticides/active-ingredients-allowed-minimum-risk-pesticide-products) 1. EPA, Active Ingredients Eligible for Minimum Risk Pesticide Products (list, 2015-12-15). [https://www.epa.gov/sites/default/files/2015-12/documents/minrisk-active-ingredients-tolerances-2015-12-15.pdf](https://www.epa.gov/sites/default/files/2015-12/documents/minrisk-active-ingredients-tolerances-2015-12-15.pdf) 1. EPA, Regulation of Skin-Applied Repellents (last updated June 25, 2026). [https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents](https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents) 1. American Mosquito Control Association, Repellents. [https://www.mosquito.org/repellents/](https://www.mosquito.org/repellents/) 1. EPA Pesticide Product and Label System record, EPA Reg. No. 33025-6 (TIKI BiteFighter Clean Burn torch fuel). [https://ordspub.epa.gov/ords/pesticides/cswu/ppls/33025-6](https://ordspub.epa.gov/ords/pesticides/cswu/ppls/33025-6) 1. EPA-accepted label, TIKI BiteFighter Clean Burn torch fuel, EPA Reg. No. 33025-6, label dated 1/25/2022. [https://www3.epa.gov/pesticides/chem_search/ppls/033025-00006-20220207.pdf](https://www3.epa.gov/pesticides/chem_search/ppls/033025-00006-20220207.pdf) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods (web.archive.org snapshot 2026-09-19). [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. EPA Pesticide Product and Label System record, EPA Reg. No. 4822-602 (OFF! mosquito coil family). [https://ordspub.epa.gov/ords/pesticides/cswu/ppls/4822-602](https://ordspub.epa.gov/ords/pesticides/cswu/ppls/4822-602) 1. Jensen et al., J Am Mosq Control Assoc 2000;16(2):148-52 (PMID 10901639). [https://pubmed.ncbi.nlm.nih.gov/10901639/](https://pubmed.ncbi.nlm.nih.gov/10901639/) 1. EPA-accepted label, EPA Reg. No. 90266-1. [https://www3.epa.gov/pesticides/chem_search/ppls/090266-00001-20260918.pdf](https://www3.epa.gov/pesticides/chem_search/ppls/090266-00001-20260918.pdf) 1. EPA-accepted label, OFF! mosquito coil family, EPA Reg. No. 4822-602, notification April 8, 2019. [https://www3.epa.gov/pesticides/chem_search/ppls/004822-00602-20190408.pdf](https://www3.epa.gov/pesticides/chem_search/ppls/004822-00602-20190408.pdf) 1. Liu et al., Environ Health Perspect 2003;111(12):1454-60 (PMID 12948883). [https://pubmed.ncbi.nlm.nih.gov/12948883/](https://pubmed.ncbi.nlm.nih.gov/12948883/) 1. U.S. Fire Administration (FEMA), Candle Fire Safety (page last reviewed April 1, 2023). [https://www.usfa.fema.gov/prevention/home-fires/prevent-fires/candle/](https://www.usfa.fema.gov/prevention/home-fires/prevent-fires/candle/) Last reviewed 2026-10-02 · every claim on this page is sourced above ## Mosquito Repellent for Kids: CDC Age Rules, None Under 2 Months URL: https://longsleeve.com/blog/mosquito-repellent-for-kids > No insect repellent on babies under 2 months, the CDC says; use netting. No oil of lemon eucalyptus or PMD under 3. AAP caps DEET at 30% for kids. Source: https://longsleeve.com/blog/mosquito-repellent-for-kids By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 6, 2026 · Updated September 13, 2026 **Short answer:** The CDC says not to use insect repellent on babies younger than 2 months old. Use mosquito netting over strollers and carriers instead. For older children, CDC and AAP guidance says adults should apply repellent to their own hands first, keep it off children's hands, eyes, mouth, cuts, and irritated skin, and follow the product label. CDC and AAP also say not to use products containing oil of lemon eucalyptus or PMD on children younger than 3 years old. That guidance comes from the CDC, the EPA, and the American Academy of Pediatrics. Their wording differs in places, which is the first thing below. The label on the bottle outranks it. ### What is the youngest age for insect repellent? The CDC's mosquito bite prevention fact sheet is blunt. Do not use insect repellent on babies younger than 2 months old. Instead, dress your child in clothing that covers arms and legs, and cover strollers and baby carriers with mosquito netting. The National Pesticide Information Center reads it the same way: the AAP does not recommend insect repellents for children younger than two months, and the CDC recommends DEET can be used on children older than two months. The EPA, which regulates repellents, frames it differently. It says DEET has been approved for use on children with no age restriction, and that there is no restriction on the percentage of DEET in the product for use on children, since data do not show any difference in effects between young animals and adult animals in tests done for product registration. The [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html)'s Yellow Book, written for providers advising travelers, says repellents containing DEET, picaridin, IR3535, and 2-undecanone can be used on children without age restriction. Those answer different questions. The EPA statement describes what registration data support; the 2-month line is practical guidance for parents. NPIC resolves it at the shelf: check the label for a minimum age, and if none is there, the EPA has not restricted the product by age. The AAP adds a note that is easy to misread. Until infants and children are at least 2 years old, it says, their skin may be different than the skin of an older child or adult, so apply DEET sparingly when needed and weigh the risk of serious insect-spread illness against the possible risk of absorbing chemicals into the body. Parents of newborns and premature infants should be especially cautious. That is a caution about how much, not a ban. ### Which repellent ingredients have an age limit for kids? The CDC recommends EPA-registered insect repellents with one of six active ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), and 2-undecanone. Two of those six carry a pediatric age limit. The [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html) and the AAP both say not to use products containing OLE or PMD on children younger than 3 years old, and the Yellow Book gives the reason: to avoid potential allergic skin reactions. The label detail matters. According to the [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely), some oil of lemon eucalyptus products should not be used on children under three, while certain products with OLE as the sole active ingredient at 30% or less carry no such restriction. The Yellow Book agrees, and says parents should always read the label before use. Both the CDC and the AAP also warn off pure, unformulated oil of lemon eucalyptus: per the CDC it has not undergone validated testing for safety and efficacy and is not registered with the EPA as an insect repellent. On concentration, the [AAP](https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx) publishes rough protection times: 10% DEET provides protection for about 2 hours, 30% protects for about 5 hours, and anything over 50% does not provide longer protection. The AAP's own limit for kids is that repellents used on children should contain no more than 30% DEET, applied only once a day. ### How should you apply repellent to a child? Because [children frequently put their hands in their eyes and mouths](https://longsleeve.com/blog/bug-spray-on-face), the EPA recommends that all repellent products carry these precautionary statements on labels: do not allow children to handle this product, do not apply to children's hands, and when using on children, apply to your own hands and then put it on the child. The CDC and its Yellow Book say the same: adults should apply repellent to their own hands first, then gently spread it on the child's exposed skin. The rest, condensed: - Do not apply to a child's hands, eyes, mouth, cuts, or irritated skin. Apply sparingly around ears. - Never spray directly onto a child's face. Spray a little on your hands first, then rub it on. - Apply only to exposed skin and the outside of clothing. Not under clothing. - Use just enough to cover clothing and exposed skin. Using more does not make it more effective, and the Yellow Book notes that heavy application and saturation are generally unnecessary. - Choose sticks, lotions, or unpressurized sprays, and spray in open areas to avoid breathing them in. - Help apply repellent on young children, and supervise older ones who apply it themselves. - Keep repellents out of young children's reach. The EPA says to store them in a locked cabinet or garden shed. - Skip repellent candles if your child is at risk of breathing problems from fumes, per the AAP. ### What should you do when a child comes back indoors? [Wash it off](https://longsleeve.com/blog/wash-off-bug-spray). The EPA's recommended child label language says that after returning indoors you should wash your child's treated skin and clothes with soap and water, or bathe. The AAP adds the laundry step: wash their clothing before they wear it again. [NPIC](http://npic.orst.edu/factsheets/repellents.html) gives the reason: children may mishandle a bottle or lick treated skin. In tick country, add a tick check. The CDC recommends checking clothing for ticks, examining gear and pets, and doing a full body check on you and your child, including under the arms, in and around the ears and hair, back of the knees, and around the waist. Showering within two hours of coming indoors has been shown to reduce your risk of getting Lyme disease, per the [CDC](https://www.cdc.gov/ticks/prevention/index.html). If you find one, see [tick removal](https://longsleeve.com/blog/tick-removal). ### What protects a baby who is too young for repellent? Barriers and habitat. The CDC's first two tips for babies and children are to dress your child in clothing that covers arms and legs and to cover strollers and baby carriers with mosquito netting. NPIC says the same for infants less than two months old. The AAP's clothing list is more specific: long pants, a lightweight long-sleeved shirt, socks, and closed shoes when your child will be exposed, plus a broad-brimmed hat to keep insects away from the face. For the yard, the CDC recommends screens on windows and doors, air conditioning where available, and emptying or scrubbing anything that holds water once a week. More in [why mosquitoes bite some people more](https://longsleeve.com/blog/why-mosquitoes-bite-some-people), [standing water and mosquito control](https://longsleeve.com/blog/standing-water-mosquito-control), and [tick season timing](https://longsleeve.com/blog/tick-season-when). For ticks, the AAP calls permethrin the most effective product, applied to your child's clothing and gear and not to skin. The CDC recommends treating clothing and gear with products containing 0.5% permethrin, or buying pretreated items, and says not to use it directly on skin. NPIC adds the rule that gets skipped: do not apply permethrin to clothing while it is being worn, and let treated items dry first. ### What about sunscreen and combination products? Order matters. If you are using sunscreen, the CDC says, apply it first and insect repellent second. NPIC adds that the CDC recommends [letting the sunscreen dry first](https://longsleeve.com/blog/bug-spray-and-sunscreen), and notes that using both can increase repellent absorption through skin. On combination products, the AAP advises against sunscreen and repellent in one bottle: sunscreen needs reapplying every 2 hours in the sun and after swimming or sweating, and a combination product applied that often may expose your child to too much repellent. NPIC reports the CDC does not recommend combined products. ### Do natural repellents and gadgets work for children? The AAP's answer is a qualified no. Natural insect-repellent ingredients such as citronella, geranium, peppermint, and soybean oil are deemed safe but have not been approved for effectiveness by the EPA, most keep insects away for only a short time, and some can cause skin irritation. Products not proven effective against mosquitoes, per the AAP, include wristbands soaked in chemical repellents and ultrasonic devices. The CDC's Yellow Book is blunter: ingestion of vitamin B or garlic, and wearing sound-emitting devices or repellent-impregnated wristbands, are ineffective. The AAP frames when this matters: natural and alternative repellents may be good if there is no concern about a serious insect-borne illness, but if there is a health concern, such as Lyme disease in an area known to have ticks, then DEET, picaridin, or another approved effective product should be used. See [Lyme disease prevention](https://longsleeve.com/blog/lyme-disease-prevention) and [West Nile virus](https://longsleeve.com/blog/west-nile-virus). ### What if a child reacts to an insect repellent? The AAP's steps: stop using the product, wash your child's skin with soap and water, then call your child's pediatrician or Poison Help at 1-800-222-1222. Take the container to the doctor's office. The [AAP](https://www.aap.org/en/patient-care/environmental-health/promoting-healthy-environments-for-children/insect-repellents/)'s clinician-facing page adds that you should call 911 if there is a serious reaction such as trouble breathing or a seizure. On DEET, the AAP says products containing it can cause skin rashes, especially at high concentrations, but that these reactions are rare. If the bite is the problem, see [bite treatment](https://longsleeve.com/blog/mosquito-bite-treatment). ### About Longsleeve Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients. None of this replaces medical advice. The AAP's closing line is the one to end on: talk with your child's pediatrician if you have any questions about protecting your child from insect bites. ### Common questions **Can my kid apply their own repellent?** The EPA recommends that repellent labels say children should not handle the product, and that adults apply it to their own hands first, then put it on the child. The AAP says to help apply repellent on young children and supervise older ones who use these products. **Is oil of lemon eucalyptus okay for a 2-year-old?** The CDC and the AAP both say not to use products containing OLE or PMD on children younger than 3 years old, and the Yellow Book gives the reason as avoiding potential allergic skin reactions. The EPA notes one exception: certain products with OLE as the sole active ingredient at 30% or less carry no under-three restriction. Read the label. **Can babies under 2 months use insect repellent?** No: the CDC says do not use insect repellent on babies younger than 2 months old; instead, dress the child in clothing that covers arms and legs and cover strollers and baby carriers with mosquito netting. NPIC reports that the AAP does not recommend insect repellents for children younger than two months and that the CDC recommends DEET can be used on children older than two months; after that, the CDC's first instruction for using repellent on a child is to always follow label instructions. On an infected bite, the CDC says to see a healthcare provider if symptoms worsen. **What DEET percentage is recommended for kids?** No more than 30%: the AAP says that when used on children, insect repellents should contain no more than 30% DEET. 10% DEET protects for about 2 hours and 30% for about 5 hours, per the AAP, and anything over 50% does not protect longer. More on DEET and children is in our DEET evidence page . **Can a 1-year-old use picaridin?** Yes, by the CDC's guidance: the CDC Yellow Book says repellents containing DEET, picaridin, IR3535, and 2-undecanone can be used on children without age restriction, and a 1-year-old is well past the CDC's rule of no insect repellent on babies younger than 2 months old. Follow the label, which is the CDC's first instruction for using repellent on a child; NPIC says that if no age limit is on the label, the EPA has not put age restrictions on the product. How the two compare for a child is in picaridin versus DEET . ### Related reading - [Picaridin vs DEET: What the Sources Actually Say](https://longsleeve.com/blog/picaridin-vs-deet). Both actives, side by side, per EPA, CDC, AAP, and NPIC. - [DEET Safety: What the Evidence Actually Says](https://longsleeve.com/blog/deet-safety-evidence). EPA reviews, poison-center data, and the folklore, sorted. - [Standing Water and Mosquito Control](https://longsleeve.com/blog/standing-water-mosquito-control). What the CDC says to empty, and how often. - [The Asian Tiger Mosquito](https://longsleeve.com/blog/asian-tiger-mosquito). What it is, where it lives, and what it carries. - [Our almanac of mosquitoes and ticks](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC, Mosquito Bite Prevention: How to Protect Against Mosquito Bites (fact sheet, December 2, 2024). [https://www.cdc.gov/mosquitoes/pdfs/mosquitobitepreventionus_508.pdf](https://www.cdc.gov/mosquitoes/pdfs/mosquitobitepreventionus_508.pdf) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. CDC, Preventing Tick Bites. [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely](https://www.epa.gov/insect-repellents/using-insect-repellents-safely) 1. American Academy of Pediatrics, HealthyChildren.org: How to Choose an Insect Repellent for Your Child (Sophie J. Balk, MD, FAAP, June 21, 2024). [https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx](https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx) 1. American Academy of Pediatrics, Insect Repellents (Promoting Healthy Environments for Children). [https://www.aap.org/en/patient-care/environmental-health/promoting-healthy-environments-for-children/insect-repellents/](https://www.aap.org/en/patient-care/environmental-health/promoting-healthy-environments-for-children/insect-repellents/) 1. National Pesticide Information Center, Insect Repellents Fact Sheet. [http://npic.orst.edu/factsheets/repellents.html](http://npic.orst.edu/factsheets/repellents.html) 1. CDC, About Mosquito Bites, updated June 21, 2024. [https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html](https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html) Last reviewed 2026-08-06 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Avon Skin-So-Soft Bug Guard Plus IR3535 Insect Repellent Spray](https://longsleeve.com/repellent-index/avon-skin-so-soft-bug-guard-plus-ir3535-insect-repellent-spray) or [Coleman Skin Smart Insect Repellent](https://longsleeve.com/repellent-index/coleman-skin-smart-insect-repellent). ## Mosquito Repellent in Pregnancy: CDC Guidance, DEET, Picaridin URL: https://longsleeve.com/blog/mosquito-repellent-pregnancy > CDC covers picaridin and DEET in pregnancy. MotherToBaby: picaridin unstudied in human pregnancy; the one DEET trial covered trimesters two and three only. Source: https://longsleeve.com/blog/mosquito-repellent-pregnancy By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 26, 2026 · Updated September 13, 2026 The CDC's guidance is direct: "When used as directed, EPA-registered insect repellents are proven safe and effective, even for pregnant and breastfeeding women." The registered actives it lists include DEET, picaridin, IR3535 and oil of lemon eucalyptus. Look for an EPA registration number on the label, follow the directions, and talk to your clinician about your situation. Pregnancy turns every product label into a research project, and repellent is one where skipping it carries its own risk: mosquito bites are not just an itch, they are how several diseases travel. So this page does one thing: it lays out, verbatim, what the CDC and EPA actually say about repellent use in pregnancy, with nothing added. ### What does the CDC say about repellents in pregnancy? The clearest sentence in this whole subject sits in the CDC's mosquito prevention guidance: "When used as directed, EPA-registered insect repellents are proven safe and effective, even for pregnant and breastfeeding women." **Short answer:** CDC guidance says, “When used as directed, EPA-registered insect repellents are proven safe and effective, even for pregnant and breastfeeding women.” The active ingredients CDC lists include DEET, picaridin, IR3535, and oil of lemon eucalyptus. Look for an EPA registration number, follow the label directions, and talk to your clinician about your situation. ### Which active ingredients does the CDC list? The same guidance lists the registered active ingredients to look for: - DEET - Picaridin (known as KBR 3023 and icaridin outside the United States) - IR3535 - Oil of lemon eucalyptus (OLE), a plant-derived ingredient - Para-menthane-diol (PMD) - 2-undecanone, a plant-derived ingredient On picaridin, since it is the one we know best: the National Pesticide Information Center describes it as a synthetic compound made to resemble piperine, the natural compound found in the group of plants used to produce black pepper, and states that it repels insects, ticks and chiggers. ### What do the agencies say about picaridin in pregnancy? The CDC's pregnancy sentence sits above a list of active ingredients that includes picaridin, so the class statement covers it. MotherToBaby, the fact-sheet service of the Organization of Teratology Information Specialists, says picaridin, PMD, IR3535 and 2-undecanone have not been studied in human pregnancy, and that when used as directed only low amounts are expected to be absorbed through the skin into the bloodstream. [NPIC](https://npic.orst.edu/factsheets/archive/Picaridintech.html)'s technical fact sheet says no human data were found on the teratogenic or reproductive effects of picaridin. The developmental data come from animals. NPIC reports that researchers applied large amounts of picaridin to the skin of rats and rabbits for up to two years; the parents' skin thickened, became irritated and developed dark spots, and there were no effects on the offspring. NPIC's technical sheet adds a gestation study in rats and rabbits in which no treatment-related malformations were observed in the fetuses, and a two-generation study in rats whose researchers concluded that chronic skin exposure at doses as high as 200 mg/kg did not result in reproductive toxicity. In short: the CDC's statement covers picaridin, NPIC's dermal studies in rats and rabbits found no effects on the offspring, and MotherToBaby says it has not been studied in human pregnancy. The DEET comparison is in [picaridin versus DEET](https://longsleeve.com/blog/picaridin-vs-deet). That gap is the thing to raise with your OB or midwife; MotherToBaby's own rule is that its fact sheet should not take the place of medical care and advice from your healthcare provider. ### What about DEET in the first trimester? No trial behind this page tested a repellent in the first trimester; the one human trial covered the second and third trimesters only, and the CDC's sentence carries no trimester qualifier. McGready and colleagues, in the American Journal of Tropical Medicine and Hygiene in 2001, assessed daily DEET use in the second and third trimesters inside a double-blind randomized trial of insect repellents in 897 pregnant women. It found no adverse neurologic, gastrointestinal or dermatologic effects, DEET crossing the placenta and turning up in 8 percent of cord blood samples from a randomly selected subgroup of 50 DEET users, and no adverse effects on survival, growth or development at birth or at one year. The authors called it the first study to document the safety of DEET applied regularly in the second and third trimesters, which is also where the evidence stops. MotherToBaby says most studies do not find DEET use increases the chance of birth defects, and reports one study suggesting hypospadias, a penile birth defect, was more common in males exposed to DEET early in pregnancy, which MotherToBaby says did not prove causation. A drugstore DEET spray meets the CDC's sentence on the same terms: EPA-registered, used as directed. EPA reports that registered skin formulations run from 5 to 99 percent DEET, so read the percentage and directions; more in [our DEET evidence page](https://longsleeve.com/blog/deet-safety-evidence). The first trimester, with no trial behind it, is the question to take to your OB or midwife. ### Do citronella candles, coils, and spatial repellents count? None of the sources behind this page addresses the safety of citronella candles, mosquito coils or spatial repellents in pregnancy, so this section gives no verdict on them. The CDC's sentence covers EPA-registered insect repellents used as directed, and the label says whether yours is one. The [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) Yellow Book describes spatial repellents as aerosol insecticide sprays, vaporizing mats and mosquito coils containing active ingredients such as metofluthrin and allethrin. It says that although many of these products have repellent or insecticidal activity under certain conditions, they have not yet been adequately evaluated in peer-reviewed studies for efficacy in preventing vector-borne diseases, that travelers should supplement them with an EPA-registered repellent on skin or clothing, and to use them with caution, avoiding direct inhalation of spray or smoke. On wristbands, the Yellow Book says the effectiveness of non-EPA-registered repellents is unknown and travelers should avoid them, and that repellent-impregnated wristbands are ineffective. MotherToBaby says natural repellents not on the EPA list, including citronella candles and wristbands, might not work and are not recommended where insect-borne disease is a risk, and that plant oils such as citronella have not been studied in human pregnancy. Candles are covered in [mosquito repellent candles](https://longsleeve.com/blog/mosquito-repellent-candles), the oils in [citronella and plant repellents](https://longsleeve.com/blog/citronella-and-plant-repellents), the wider field in [natural repellents](https://longsleeve.com/blog/natural-repellents). If a coil, vaporizing mat or candle is part of your evenings, take its label to your OB or midwife with the repellent question; the agencies cited here have not answered it. ### How should you apply repellent while pregnant? The application rules are the same ones EPA gives everyone, and they are worth following precisely because the CDC's safety statement is tied to them: - **Read and follow the label directions,** and be sure you understand how much to apply. - **Apply only to exposed skin and/or clothing.** Do not use under clothing. - **Keep it away from eyes and mouth** and apply sparingly around ears. With sprays, spray your hands first, then apply to your face. - **Never apply over cuts, wounds, or irritated skin.** Pregnancy makes some skin more reactive than usual; this rule is easy to forget on a scraped ankle and worth remembering. - **Wash treated skin and clothes with soap and water** after returning indoors. If you are also caring for small children, EPA's rule for them: do not apply repellent to children's hands; apply it to your own hands first, then put it on the child. ### What else does the CDC recommend besides repellent? The registration number is worth a sentence of its own, because it is the difference between the two kinds of products on the shelf. A repellent with an EPA Reg. No. on its label has been through federal registration, and that number is what connects the bottle in your hand to the CDC's sentence above. A citronella candle or an essential-oil bracelet has no such number, and no such sentence. The CDC's guidance points you to the registered aisle. Repellent is one line in the [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html)'s four-part prevention list: use EPA-registered insect repellents, wear loose-fitting long-sleeved shirts and pants, wear clothing and gear treated with permethrin, and control mosquitoes indoors and outdoors. The clothing line matters in pregnancy for a simple reason: fabric is protection with no application questions at all, and pairing it with repellent on the skin that stays exposed is the full CDC picture. If you want to compare specific registered products, EPA's search tool lets you filter by protection time and active ingredient, and [our Repellent Index](https://longsleeve.com/repellent-index) lets you compare all 631 registered skin repellents by what their federal labels actually claim. ### Does pregnancy change where you should travel? Yes, in the [CDC](https://www.cdc.gov/yellow-book/hcp/family-travel/pregnant-travelers.html)'s guidance it does: the CDC Yellow Book tells pregnant women to reconsider travel to areas with a Zika outbreak and to avoid or delay travel to malaria-endemic areas if possible. On bites it is short: pregnant travelers should avoid mosquito bites. On Zika, the Yellow Book says birth defects from infection during pregnancy include brain, eye and neurodevelopmental abnormalities, and that pregnant women should reconsider travel to outbreak areas and, for the duration of the pregnancy, avoid sex or use condoms with anyone who has traveled to a risk area. It says adverse fetal outcomes have been noted with chikungunya and dengue, so pregnant women should also reconsider travel to outbreak areas for either. Malaria gets the strongest language. The Yellow Book says it can be much more serious in pregnant than in non-pregnant women, with high risks of illness and death for mother and fetus, and that pregnant women should avoid or delay travel to malaria-endemic areas if possible because no prophylactic regimen provides complete protection; if travel is unavoidable, avoid mosquito bites and use an effective prophylactic regimen. [CDC](https://www.cdc.gov/malaria/hcp/risk-assessment/index.html)'s malaria risk-assessment page says the same to clinicians: advise women who are pregnant or likely to become pregnant to avoid travel to malaria areas if possible, and if travel cannot be deferred, an effective chemoprophylaxis regimen is essential. CDC writes that advice for clinicians, so bring the itinerary, with dates and trimester, to your OB or midwife and a travel medicine clinician before you book. ### The part that belongs to your clinician This page reports what the agencies publish for the general case. Your pregnancy is a specific case. Bring the repellent question to your OB, midwife or family doctor, especially if travel to an area with mosquito-borne disease is on your calendar; they can weigh your destination, trimester and history in a way no label or blog post can. Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours, and its accepted federal label also carries the claim "Repels biting flies, stable flies, black flies, gnats, chiggers, sand flies and Scottish biting midges (no see-ums) for up to 8 hours." It is fragrance-free, with nine disclosed ingredients, every one listed on [the ingredients page](https://longsleeve.com/ingredients). ### Short answers **Is insect repellent safe during pregnancy?** The CDC's statement: when used as directed, EPA-registered insect repellents are proven safe and effective, even for pregnant and breastfeeding women. The conditions are the substance: EPA-registered products, used as the label directs. For your individual situation, ask your clinician. **Is picaridin okay to use while pregnant?** Picaridin is on the CDC's list of EPA-registered active ingredients covered by its guidance for pregnant and breastfeeding women. NPIC describes it as a synthetic compound made to resemble piperine from the plants used to produce black pepper. As with any repellent in pregnancy, use it as the label directs and raise it with your clinician. **Is DEET safe in pregnancy?** The CDC's list of registered actives covered by its pregnancy guidance includes DEET, alongside picaridin and the others above. The CDC's condition applies across the whole list: used as directed, per the product label. **Which repellent does the CDC recommend most for pregnancy?** The CDC does not single one out. Its guidance covers the class: EPA-registered repellents with the listed actives (DEET, picaridin, IR3535, OLE, PMD, 2-undecanone), used as directed. The choice within that list is yours and your clinician's; the registration number and the label directions are the non-negotiable parts. MotherToBaby says the CDC, the American College of Obstetricians and Gynecologists and other major health organizations recommend the use of insect repellents in people who are pregnant or breastfeeding to protect against insect bites that spread disease, and the CDC Yellow Book says that other than its listed safety tips, EPA does not recommend any additional precautions for using registered repellents on women who are pregnant or lactating. MotherToBaby says its fact sheet should not take the place of medical care and advice from your healthcare provider, and neither should this page. **What about breastfeeding?** The CDC's sentence covers it explicitly: EPA-registered repellents used as directed are proven safe and effective "even for pregnant and breastfeeding women." EPA's general rule to wash treated skin after coming indoors applies as usual. The CDC Yellow Book says the same, that EPA-registered products are considered safe when used as directed, even for pregnant and breastfeeding women. MotherToBaby says there is little data on the use of insect repellents during breastfeeding, that it is important to consider the benefit of using them to prevent illness, to follow the same instructions as during pregnancy, and not to apply repellent to the nipple area so the nursing child does not get any in the mouth; MotherToBaby also says to talk with your healthcare provider about all your breastfeeding questions. **Are you more likely to get bitten by mosquitoes when pregnant?** One study says yes, for one mosquito: a study published in The Lancet on 3 June 2000 found that pregnant women attracted twice the number of Anopheles gambiae complex mosquitoes, the predominant African malaria-carrying mosquito, as their non-pregnant counterparts, a mean of 6.33 per night against 3.1 after adjusting for variation between huts and trials. The authors named increased heat and increased release of volatile substances from the skin surface as two physiological factors behind it. That study, and the rest of what is known about who gets bitten, is in why mosquitoes bite some people more than others . Related reading: [repellent for babies and kids](https://longsleeve.com/blog/mosquito-repellent-for-kids), [dengue and travel](https://longsleeve.com/blog/dengue-travel), and [every ingredient in Longsleeve](https://longsleeve.com/ingredients). ### Related reading - [Mosquito Repellent for Kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). CDC and AAP age rules. - [DEET Safety](https://longsleeve.com/blog/deet-safety-evidence). EPA reviews, CDC guidance, kids, and common questions. - [Picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet). Duration, kids, ticks, and materials. - [Dengue and Travel](https://longsleeve.com/blog/dengue-travel). Day-Biting mosquitoes, warning signs, and prevention. More Longsleeve in your Google feed: ### Sources 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. NPIC, Picaridin General Fact Sheet. [https://npic.orst.edu/factsheets/PicaridinGen.html](https://npic.orst.edu/factsheets/PicaridinGen.html) 1. MotherToBaby Fact Sheets (Organization of Teratology Information Specialists), Insect Repellents, NCBI Bookshelf NBK582767, August 2024. [https://www.ncbi.nlm.nih.gov/books/NBK582767/](https://www.ncbi.nlm.nih.gov/books/NBK582767/) 1. NPIC, Picaridin Technical Fact Sheet, reviewed March 2009. [https://npic.orst.edu/factsheets/archive/Picaridintech.html](https://npic.orst.edu/factsheets/archive/Picaridintech.html) 1. McGready R, et al., Safety of the insect repellent N,N-diethyl-M-toluamide (DEET) in pregnancy, American Journal of Tropical Medicine and Hygiene, October 2001, volume 65, issue 4, pages 285 to 289 (PubMed 11693870). [https://pubmed.ncbi.nlm.nih.gov/11693870/](https://pubmed.ncbi.nlm.nih.gov/11693870/) 1. EPA, DEET, last updated May 27, 2026. [https://www.epa.gov/insect-repellents/deet](https://www.epa.gov/insect-repellents/deet) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods, April 23, 2025. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. CDC Yellow Book, Pregnant Travelers, April 23, 2025. [https://www.cdc.gov/yellow-book/hcp/family-travel/pregnant-travelers.html](https://www.cdc.gov/yellow-book/hcp/family-travel/pregnant-travelers.html) 1. CDC, Malaria Risk Assessment for Travelers, May 15, 2024. [https://www.cdc.gov/malaria/hcp/risk-assessment/index.html](https://www.cdc.gov/malaria/hcp/risk-assessment/index.html) 1. Lindsay S, et al., Effect of pregnancy on exposure to malaria mosquitoes, The Lancet, 3 June 2000, volume 355, issue 9219, page 1972 (PubMed 10859048). [https://pubmed.ncbi.nlm.nih.gov/10859048/](https://pubmed.ncbi.nlm.nih.gov/10859048/) Last reviewed 2026-08-26 · every claim on this page is sourced above ## When Is Mosquito Season? By Region, Temperature, and Rain URL: https://longsleeve.com/blog/mosquito-season-by-region > Mosquito season by U.S. region, temperature, rainfall, and disease timing, with health-department guidance on when activity starts, peaks, and ends. Source: https://longsleeve.com/blog/mosquito-season-by-region By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 16, 2026 Mosquito season depends on where you are. New York's health department says mosquitoes there are active from early summer until late fall, and that in warm southern states, disease-spreading mosquitoes are active year round. Nebraska's health department says activity continues until a sustained hard freeze. The CDC puts West Nile diagnoses at a typical late August to early September peak. Mosquito season is really three calendars stacked on each other: temperature, species, and rainfall. ### What temperature does it take for mosquitoes to become active? There is no single switch. Thresholds are species-specific. In Minnesota, the Metropolitan Mosquito Control District reports that spring *Aedes* mosquitoes overwinter as eggs in woodland pools and marshes, and that "when temperatures exceed ~39 degrees Fahrenheit, spring *Aedes* eggs hatch." The Washington State Department of Health gives a higher number for a different group. Writing about the floodwater species *Aedes vexans* and *Ae. sticticus* along the Columbia River, its 2025 guidance says that when temperatures are below 45 to 50 degrees F, the eggs of these species are dormant, so only some of the eggs hatch after a spring flood. **Short answer:** Mosquito season depends on region, temperature, species, and rain. New York health guidance puts mosquito activity from early summer until late fall, while warm southern states can have disease-spreading mosquitoes year-round. Nebraska guidance says activity continues until a sustained hard freeze, and CDC West Nile diagnoses typically peak in late August to early September. For disease transmission specifically, Shocket and colleagues modeled ten mosquito and virus pairs in eLife in 2020. Transmission is optimized at intermediate temperatures of 23 to 26 degrees C, roughly 73 to 79 degrees Fahrenheit, and incidence of human neuroinvasive West Nile disease responded unimodally to average summer temperature, peaking at 24 degrees C. Among the three North American *Culex* vectors, the modeled lower thermal limit for West Nile ranged from 19.0 degrees C in *Cx. quinquefasciatus* to 12.2 in *Cx. tarsalis*. The authors flagged their own limits: the human disease data "did not show evidence for lower or upper thermal limits." ### How long does mosquito season last in your region? The New York State Department of Health draws the contrast in two sentences. Its own state: mosquitoes "are active from early summer until late fall in New York State." Elsewhere: "In southern states that have warm year-round weather, mosquitoes that can spread diseases are active throughout the year." Agency calendars fill in the middle. Washington State says mosquito surveillance "should typically begin in April or May and continue through September or early October." Minnesota tells residents their risk runs "primarily July through September." Nebraska's health department frames the endpoint as a hard freeze: "Until we experience a sustained hard freeze, we will continue to see mosquito activity." Modeling caps the northern season hard. Mordecai and colleagues, in PLOS Neglected Tropical Diseases in 2017, found dengue, chikungunya, and Zika transmission occurring between 18 and 34 degrees C, and concluded that "transmission in temperate areas is limited to at most three months per year even if vectors are present." That is transmission suitability, not how many months mosquitoes bite. Burden is uneven too: the [EPA](https://19january2021snapshot.epa.gov/climate-indicators/climate-change-indicators-west-nile-virus_.html)'s West Nile indicator puts average annual incidence "highest in parts of the Southwest, the Mississippi Delta region, the Great Plains, and the Rocky Mountain region." ### Which species dominate at which point in the season? Minnesota's control district publishes a month-by-month account. Spring *Aedes* hatch from overwintered eggs as snow melts, and by mid-June they "begin to die out." Cattail mosquitoes take one annual brood "peaking around the 4th of July." Then *Culex* takes over: "*Culex restuans* decrease in numbers and *Culex pipiens* reach their peak in mid-August. Due to these mosquitoes' large numbers, August becomes the time of year where people are most at risk to contract West Nile Virus." That late-summer *Culex* peak is why bite season and disease season are not the same thing. The [CDC](https://www.cdc.gov/west-nile-virus/about/index.html) says West Nile infections happen "during mosquito season, which starts in the summer and continues through fall (typically June through October)," with diagnoses typically peaking "in late August to early September." The same window shows up in Georgia, where University of Georgia Extension has described southern house mosquitoes as most active, and West Nile transmission as most common, during late summer and early fall and the period from August 15 to September 15. Behavior changes with the handoff, which decides when you need cover. The CDC says adult *Culex* "are most active from dusk to dawn," and that some "prefer to live near and bite birds," biting people when other animals are not nearby. Container *Aedes* are the opposite: UGA Extension calls [Asian tiger mosquitoes](https://longsleeve.com/blog/asian-tiger-mosquito) "voracious daytime feeders" that "lay eggs and develop in anything that can hold water," naming clogged downspouts, watering cans, toys, and plant saucers. Per the CDC, these species "will only fly a few blocks" in their lifetime, so the problem is usually your yard or your neighbor's. ### Why does standing water after rain drive a local surge? Because a whole class of mosquito spends the dry weeks as eggs waiting for exactly that. Penn State Extension describes the floodwater group depositing eggs "singly on damp soil in grassy or woodland depressions" that flood intermittently, where they "may remain dormant and viable on the soil for some time until the area is flooded." Then: "Typically, large numbers hatch simultaneously. The larvae develop synchronously, and adults begin to appear as early as 7 days after flooding." Minnesota's control district adds a rain gauge. Summer floodwater mosquitoes take "around a week to mature into adults," and "with every rainfall exceeding an inch, a new brood of summer floodwater mosquitoes will hatch and emerge." Container species run the same trigger at smaller scale. The CDC says *Aedes* eggs stick to container walls above the waterline, "can survive drying out for up to 8 months," and hatch "when water (from rain or a sprinkler) covers the eggs." A sprinkler counts, which is how a rain-free week still produces mosquitoes. After major weather the CDC is specific about sequence. The CDC expects nuisance and floodwater mosquitoes to increase "in the weeks after flooding." Separately, "the types of mosquitoes that can spread viruses may increase 2 weeks after a hurricane," including "in areas that did not flood but received more rainfall than usual," and "it can take several more weeks before mosquitoes could start spreading viruses to people." The [CDC](https://www.cdc.gov/mosquitoes/response/index.html) also states that "an increase in the number of people getting sick from germs spread by mosquitoes is not expected after flooding." ### What do public health agencies recommend during mosquito season? The CDC's advice is the same all season: - Use EPA-registered insect repellents with one of these active ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone. Look for an EPA registration number on the label. - Wear loose-fitting, long-sleeved shirts and pants, plus clothing and gear treated with permethrin. The CDC says not to use permethrin products directly on skin. - Use screens on windows and doors, repair holes, and use air conditioning when available. - Once a week, empty and scrub, turn over, cover, or throw out items that hold water: tires, buckets, toys, pools, birdbaths, flowerpot saucers. - The CDC advises against products containing oil of lemon eucalyptus or para-menthane-diol on children under 3 years old. More in our guide to [repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). State agencies add local timing. New York tells residents to cover skin "at sunrise, sunset, and early in the evening when mosquitoes are most active." Minnesota frames it as knowing when and where you are at risk: July through September, open agricultural areas for West Nile virus, wooded areas for La Crosse and Jamestown Canyon viruses. Nebraska's state epidemiologist adds the follow-up: "If you experience symptoms such as fever, headache, fatigue, or body aches after being bitten, contact a healthcare provider and mention your recent mosquito bite." Any decision about testing or treatment belongs with your clinician. ### When does mosquito season actually end? Later than most people assume, and not on a date. Washington State's guidance notes that all life stages except pupae can overwinter, that adults "hibernate in basements, culverts, mines, or other protected areas," and that eggs in floodplain soil "hatch when flooded, even several years later." Minnesota's control district describes adult *Culex* searching out "barns, caves, and any other warm habitat." Farther south, some of that storage is barely dormant. The CDC notes *Aedes* eggs "can even survive a winter in the southern United States," and the EPA's indicator points out that "mild winters and drought have been associated with West Nile virus disease outbreaks." ### Where Longsleeve fits Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients. ### Common questions **What temperature do mosquitoes stop being active at?** There is no single number, and the published thresholds describe eggs rather than adults. Minnesota's Metropolitan Mosquito Control District reports spring Aedes eggs hatching above about 39 degrees Fahrenheit. Washington State's health department says that below 45 to 50 degrees F, eggs of the floodwater species Aedes vexans and Ae. sticticus are dormant. For the end of the season, Nebraska's health department tells residents to expect activity until a sustained hard freeze. **Is there a mosquito season in the South, or is it year round?** The New York State Department of Health says that in southern states with warm year-round weather, mosquitoes that can spread diseases are active throughout the year. The same 2017 modeling in PLOS Neglected Tropical Diseases found tropical and subtropical regions suitable for extended seasonal or year-round transmission of dengue, chikungunya, and Zika. **Why are mosquitoes worse about a week after heavy rain?** Floodwater mosquitoes lay eggs on damp soil that stay dormant until flooding. Penn State Extension reports that large numbers hatch at once and that adults "begin to appear as early as 7 days after flooding." Minnesota's Metropolitan Mosquito Control District reports every rainfall over an inch producing a new brood of summer floodwater mosquitoes. **When is West Nile virus risk highest?** The CDC says infections occur during mosquito season, typically June through October, with diagnoses typically peaking in late August to early September. Minnesota's control district reports Culex pipiens peaking in mid-August, and University of Georgia Extension points to August 15 through September 15 in Georgia. More in our West Nile virus guide . ### Related reading - [West Nile Virus in NYC, 2026](https://longsleeve.com/blog/west-nile-virus-nyc). What the late-season peak looks like in New York City this year. - [Standing water mosquito control](https://longsleeve.com/blog/standing-water-mosquito-control). The container-by-container version of the rainfall problem. - [West Nile virus](https://longsleeve.com/blog/west-nile-virus). The disease behind the late-summer *Culex* peak. - [When is tick season?](https://longsleeve.com/blog/tick-season-when) The other seasonal calendar, running on different thresholds. - [Why mosquitoes bite some people more](https://longsleeve.com/blog/why-mosquitoes-bite-some-people). What the research actually supports. - [The field guide](https://longsleeve.com/facts). Sourced field guide to species, ranges, and diseases. More Longsleeve in your Google feed: ### Sources 1. CDC, About West Nile. [https://www.cdc.gov/west-nile-virus/about/index.html](https://www.cdc.gov/west-nile-virus/about/index.html) 1. CDC, About *Culex* Mosquitoes. [https://www.cdc.gov/mosquitoes/about/culex-mosquitoes.html](https://www.cdc.gov/mosquitoes/about/culex-mosquitoes.html) 1. CDC, Life Cycle of *Aedes* Mosquitoes. [https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html](https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html) 1. CDC, What to Do After a Hurricane or Flood. [https://www.cdc.gov/mosquitoes/response/index.html](https://www.cdc.gov/mosquitoes/response/index.html) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. EPA, Mosquito Life Cycle. [https://www.epa.gov/mosquitocontrol/mosquito-life-cycle](https://www.epa.gov/mosquitocontrol/mosquito-life-cycle) 1. EPA, Climate Change Indicators: West Nile Virus (January 2021 archived snapshot). [https://19january2021snapshot.epa.gov/climate-indicators/climate-change-indicators-west-nile-virus_.html](https://19january2021snapshot.epa.gov/climate-indicators/climate-change-indicators-west-nile-virus_.html) 1. Washington State Department of Health, Guidance for Surveillance, Prevention, and Control of Mosquito-borne Disease, 2025 Edition (DOH 333-149). [https://doh.wa.gov/sites/default/files/legacy/Documents/Pubs//333-149.pdf](https://doh.wa.gov/sites/default/files/legacy/Documents/Pubs//333-149.pdf) 1. New York State Department of Health, Mosquitoes and Disease. [https://www.health.ny.gov/diseases/mosquitoes/](https://www.health.ny.gov/diseases/mosquitoes/) 1. Minnesota Department of Health, Mosquitoes and Mosquitoborne Diseases of Minnesota. [https://www.health.state.mn.us/diseases/mosquitoborne/mosquitobornediseases.pdf](https://www.health.state.mn.us/diseases/mosquitoborne/mosquitobornediseases.pdf) 1. Metropolitan Mosquito Control District (Minnesota), Minnesota Mosquitoes: by the Month. [https://mmcd.org/2025/01/07/minnesota-mosquitoes-by-the-month-2176/](https://mmcd.org/2025/01/07/minnesota-mosquitoes-by-the-month-2176/) 1. Nebraska Department of Health and Human Services, Mosquitoes are Still Active Despite Cooler Weather. [https://dhhs.ne.gov/Pages/Mosquitoes-are-Still-Active-Despite-Cooler-Weather.aspx](https://dhhs.ne.gov/Pages/Mosquitoes-are-Still-Active-Despite-Cooler-Weather.aspx) 1. Florida Department of Health in Monroe County, Unseasonably High Temperatures Linked to Early, Active Mosquito Season in Florida Keys, July 14, 2023. [https://monroe.floridahealth.gov/2023/07/14/unseasonably-high-temperatures-linked-to-early-active-mosquito-season-in-florida-keys/](https://monroe.floridahealth.gov/2023/07/14/unseasonably-high-temperatures-linked-to-early-active-mosquito-season-in-florida-keys/) 1. Penn State Extension, Mosquito Biology and Control. [https://extension.psu.edu/mosquito-biology-and-control](https://extension.psu.edu/mosquito-biology-and-control) 1. University of Georgia Cooperative Extension, Wet weather and heat fuel end-of-season mosquito boom, August 9, 2018. [https://extension.uga.edu/story.html?story=Mosquito-Season&storyid=7676](https://extension.uga.edu/story.html?story=Mosquito-Season&storyid=7676) 1. Shocket MS, Verwillow AB, Numazu MG, Slamani H, Cohen JM, El Moustaid F, et al. Transmission of West Nile and five other temperate mosquito-borne viruses peaks at temperatures between 23 degrees C and 26 degrees C. eLife. 2020;9:e58511. [https://elifesciences.org/articles/58511](https://elifesciences.org/articles/58511) 1. Mordecai EA, Cohen JM, Evans MV, Gudapati P, Johnson LR, Lippi CA, et al. Detecting the impact of temperature on transmission of Zika, dengue, and chikungunya using mechanistic models. PLOS Neglected Tropical Diseases. 2017;11(4):e0005568. [https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0005568](https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0005568) Last reviewed 2026-08-16 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Natural Bug Repellents: EPA Registration, Plant Oils, Evidence URL: https://longsleeve.com/blog/natural-repellents > All eight EPA-registered repellent ingredients in one table, in EPA's words, plus how to tell a registered repellent from an exempt one on the shelf. Source: https://longsleeve.com/blog/natural-repellents By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 17, 2026 · Updated September 13, 2026 **Short answer:** “Natural” is not the regulatory line that matters for bug repellents. The meaningful split is between EPA-registered products, including some plant-derived actives such as oil of lemon eucalyptus, and minimum-risk exempt products. EPA-registered repellents are evaluated for safety and effectiveness when used according to the label; exempt products are not evaluated by EPA for effectiveness. ### What counts as a natural repellent? There is no natural checkbox on a repellent label. EPA characterizes the active ingredients DEET and picaridin as conventional repellents, while OLE, PMD, IR3535, and 2-undecanone are biopesticide repellents derived from, or synthetic versions of, natural materials. Even biopesticide needs unpacking: the National Pesticide Information Center explains that oil of lemon eucalyptus and IR3535 are based on chemicals that occur in nature but are man-made ingredients, and OLE may appear on labels under its chemical name, p-menthane-3,8-diol, or PMD. EPA also pushes back on the marketing language. Minimum risk pesticide products are composed of chemicals listed on the product label, and the agency notes that claiming a product is free of chemicals is not based on facts and may be considered false or misleading. So instead of natural versus chemical, the split that actually tells you something is registered versus exempt. Registered means EPA reviewed effectiveness data. Exempt means it did not. ### Which plant-derived repellent is EPA registered? Oil of lemon eucalyptus is the headline plant-derived option. The CDC advises using EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone. PMD is the synthesized version of oil of lemon eucalyptus. On [EPA](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients)'s list of registered skin-applied active ingredients, OLE appears in 6 registered products; it contains PMD but is a separately regulated pesticide chemical. OLE is not alone; every registered active is in the table below. Registration carries weight because EPA-registered repellents have been proven effective in reducing biting by insects such as mosquitoes, as well as other arthropods such as ticks and mites. One age rule: [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html) says not to use products containing OLE or PMD on children under 3 years old. Our guide to [mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids) covers age guidance in detail. ### Which repellent ingredients are EPA registered? The full list Eight. EPA's Skin-Applied Repellent Ingredients page, last updated January 23, 2026, lists them as the "active ingredients in EPA-registered skin-applied insect repellents": catnip oil, oil of citronella, DEET, IR 3535, p-Menthane-3,8-diol, oil of lemon eucalyptus, picaridin and 2-undecanone. The table keeps EPA's order, wording and product counts as of that update. The origin column is not EPA's: it is the California Department of Public Health (CDPH) or the National Pesticide Information Center (NPIC), named in each cell. | Active ingredient | What EPA's list says | Origin, and who says so | |---|---|---| | Catnip oil | Nepeta cataria, also known as catmint; 4 products | CDPH: list limited to the registered actives most common in stores | | Oil of citronella | 3 registered products; also used in unregistered products that meet the requirements for exemption from registration | NPIC: a naturally occurring insect and animal repellent distilled from two grass varieties | | DEET | More than 500 products | CDPH: synthetic (or human-made) | | IR 3535 | 3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester; about 45 products | CDPH: synthetic, similar to a naturally occurring amino acid. NPIC: man-made, based on chemicals that occur in nature | | p-Menthane-3,8-diol (PMD) | 6 products | CDPH: the synthetic version of oil of lemon eucalyptus | | Oil of Lemon Eucalyptus | Contains PMD, but is a separately regulated pesticide chemical; 6 products | CDPH: naturally derived from the lemon eucalyptus plant. NPIC: man-made, based on chemicals that occur in nature | | Picaridin | About 40 products | CDPH: synthetic, similar to the natural compound piperine, which comes from black pepper | | 2-undecanone | Or methyl nonyl ketone; 1 product | CDPH: registered but not as commonly found; no origin given | For a product rather than an ingredient, EPA's Find the Repellent that is Right for You page carries a search tool. [EPA](https://www.epa.gov/insect-repellents/find-repellent-right-you) says you can specify mosquitoes, ticks or both, protection time, active ingredient, or other product-specific information, and that results include only skin-applied repellent products registered by EPA. Since one registered product may carry multiple marketing names, EPA says to look for the registration number on what you buy and check it against the database. EPA's own caveat: the information in this database was last updated in June 2019, and inclusion of a product is not an endorsement. Given that date, pair it with our [Repellent Index](https://longsleeve.com/repellent-index), which compares EPA-registered skin repellents side by side from federal label data. ### How do you tell a registered product from an exempt one on the shelf? By the EPA Registration Number. EPA says any registered product carries one on the label, formatted like 123456-1. An exempt product should not show one: EPA lists "EPA registration number" and "EPA establishment number" among label statements that may imply EPA review of a minimum risk product when no such review has occurred. What an exempt label must carry is the full recipe. [EPA](https://www.epa.gov/minimum-risk-pesticides/conditions-minimum-risk-pesticides)'s Condition 3 for minimum risk products says all ingredients, active and inert, must be listed on the label, the actives by label display name and percentage by weight; Condition 1 says the actives must only be those listed in 40 CFR 152.25(f)(1), a list EPA publishes. So every active on an exempt label should show a percentage and appear on EPA's list. EPA's example of the disease-claim limit: a label may say "controls ticks" but not "controls ticks that carry Lyme disease." A label claiming the product is recommended by EPA is misleading, EPA says, because EPA does not review exempted products. [EPA](https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents) also says it is not simple to determine the status of products in many cases, that illegal products exist that neither qualify for the exemption nor are registered, and that a product missing any exemption criterion is not exempt, so selling it without registration may violate FIFRA. Once both products in your hands carry a number, the question is which; our [picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet) comparison takes that one. ### Is pure lemon eucalyptus essential oil the same thing? No. The essential oil in the dropper bottle is not the registered repellent. [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) does not recommend using "pure" oil of lemon eucalyptus, the essential oil that is not formulated, as a repellent, because it has not undergone validated testing for safety and efficacy and is not registered with EPA as an insect repellent. The caution runs wider than one oil: the health risks and efficacy of essential oils have not been as widely studied as common insect repellents. ### What does the minimum-risk exemption actually mean? A natural repellent on the shelf may not be registered at all. Unregistered products are sold under an exemption: [EPA](https://www.epa.gov/minimum-risk-pesticides/minimum-risk-pesticide-definition-and-product-confirmation) has exempted certain minimum risk pesticides from registration under the federal pesticide law because it determined they pose little to no risk to human health or the environment, a provision found in 40 CFR 152.25(f). In the 1990s, EPA evaluated the active ingredients in these unregistered products for safety and determined they posed minimal risk to human health at the percentages found in products on the market. But in EPA's own words, "products made from these ingredients have not been evaluated for effectiveness." Safety was reviewed. Effectiveness was not. EPA's examples of ingredients used in unregistered exempt repellents include citronella oil, cedar oil, geranium oil, peppermint and peppermint oil, and soybean oil. The exemption also carries a limit: minimum risk labels may not link the pests they claim to control with any specific disease. The claim may only be for the pest as a pest, not as a disease vector. This gap has EPA's attention. After analyzing public comments, the agency concluded that public health products must be supported by evidence that they are effective against the target pest, and it is considering a proposal to remove personal mosquito and tick repellents from the minimum risk exemption. Once removed, those repellents would need EPA registration before sale in the United States. ### What is citronella's actual track record? Citronella has a long paper trail. Oil of citronella is a naturally occurring insect and animal repellent distilled from two grass varieties; its main components are citronellol, citronellal, and geraniol. It was first registered in the United States in 1948 and currently sits on EPA's list of minimum risk pesticides, so it sits in both camps: 3 EPA-registered products use it, and so do exempt products. It repels pests rather than killing them. It works by masking scents that are attractive to insects, making it difficult for them to locate a target to feed. Natural does not mean nothing to watch: oil of citronella can be mildly irritating to the skin and eyes and may cause skin allergies for some people with prolonged or frequent exposure. We dig deeper in our post on [citronella and plant repellents](https://longsleeve.com/blog/citronella-and-plant-repellents). ### What have studies found about natural repellents? The honest answer is mixed, and the details matter. In a 2017 laboratory study in the Journal of Insect Science, spray-on repellents containing DEET and PMD had the highest efficacy in repelling Aedes aegypti mosquitoes compared with repellents containing other ingredients. The natural-positive result inside that finding: in the study's attraction assays, products containing 30 percent PMD (oil of lemon eucalyptus) or 98 percent DEET produced equally strong reductions in mosquito attraction. A plant-derived registered active matched 98 percent DEET in that laboratory setup, against that species. The same study was rougher on gadgets. Of five wearable repellent devices tested, only the one releasing metofluthrin significantly reduced the number of attracted mosquitoes, and a citronella candle had no effect. None of the repellent bracelets tested caused a significant reduction in mosquito attraction; the authors hypothesize the concentrations emitted were too low to have an effect. The authors concluded that many of the products they tested that were marketed as repellents do not reduce mosquito attraction to humans. A 2020 laboratory study in the Journal of Medical Entomology looked specifically at exempt ingredients and found measurable effects: cinnamon oil, peppermint oil, spearmint oil, lemongrass oil, and garlic oil reduced mosquito attraction to human odor. Of five commercial repellent sprays tested, only one reduced mosquito attraction, for up to 30 minutes in that assay. The shape of the result: several oils showed effects while most finished products did not. And no EPA-registered repellents contain garlic oil, rosemary, lemongrass, thyme, or geraniol oils as active ingredients. Duration is where botanicals struggled most in a 2002 laboratory study in the New England Journal of Medicine. In that study, a formulation containing 23.8 percent DEET had a mean complete-protection time of 301.5 minutes, a soybean-oil-based repellent protected against mosquito bites for an average of 94.6 minutes, and all other botanical repellents tested provided protection for a mean duration of less than 20 minutes. Repellent-impregnated wristbands offered no protection in that study. The CDC Yellow Book is blunt on gadgets: ingesting vitamin B or garlic and wearing sound-emitting devices or repellent-impregnated wristbands are ineffective. We take apart sound-emitting devices in our [ultrasonic repellers](https://longsleeve.com/blog/ultrasonic-repellers) post. ### How do you read a repellent label? Look for an EPA registration number (EPA Reg. No.). It means the company provided EPA with technical information on the effectiveness of the product. EPA registration of skin-applied repellent products indicates they have been evaluated and approved for human safety and effectiveness when applied according to label instructions, and per CDC, EPA-registered products are considered safe when used as directed, even for pregnant and breastfeeding women. Repellents without a registration number have not been evaluated by EPA, and EPA cannot advise consumers about their effectiveness. CDC states that the effectiveness of non-EPA registered insect repellents, including some natural repellents, is not known, and the CDC Yellow Book advises travelers to avoid them for that reason. To protect against germs spread by mosquitoes, CDC and EPA recommend using an EPA-registered insect repellent. Concentration matters too. In general, higher concentrations of active ingredient provide longer protection regardless of which active it is, and products with under 10 percent active ingredient might offer only limited protection. EPA also notes that registration testing follows scientific guidelines and approved study methods, yet protection times vary because of differences in testing conditions. Where does our own product sit? Not in the natural aisle. Picaridin is one of the two actives EPA characterizes as conventional repellents. Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance free, with nine disclosed ingredients. Weighing the registered actives against each other? Our [picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet) comparison lays out the evidence. ### FAQ **Can you use natural repellents on babies and kids?** Age rules differ by ingredient. The American Academy of Pediatrics does not recommend insect repellents for children younger than two months. CDC says not to use products containing OLE or PMD on children under 3 years old. Per the CDC Yellow Book, repellents containing DEET, picaridin, IR3535, and 2-undecanone can be used on children without age restriction. Some oil of citronella products should not be used on children less than six months old unless directed by a doctor; that information is listed on the product label. Ask your pediatrician what fits your child. **Is oil of lemon eucalyptus natural?** It is plant-derived but not raw. NPIC explains that oil of lemon eucalyptus is based on chemicals that occur in nature but is a man-made ingredient, and PMD is the synthesized version of OLE. CDC does not recommend the pure, unformulated essential oil as a repellent because it has not undergone validated testing for safety and efficacy and is not registered with EPA. **Do citronella candles keep mosquitoes away?** In a 2017 Journal of Insect Science laboratory study, a citronella candle had no effect on the number of mosquitoes attracted. Oil of citronella itself works by masking scents that are attractive to insects, and it appears in 3 EPA-registered products as well as exempt ones, so the ingredient and the candle format are separate questions. **Why can a repellent be sold if its effectiveness was never tested?** Because of the minimum risk exemption in 40 CFR 152.25(f). EPA evaluated the exempt active ingredients for safety in the 1990s and found minimal risk at marketed percentages, but products made from these ingredients have not been evaluated for effectiveness. EPA is now considering a proposal to remove personal mosquito and tick repellents from the exemption, which would require registration before sale. **What is the difference between a natural repellent and a regular one?** Registration, not the source of the ingredient. EPA says insect repellents are pesticides, defined under pesticide law as any substance intended for preventing, destroying, repelling or mitigating any pest, and that its evaluation for registration includes assuring the product does not pose risks to vulnerable populations, including children and pregnant women. A product sold under the minimum risk exemption did not get that review: EPA does not review exempted products. The California Department of Public Health adds that the CDC strongly suggests using repellents with ingredients registered by EPA. **Are plant-based bug spray ingredients evaluated for safety?** The ingredient may have been; the product in your hand may not have been. For a registered product, EPA says it must have safety and effectiveness data, which EPA evaluates before allowing it on the market. For an exempt one, EPA says it evaluated the exempt active ingredients for safety in the 1990s and found minimal risk at marketed percentages, but products made from those ingredients have not been evaluated for effectiveness; EPA generally does not review products that claim the exemption or their labels, and the producer is responsible for evaluating whether the product meets the criteria. Oil of lemon eucalyptus, which the California Department of Public Health calls naturally derived from the lemon eucalyptus plant, is a registered active, so the EPA Reg. No. on the label, not the word natural, tells you which case you are holding. ### Related reading - [Do Citronella Candles Work?](https://longsleeve.com/blog/citronella-and-plant-repellents) Evidence on plant-based repellents. - [Picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet). Duration, kids, ticks, and materials. - [DEET Safety](https://longsleeve.com/blog/deet-safety-evidence). EPA reviews, CDC guidance, kids, and common questions. - [Mosquito Repellent Candles](https://longsleeve.com/blog/mosquito-repellent-candles). What they can and cannot do. More Longsleeve in your Google feed: ### Sources 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods: [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. CDC, Preventing Mosquito Bites: [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC, Preventing Tick Bites: [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. EPA, Skin-Applied Repellent Ingredients: [https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients) 1. EPA, Regulation of Skin-Applied Repellents: [https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents](https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents) 1. EPA, Minimum Risk Pesticide Definition and Product Confirmation: [https://www.epa.gov/minimum-risk-pesticides/minimum-risk-pesticide-definition-and-product-confirmation](https://www.epa.gov/minimum-risk-pesticides/minimum-risk-pesticide-definition-and-product-confirmation) 1. EPA, Conditions for Minimum Risk Pesticides: [https://www.epa.gov/minimum-risk-pesticides/conditions-minimum-risk-pesticides](https://www.epa.gov/minimum-risk-pesticides/conditions-minimum-risk-pesticides) 1. EPA, Personal Insect Repellents and Minimum Risk Pesticides: [https://www.epa.gov/minimum-risk-pesticides/personal-insect-repellents-and-minimum-risk-pesticides](https://www.epa.gov/minimum-risk-pesticides/personal-insect-repellents-and-minimum-risk-pesticides) 1. EPA, Find the Repellent that is Right for You: [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. NPIC, Insect Repellents Fact Sheet: [https://npic.orst.edu/factsheets/repellents.html](https://npic.orst.edu/factsheets/repellents.html) 1. NPIC, Oil of Citronella General Fact Sheet: [https://npic.orst.edu/factsheets/citronellagen.html](https://npic.orst.edu/factsheets/citronellagen.html) 1. Journal of Insect Science, 2017, laboratory study of commercial repellent products and devices: [https://pmc.ncbi.nlm.nih.gov/articles/PMC5388317/](https://pmc.ncbi.nlm.nih.gov/articles/PMC5388317/) 1. New England Journal of Medicine, 2002, laboratory study of repellent protection times: [https://pubmed.ncbi.nlm.nih.gov/12097535/](https://pubmed.ncbi.nlm.nih.gov/12097535/) 1. Journal of Medical Entomology, 2020, laboratory study of exempt repellent ingredients: [https://pubmed.ncbi.nlm.nih.gov/31612914/](https://pubmed.ncbi.nlm.nih.gov/31612914/) 1. California Department of Public Health, EPA-Registered Repellent Ingredients. [https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/EPA-Registered-Repellent-Ingredients.aspx](https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/EPA-Registered-Repellent-Ingredients.aspx) 1. EPA, What is an Insect Repellent?, last updated July 6, 2026. [https://www.epa.gov/insect-repellents/what-insect-repellent](https://www.epa.gov/insect-repellents/what-insect-repellent) 1. EPA, Active Ingredients Allowed in Minimum Risk Pesticide Products, last updated August 10, 2026. [https://www.epa.gov/minimum-risk-pesticides/active-ingredients-allowed-minimum-risk-pesticide-products](https://www.epa.gov/minimum-risk-pesticides/active-ingredients-allowed-minimum-risk-pesticide-products) Last reviewed 2026-08-17 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Cutter Lemon Eucalyptus Insect Repellent](https://longsleeve.com/repellent-index/cutter-lemon-eucalyptus-insect-repellent), [OFF! Botanicals Insect Repellent I](https://longsleeve.com/repellent-index/off-botanicals-insect-repellent-i), or [Refined Oil Of Nepeta Cataria 15% Lotion](https://longsleeve.com/repellent-index/refined-oil-of-nepeta-cataria-15-lotion). ## Why No-See-Um Bites Itch So Much, and How to Treat Them URL: https://longsleeve.com/blog/no-see-um-bites > No-see-um bites itch because the midge cuts the skin and leaves saliva in the wound. What causes the itch, how long bites last, and how to treat them. Source: https://longsleeve.com/blog/no-see-um-bites By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 26, 2026 · Updated September 3, 2026 **Short answer:** A 2018 paper in Parasites and Vectors describes the midge as a pool feeder: it cuts the skin, feeds from a small pool of blood, and leaves saliva in the wound. In more than 90 percent of people, the immune system becomes sensitized to those saliva proteins, and the itch is that hypersensitivity reaction. ### Why are no-see-um bites so itchy? No-see-um bites itch because of how the insect feeds and what it leaves behind. No-see-ums are biting midges; the CDC uses both names for the same insect. A mosquito feeds from a blood vessel. A Culicoides biting midge is a pool feeder: a 2018 paper in Parasites and Vectors describes its mouthparts piercing the outer skin and doing significant mechanical damage to the dermis beneath, so that blood collects in a little pool it drinks from. Its saliva goes into that wound carrying, per the same paper, anti-hemostatic factors, protease inhibitors, and immune modulatory proteins. Your body notices. A 2020 review in Allergologie Select reports that bites from blood-feeding insects routinely sensitize people to salivary proteins and cause local hypersensitivity reactions in more than 90 percent of the population. The CDC puts it simply for mosquitoes: the insect injects saliva as it feeds, your body reacts, and you get a bump and itching. The itch is your immune system answering a foreign protein. The review also notes that midge species feeding on humans can cause type 1 and type 4 hypersensitivity reactions in the skin, and it describes bites taking more than one form: the fast welt and the slower, harder bump. ### Why do no-see-um bites show up days later? Because a bite can produce a late reaction as well as an immediate one, and the late one develops 12 to 24 hours after the bite and then persists for several days, according to a 2020 review in Allergologie Select. The Allergologie Select review describes both: in most people a bite causes either an immediate reaction, wheals, redness and itching within minutes, or a late reaction, a firm papule that develops 12 to 24 hours after the bite and persists for several days. The late reaction is what fools people. You spend Saturday on the sand, notice almost nothing, and wake up Sunday with a crop of hard, itchy bumps. The review reports these as the two patterns most people get, one or the other, and it notes separately that midge species feeding on humans can cause both type 1 and type 4 hypersensitivity reactions in the skin. ### How long do no-see-um bites last? The late-reaction bump persists for several days, according to the Allergologie Select review; the immediate welt is transient and fades sooner. The outer bound is one unusual case. A 2010 case report in the American Journal of Tropical Medicine and Hygiene, titled Bullous Leg Lesions Caused by Culicoides Midges after Travel in the Amazon Basin, describes lesions that stabilized by the third day and had largely resolved by 14 days with minimal scarring. That was a severe blistering reaction, covered below, and no forecast for a typical bite. Why do two people heal so differently? The CDC's note on mosquito bites applies: some people have only a mild reaction, others a large area of swelling, soreness and redness. The person matters as much as the insect. ### What is the fastest way to treat no-see-um bites? Wash it, ice it, and keep your hands off it. The CDC's bite-care protocol is written for mosquito bites and is the sensible place to start for a midge bite: 1. Wash the bite and the surrounding area with soap and water. 1. Apply an ice pack for 10 minutes to reduce swelling and itching. Reapply as needed. 1. Apply a baking soda and water paste, which the CDC says can help reduce the itch response. 1. Use an over-the-counter anti-itch or antihistamine cream, following the label directions. 1. Do not scratch. Scratched bites can become infected. If you want a natural treatment, ice and a baking soda paste are the ones with a public health agency behind them. Our [mosquito bite treatment guide](https://longsleeve.com/blog/mosquito-bite-treatment) goes deeper. Then watch the bite. The CDC says an infected bite may look red, feel warm, or show a red streak spreading outward. If symptoms worsen, see a healthcare provider. ### No-see-um bites vs mosquito bites: how to tell Judge by the insect and the setting; the bumps themselves overlap, since the Allergologie Select review describes the immediate welt and delayed papule for blood-feeding insect bites generally. Not sure what bit you? Our [black fly bites](https://longsleeve.com/blog/black-fly-bites) and [chigger bites](https://longsleeve.com/blog/chigger-bites) guides cover two other suspects. | Attribute | No-see-um (biting midge) | Mosquito | |---|---|---| | How it feeds | Pool feeder: mouthparts pierce the epidermis and damage vessels in the dermis; it feeds from the pool of blood that forms (Parasites and Vectors, 2018) | Feeds from a blood vessel (Parasites and Vectors, 2018) | | Size | No more than 1/32 of an inch (Illinois DPH); about 1 mm and noiseless (Am J Trop Med Hyg, 2010); usually under an eighth of an inch, 3 mm (CDC) | Not addressed by our sources | | Window screens | Crawls through most screens that otherwise keep out mosquitoes (CDC) | Kept out by most screens (CDC) | | Bed nets | Standard bed nets are less effective; the insects pass through the netting (WHO) | Not addressed by our sources | | Time of day | Day or night (Illinois DPH); timing varies by species (CDC) | Day and night (CDC) | | Reaction timing | Immediate wheal within minutes, or a firm papule 12 to 24 hours later lasting several days (Allergologie Select, 2020, on insect bites generally) | Same two patterns | Bitten indoors, behind screens, no mosquito in sight? Suspect a midge. ### Do no-see-ums come through window screens? Yes. The [CDC](https://www.cdc.gov/oropouche/stories/midges-under-the-microscope.html) states that because of their small size, biting midges can crawl through most screens that otherwise keep out mosquitoes, which explains waking up bitten with no bug in sight. The fix has a number. The [CDC](https://www.cdc.gov/oropouche/prevention/index.html)'s Oropouche prevention page says many common window and door screens do not have holes small enough to stop biting midges and recommends 20x20 mesh. Illinois DPH agrees: standard household screen mesh is not fine enough for the tiniest biting flies and should be replaced with finer mesh where they are a problem. Bed nets share the weakness: the World Health Organization notes standard nets are less effective against biting midges, which pass through the netting, while fine mesh nets and residual insecticide sprayed on the walls of infested buildings have been shown to be effective. ### Do no-see-um bites blister? Blistering is documented but unusual, and not what to expect. The clearest account is a 2010 case report in the American Journal of Tropical Medicine and Hygiene, Bullous Leg Lesions Caused by Culicoides Midges after Travel in the Amazon Basin: multiple blisters up to 4.5 cm across developed on the legs, with swelling around them. The lesions stabilized by the third day and had largely resolved by 14 days with minimal scarring. The mechanism is the ordinary one at full volume: midge species that feed on humans can cause type 1 and type 4 hypersensitivity reactions in the skin, per the Allergologie Select review. The Illinois Department of Public Health, writing about biting flies as a group and not midges specifically, warns that in sensitive individuals the fly's saliva can trigger life-threatening allergic reactions. The CDC's infection signs apply: redness, warmth, or a red streak spreading outward. See a healthcare provider if symptoms worsen. ### Where are no-see-ums found? Near water, in damp ground, and, on the Illinois Department of Public Health's own pest pages, in Illinois. The Illinois Department of Public Health calls biting midges serious pests along the shores of oceans, lakes, ponds and rivers, biting day or night. Their larvae live in moist sand or soil, rotting vegetation, tree holes and other damp spots, often at the edges of ponds, marshes and lagoons. The state's structural pest control page treats midges as a household problem, down to replacing window screens with finer mesh. The CDC adds that a midge species that could carry Oropouche virus lives in the eastern United States. The name fits: the 2010 case report calls Culicoides midges approximately 1 mm and noiseless, easy to overlook, and the CDC says they can be out at different times of day, varying by species. Beach bites have another common suspect, covered in our [sand flea bites](https://longsleeve.com/blog/sand-flea-bites) guide. For identification and biology, start with our [guide to no-see-ums](https://longsleeve.com/blog/no-see-ums). ### Can no-see-ums make you sick? They can carry a virus, and the CDC reports no local transmission in the United States. The CDC says Oropouche virus is spread mostly by tiny biting midges, also called no-see-ums, though some mosquitoes can spread it as well. Common symptoms, per the [CDC](https://www.cdc.gov/oropouche/symptoms/index.html), are fever, severe headache, chills, muscle aches and joint pains, typically lasting 2 to 7 days but often reoccurring later. Two CDC facts frame the risk at home: a midge species that could carry the virus lives in the eastern United States, and cases have been found in travelers returning to the United States, with no local transmission. If you develop a fever, severe headache or joint pain after a trip where midges bit you, call a clinician and tell them what bit you. ### How do you keep no-see-ums from biting? Use a repellent labeled for biting midges, cover up, move the air, and fix the screens. **Repellent.** The CDC advises EPA-registered repellents labeled for flies, biting flies, or Culicoides, the genus covering biting midges, punkies, granny nippers and no-see-ums. The Illinois Department of Public Health adds a caveat: repellents effective against mosquitoes have been found less effective against some types of biting flies, and it names DEET or picaridin as the best active ingredients. Our [guide to no-see-um repellents](https://longsleeve.com/blog/no-see-um-repellent) goes deeper. **Clothing.** The CDC says loose-fitting, long-sleeved shirts and pants. Illinois DPH goes further for biting flies: heavy-duty, light-colored clothing, including long-sleeve shirts, long pants and hats. **Air and screens.** The CDC suggests fans outdoors to blow biting midges away, and 20x20 mesh indoors, since many common screens have holes too large to stop them. **The label.** The [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively)'s rule for every repellent: always read the product label before using it. That is where a product's covered pests and claimed hours live. ### Common questions **How do you get rid of no-see-um bites fast?** Start with the CDC 's bite-care steps: wash the bite and the surrounding skin with soap and water, hold an ice pack on it for 10 minutes to reduce swelling and itching, and use an over-the-counter anti-itch or antihistamine cream as the label directs. Then leave it alone. The CDC's warning is that scratched bites can become infected. **How long does a no-see-um bite last?** The delayed reaction, a firm bump that appears 12 to 24 hours after the bite, persists for several days, according to a 2020 review in Allergologie Select. The longest documented course we found is a single severe case in the American Journal of Tropical Medicine and Hygiene, where blistering lesions had largely resolved by 14 days. That was one unusual case, and the outer edge of what has been documented. **Why am I waking up with bites but no bugs?** Probably because biting midges got in and you never saw them. The CDC says they are small enough to crawl through most screens that otherwise keep out mosquitoes. A 2010 case report describes them as roughly 1 mm long and noiseless, so they are easy to miss. The CDC recommends 20x20 mesh screens to keep them out of the house. **Are no-see-um bites worse than mosquito bites?** No source we use ranks them, so we will not either. What is documented is a difference in how they feed. A 2018 paper in Parasites and Vectors describes mosquitoes as vessel feeders and Culicoides midges as pool feeders whose mouthparts damage the dermis and leave small pools of blood under the skin. The reaction patterns, an immediate welt or a delayed hard bump, apply to insect bites generally. **Can no-see-ums make you sick?** The CDC says biting midges can spread Oropouche virus. Common symptoms are fever, severe headache, chills, muscle aches and joint pains, typically lasting 2 to 7 days and often reoccurring later. The CDC has found cases in travelers returning to the United States and reports no cases of local transmission. If you get a fever after midge bites on a trip, see a clinician. ### About Longsleeve Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours, and its accepted federal label carries the claim "Repels biting flies, stable flies, black flies, gnats, chiggers, sand flies and Scottish biting midges (no see-ums) for up to 8 hours." It is fragrance-free, with nine disclosed ingredients. Of the 631 EPA-registered skin repellents in [our Repellent Index](https://longsleeve.com/repellent-index), 47 carry a stated no-see-um protection time you can read off their federal label. None of this is medical advice. If you develop a rash or a fever after a bite, call your doctor and tell them what bit you. ### Related reading - [No-see-ums: identification and biology](https://longsleeve.com/blog/no-see-ums). The hub for what they are and where they breed. - [No-see-um repellent](https://longsleeve.com/blog/no-see-um-repellent). For the reader who has decided to buy something and wants to read labels first. - [Mosquito Bite Treatment: Itch Relief, Swelling, Infection Signs, and When to Seek Care](https://longsleeve.com/blog/mosquito-bite-treatment). The same CDC protocol, in more depth. - [Black Fly Bites: Swelling, Bleeding, Treatment, and Prevention](https://longsleeve.com/blog/black-fly-bites). The other biting fly on the Illinois DPH page, and a common misidentification. - [Sand Flea Bites: Midges, Sand Flies, True Fleas, and Treatment](https://longsleeve.com/blog/sand-flea-bites). The main beach-bite differential. - [Chigger Bites: Treatment, Itch, Myths, and Prevention](https://longsleeve.com/blog/chigger-bites). Another small biter whose bites cluster and itch. - [Facts and label claims](https://longsleeve.com/facts). The claims and ingredient transparency page. More Longsleeve in your Google feed: ### Sources 1. Parasites and Vectors, 2018, peer-reviewed article on Culicoides biting midges (PubMed Central PMC6011595). [https://pmc.ncbi.nlm.nih.gov/articles/PMC6011595/](https://pmc.ncbi.nlm.nih.gov/articles/PMC6011595/) 1. Allergologie Select, 2020, peer-reviewed review of insect bite hypersensitivity (PubMed Central PMC7709451). [https://pmc.ncbi.nlm.nih.gov/articles/PMC7709451/](https://pmc.ncbi.nlm.nih.gov/articles/PMC7709451/) 1. CDC, Midges Under the Microscope (Oropouche). [https://www.cdc.gov/oropouche/stories/midges-under-the-microscope.html](https://www.cdc.gov/oropouche/stories/midges-under-the-microscope.html) 1. CDC, About Mosquito Bites. [https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html](https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html) 1. American Journal of Tropical Medicine and Hygiene, 2010, 83(3), case report on Culicoides bites (PubMed Central PMC2929031). [https://pmc.ncbi.nlm.nih.gov/articles/PMC2929031/](https://pmc.ncbi.nlm.nih.gov/articles/PMC2929031/) 1. Illinois Department of Public Health, Biting Flies. [https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html](https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html) 1. CDC, Meet the Midge (Oropouche). [https://www.cdc.gov/oropouche/stories/meet-the-midge.html](https://www.cdc.gov/oropouche/stories/meet-the-midge.html) 1. World Health Organization, Oropouche virus disease fact sheet. [https://www.who.int/news-room/fact-sheets/detail/oropouche-virus-disease](https://www.who.int/news-room/fact-sheets/detail/oropouche-virus-disease) 1. CDC, About Mosquitoes. [https://www.cdc.gov/mosquitoes/about/index.html](https://www.cdc.gov/mosquitoes/about/index.html) 1. CDC, Oropouche: Prevention. [https://www.cdc.gov/oropouche/prevention/index.html](https://www.cdc.gov/oropouche/prevention/index.html) 1. CDC, Oropouche: Symptoms. [https://www.cdc.gov/oropouche/symptoms/index.html](https://www.cdc.gov/oropouche/symptoms/index.html) 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) Last reviewed 2026-09-03 · every claim on this page is sourced above ## No-See-Um Repellent: Check the Label for Biting Midges URL: https://longsleeve.com/blog/no-see-um-repellent > How to choose no-see-um repellent by label, including CDC guidance for EPA-registered products labeled for flies, biting flies, or Culicoides, plus screens and fans. Source: https://longsleeve.com/blog/no-see-um-repellent By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 26, 2026 The CDC's advice for no-see-ums is specific: use an EPA-registered repellent whose label lists flies, biting flies, or Culicoides. Most repellent labels only state mosquito and tick claims, so check the label itself. Of 631 EPA-registered skin repellents, 47 carry a stated no-see-um protection time. Most repellent shopping advice is written for mosquitoes. No-see-ums, the biting midges that ruin beach evenings and lakeside porches, are a different insect with their own line on a repellent label, and most products never mention them. This is how to pick one that does, and what to do alongside it, using only what the CDC, EPA, and state health departments actually say. ### What does the CDC say to look for? One sentence does most of the work. The [CDC](https://www.cdc.gov/oropouche/prevention/index.html), writing about preventing bites from the midges that spread Oropouche virus, says: "Look for EPA-registered repellents labeled for flies, biting flies, or *Culicoides* (biting midges, punkies, granny nippers, and no-see-ums)." Culicoides is the genus of biting midge, and it is the word a label uses when the manufacturer has registered a claim against them. **Short answer:** For no-see-um repellent, the CDC says to look for an EPA-registered repellent labeled for flies, biting flies, or *Culicoides*. A mosquito claim alone does not prove a biting-midge claim. Check the product label, follow the directions, and pair repellent with loose long sleeves and pants, 20x20 mesh screens, and outdoor fans. There is also a reason beyond comfort to take midges seriously. Biting midges are the primary spreaders of Oropouche virus, and the CDC states plainly that there are no vaccines to prevent it and no medicines to treat it: “The best way to protect yourself from Oropouche is to prevent bug bites.” For this insect, prevention is the whole menu. ### Why isn't "repels mosquitoes" enough? Because a repellent label is a registered document, and claims on it are pest by pest. A product registered for mosquitoes and ticks has told EPA nothing about biting midges. Even EPA's own consumer search tool reflects this: it lets you filter by mosquitoes, ticks or both, protection time, and active ingredient, and midges are not one of the filters. [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively)'s standing instruction covers the gap: "always read the product label before using the product." For no-see-ums, the label is the only place the answer lives. Because EPA's tool cannot answer the midge question, we built something that can. [The Repellent Index](https://longsleeve.com/repellent-index) holds every EPA-registered skin-applied repellent, 631 products, with the pest claims we could read off each product's federal label. Of those 631, 47 carry a stated no-see-um protection time. The [full statistics](https://longsleeve.com/repellent-index/statistics) are free, and so is the dataset. ### Which active ingredients are recommended? For biting flies as a group, the Illinois Department of Public Health names two: repellents "containing the active ingredient DEET (N,N-diethyl-meta-toluamide) or picaridin are best." On picaridin specifically, the National Pesticide Information Center notes it "can be used on human skin or clothing to repel mosquitoes, biting flies, ticks, fleas, and chiggers," and that it is a synthetic compound made to resemble piperine, found in the group of plants used to produce black pepper. Illinois DPH also says the honest thing most marketing leaves out: repellents, while effective against mosquitoes, "have been found to be less effective against some types of biting flies," and should be supplemented with other preventive methods, like avoiding the areas the flies inhabit and their peak biting times. A repellent with a midge claim on its label is the right tool. It is still one tool. ### How do you apply repellent so it actually works? EPA's application rules, from its guidance on using repellents safely and effectively: - **Read and follow the label directions,** and be sure you understand how much to apply. - **Apply only to exposed skin and/or clothing.** Do not use under clothing. - **Keep it away from eyes and mouth,** apply sparingly around ears, and with sprays, apply to hands first and then to the face. - **Never apply over cuts, wounds, or irritated skin.** - **For children:** do not apply to children's hands. Apply to your own hands first, then put it on the child. - **Afterward:** wash treated skin and clothes with soap and water once you are back indoors. ### What works alongside repellent? Three things, all from the CDC's midge guidance: - **Clothing.** Wear loose-fitting, long-sleeved shirts and pants. - **Better screens.** Many common window and door screens do not have holes small enough to stop biting midges. The CDC's recommendation is 20x20 mesh. - **A fan.** The CDC suggests using fans outdoors to help blow biting midges away. Illinois DPH agrees: fans can keep small areas free of the smaller flies, whose flight is affected by air currents. Timing is harder to game than it is for mosquitoes. A CDC entomologist notes there is no single biting hour: biting midges can be out at different times of day, and the time varies among species. And if you are hoping the county will handle it, the [CDC](https://www.cdc.gov/oropouche/stories/midges-under-the-microscope.html) is frank that less is known about controlling biting midges in the community than about controlling mosquitoes. The tools you control, label-checked repellent, clothing, screens, and moving air, are most of the game. Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours, and its accepted federal label carries the claim "Repels biting flies, stable flies, black flies, gnats, chiggers, sand flies and Scottish biting midges (no see-ums) for up to 8 hours." It is fragrance-free, with nine disclosed ingredients. ### Short answers **What is the best repellent for no-see-ums?** The CDC does not rank products. Its guidance is to use an EPA-registered repellent whose label lists flies, biting flies, or Culicoides. Illinois DPH points to DEET and picaridin as the actives to look for against biting flies. From there, compare the labels: 47 of the 631 registered skin repellents state a no-see-um protection time. **Does DEET work on no-see-ums?** Illinois DPH names DEET, along with picaridin, as the actives to look for against biting flies, while cautioning that repellents can be less effective against some biting flies than against mosquitoes. Check the individual product label for a midge or biting-fly claim. **Why do no-see-ums get through my window screens?** Standard mesh is too coarse. The CDC says many commonly used window and door screens do not have holes small enough to stop biting midges, and recommends 20x20 mesh screens. **Do fans really keep no-see-ums away?** The CDC recommends using fans outdoors to help blow biting midges away, and Illinois DPH notes fans can keep small areas free of smaller flies because their flight is affected by air currents. Weak fliers, moving air. It is the cheapest tool on this page. **What time of day do no-see-ums bite?** There is no single answer. Per a CDC entomologist, biting midges can be active at different times of day, and the timing varies among species. Assume any calm hour near water can be a biting hour. More on this insect: [No-See-Ums: what they are and what repels them](https://longsleeve.com/blog/no-see-ums), and [what their bites look like and how to treat them](https://longsleeve.com/blog/no-see-um-bites). ### Related reading - [No-See-Ums](https://longsleeve.com/blog/no-see-ums). What they are and what repels them. - [No-See-Um Bites](https://longsleeve.com/blog/no-see-um-bites). Why they itch, how long they last, and how to treat them. - [Gnat Repellent](https://longsleeve.com/blog/gnat-repellent). Biting midges, labels, screens, and fans. - [Sand Flea Bites](https://longsleeve.com/blog/sand-flea-bites). Midges, sand flies, true fleas, and treatment. More Longsleeve in your Google feed: ### Sources 1. CDC, Preventing Oropouche. [https://www.cdc.gov/oropouche/prevention/index.html](https://www.cdc.gov/oropouche/prevention/index.html) 1. CDC, Oropouche Puts Biting Midges Under the Microscope. [https://www.cdc.gov/oropouche/stories/midges-under-the-microscope.html](https://www.cdc.gov/oropouche/stories/midges-under-the-microscope.html) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. NPIC, Picaridin General Fact Sheet. [https://npic.orst.edu/factsheets/PicaridinGen.html](https://npic.orst.edu/factsheets/PicaridinGen.html) 1. Illinois Department of Public Health, Biting Flies. [https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html](https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html) Last reviewed 2026-08-26 · every claim on this page is sourced above ## No-See-Ums: What They Are and What Repels Them URL: https://longsleeve.com/blog/no-see-ums > What no-see-ums are, why biting midges get through screens, when they bite, what their bites mean, and how to choose an EPA-registered repellent labeled for them. Source: https://longsleeve.com/blog/no-see-ums By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 24, 2026 No-see-ums are biting midges, tiny flies in the family Ceratopogonidae. Most are between 1 and 2.5 millimeters long, small enough to pass through ordinary window screens. The females bite because they need a protein meal to make eggs. The CDC's advice is an EPA-registered repellent whose label names flies, biting flies, or *Culicoides*. ### What exactly is a no-see-um? It is a fly. The insects people call no-see-ums are biting midges, and the CDC treats the two names as the same thing, describing Oropouche virus as spread mostly by "tiny biting midges, sometimes called 'no-see-ums.'" Depending where you are standing, you may hear punkies, granny nippers, sand flies, or simply gnats. **Short answer:** No-see-ums are biting midges, tiny flies in the family Ceratopogonidae. Many are only 1 to 2.5 millimeters long, small enough to pass through ordinary window screens. CDC guidance says to look for EPA-registered repellents labeled for flies, biting flies, or *Culicoides*, and to pair repellent with long sleeves, pants, air conditioning, better screens, or fans. ### Why can I feel the bite but not see the insect? Because they are roughly the size of a grain of coarse pepper. The same review puts it plainly: biting midges are "tiny culicomorph insects, usually measuring 1 to 2.5 mm in length." A mosquito is several times larger and announces itself. A midge does not. Size is also why the usual defenses fail. The [CDC](https://www.cdc.gov/oropouche/stories/midges-under-the-microscope.html) is direct about this: "Because of their small size, biting midges can crawl through most screens that otherwise keep out mosquitoes." A porch screen sized for mosquitoes is, to a no-see-um, an open door. ### Why do the bites itch so much for something so small? Only the females bite, and they are not feeding for themselves. In *Culicoides* and related genera "the females usually need a proteinaceous meal to produce eggs." The bite is a means to reproduction, which is why swatting one insect rarely ends the problem: you are standing where they breed. ### Where do they come from? Wet ground, broadly defined. Their larvae "develop in all types of aquatic, semiaquatic and terrestrial humid habitats, with many species using the entire range of these." That covers salt marsh, pond margin, damp sand, mud, and the soggy corner of a lawn. It is why coastal holidays and lakeside evenings have a reputation, and why there is no single container to tip out the way there is with mosquitoes. ### What time of day do no-see-ums bite? There is no reliable answer, and that is the useful thing to know. CDC medical entomologist Roxanne Connelly puts it this way: "Biting midges can be out and around at different times of day, the time varies among different species." Dawn and dusk are a common experience, but planning your evening around a fixed window is not a strategy. Community-level control is also thinner than it is for mosquitoes. The CDC notes that "there's less known about controlling biting midges in the community." Which pushes the problem back to what you personally put on. ### Do no-see-ums spread disease? Some biting midges carry viruses. The reason the CDC has been writing about them recently is Oropouche virus, and the agency reports that "a biting midge species that could carry the virus lives in the eastern United States." That is a statement about the insect's range, not a forecast, and most no-see-um encounters in the United States are [an itching problem](https://longsleeve.com/blog/no-see-um-bites) rather than an illness one. If you develop fever, joint pain, or body aches after travel, that is a conversation for a clinician, not a web page. ### Does spraying the yard get rid of them? Not reliably, and the reason is timing and location rather than the chemistry. The CDC notes that "chemicals used to spray for mosquitoes in the community will also kill biting midges, but those are typically used when mosquitoes are most active." Midges do not necessarily keep mosquito hours. There is also an open question about whether treatment reaches them at all. As Connelly puts it: "We know the equipment and products used to control mosquitoes will also work on biting midges. But what's not been evaluated is how effective the products are in getting to where the biting midges are." For now, what you wear and what you put on your skin is the part you control. ### What actually repels no-see-ums? The [CDC](https://www.cdc.gov/oropouche/prevention/index.html)'s guidance is specific, and the specificity is the point: "Look for EPA-registered repellents labeled for flies, biting flies, or *Culicoides* (biting midges, punkies, granny nippers, and no-see-ums)." A product that only names mosquitoes and ticks has not been evaluated against midges. The label is the evidence. The CDC adds that "when used as directed, EPA-registered insect repellents are proven safe and effective," and pairs repellent with two physical measures: "wear loose-fitting, long-sleeved shirts and pants" and "stay in air-conditioned places to keep insects outside." Among the registered active ingredients, picaridin is one that carries biting-fly coverage. The National Pesticide Information Center states that "picaridin can be used on human skin or clothing to repel mosquitoes, biting flies, ticks, fleas, and chiggers." It is "a human-made (synthetic) compound" made "to resemble the natural compound piperine, which is found in the group of plants that are used to produce black pepper," and it has been sold in the United States since 2005. ### How do I check a product before I buy it? Read the label, and read it for your pest. [EPA](https://www.epa.gov/insect-repellents/find-repellent-right-you) runs a search tool that lets you filter by "mosquitoes, ticks or both; protection time; active ingredient; or other product-specific information," and the agency's standing instruction is that "for the safe and effective use of pesticide products, always read the product label before using the product." If no-see-ums are your problem, the words to look for are flies, biting flies, or *Culicoides*. If they are not printed, assume the product was not tested on them. Because EPA's tool filters on mosquitoes and ticks rather than midges, we built something that answers this exact question. [The Repellent Index](https://longsleeve.com/repellent-index) holds all 631 EPA-registered skin repellents, and you can filter it by pest, including no-see-ums. Of those 631, 47 carry a no-see-um protection time we could read off their federal label. Every figure links back to the label it came from, ours included. **Longsleeve repels no-see-ums for up to 8 hours.** That is a registered claim, not a marketing line: the accepted federal label reads "Repels biting flies, stable flies, black flies, gnats, chiggers, sand flies and Scottish biting midges (no see-ums) for up to 8 hours." Scottish biting midges is the label's own name for the insect; no-see-ums is the parenthetical it gives alongside. Longsleeve is an EPA-registered picaridin lotion, EPA Reg. No. 101457-1. It repels mosquitoes and ticks for up to 14 hours, it is fragrance-free, and all nine of its ingredients are named on the tube. ### Common questions **Are no-see-ums the same as gnats?** "Gnat" is a loose word covering several small flies, most of which do not bite. No-see-ums are biting midges in the family Ceratopogonidae, and the females do bite. If something you could barely see drew blood, midge is the likelier answer. **Will a window screen keep no-see-ums out?** Usually not. The CDC states that "because of their small size, biting midges can crawl through most screens that otherwise keep out mosquitoes." Finer mesh exists and is sold for this purpose. **Do no-see-ums bite at a particular time of day?** It varies. Per the CDC, "biting midges can be out and around at different times of day, the time varies among different species." Treat the whole outdoor stretch as exposure rather than one window. **Does a mosquito repellent automatically work on no-see-ums?** Not automatically. The CDC directs people to repellents "labeled for flies, biting flies, or Culicoides." Coverage is established on the label, product by product, so check yours rather than assuming. **Why do no-see-ums bite me and not the person next to me?** Attraction varies between individuals and between midge species, and the published work on midges is thinner than it is for mosquitoes. The CDC itself notes that less is known about biting midges in the community than about mosquitoes. ### Related reading - [No-See-Um Repellent](https://longsleeve.com/blog/no-see-um-repellent). Check the label for biting midges. - [No-See-Um Bites](https://longsleeve.com/blog/no-see-um-bites). Why they itch, how long they last, and how to treat them. - [Gnat Repellent](https://longsleeve.com/blog/gnat-repellent). Biting midges, labels, screens, and fans. - [Sand Flea Bites](https://longsleeve.com/blog/sand-flea-bites). Midges, sand flies, true fleas, and treatment. More Longsleeve in your Google feed: ### Sources 1. CDC. Oropouche Puts Biting Midges Under the Microscope. [https://www.cdc.gov/oropouche/stories/midges-under-the-microscope.html](https://www.cdc.gov/oropouche/stories/midges-under-the-microscope.html) 1. CDC. Preventing Oropouche. [https://www.cdc.gov/oropouche/prevention/index.html](https://www.cdc.gov/oropouche/prevention/index.html) 1. Kampen H, Werner D. Biting Midges (Diptera: Ceratopogonidae) as Vectors of Viruses. Microorganisms, 2023;11(11):2706. [https://pmc.ncbi.nlm.nih.gov/articles/PMC10673010/](https://pmc.ncbi.nlm.nih.gov/articles/PMC10673010/) 1. National Pesticide Information Center. Picaridin Fact Sheet. [https://npic.orst.edu/factsheets/PicaridinGen.html](https://npic.orst.edu/factsheets/PicaridinGen.html) 1. US EPA. Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) Last reviewed 2026-08-24 · every claim on this page is sourced above Deeper on this insect: [what the bites look like and how to treat them](https://longsleeve.com/blog/no-see-um-bites), and [how to pick a repellent whose label lists them](https://longsleeve.com/blog/no-see-um-repellent). ## Permethrin Clothing: How Often to Re-Treat and How Long It Lasts URL: https://longsleeve.com/blog/permethrin-clothing > How often to re-treat permethrin clothing, how long self treated and factory treated fabric lasts, how long it dries, and why permethrin never goes on skin. Source: https://longsleeve.com/blog/permethrin-clothing By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 6, 2026 · Updated September 9, 2026 **Short answer:** How often you re-treat permethrin clothing depends on the label: one EPA-accepted 0.5 percent label says a treatment lasts two weeks, another says six weeks or the sixth laundering. One factory-treated apparel label, Insect Shield, EPA Reg. No. 74843-2, is printed for 70, 50 or 25 washings. Permethrin goes on clothing and gear, never on skin; the CDC says do not use permethrin products directly on skin. ### How often do you need to re-apply permethrin to clothes? Every two weeks on one EPA-accepted label, every six weeks or after the sixth laundering on another. The label on the bottle decides, and two 0.5 percent labels on file with the EPA give different numbers. The label for 0.5% Permethrin Aerosol Spray, EPA Reg. No. 71-1, says one clothing treatment lasts two weeks. It says the active ingredient binds to the fabric for residual protection lasting a minimum of two weeks, through several machine washings. Its limits are printed in capitals: do not retreat clothing more than once every two weeks, and launder clothing at least once before retreating. The label for CIC Residual Insecticide No. 1, EPA Reg. No. 50404-3, is written for six week protection, 42 days, against ticks, chiggers, mites and mosquitoes. It says protection lasts a minimum of six weeks through several machine washings, and that clothing should be retreated after six weeks or after the sixth laundering to maintain adequate protection. It also tells you not to exceed the recommended spraying times. Which schedule is yours comes down to the bottle you bought. The [CDC](https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html)'s rule covers both: read the product label to find out how long protection will last, then re-treat on that clock. ### How long do you let permethrin dry before wearing? At least two hours, or four hours under humid conditions. Both EPA-accepted 0.5 percent labels give that figure. The label for EPA Reg. No. 71-1 says to hang the treated clothing and allow it to dry for at least two hours, four under humid conditions, before wearing. The label for EPA Reg. No. 50404-3 puts the same numbers next to its spraying directions: treat the outer surfaces of each outfit, front and back, for 30 seconds on each side, then allow at least two hours to dry, or four hours in humid conditions. The 50404-3 label also carries an alternate set of directions that end with untying the garments and hanging them outdoors. Those directions say to hang the garments outdoors until dry, approximately two to three hours, and that when dry the garments are ready to wear. [NPIC](https://npic.orst.edu/pest/mosquito/ptc.html)'s instruction is about the fabric rather than the clock: hang treated fabrics outdoors and allow them to dry completely before wearing them. NPIC also says to apply the products outdoors, in well ventilated areas protected from wind. Treat the label's hours as the minimum and completely dry as the test. ### What is permethrin? The National Pesticide Information Center describes permethrin as an insecticide in the pyrethroid family, and pyrethroids as synthetic chemicals that act like natural extracts from the chrysanthemum flower. It was first registered with the U.S. Environmental Protection Agency in 1979 and re-registered in 2006, and NPIC counts more than 1,400 registered products containing it. The [EPA](https://www.epa.gov/insect-repellents/repellent-treated-clothing) is more technical: a broad spectrum, non-systemic, synthetic pyrethroid insecticide that targets adults and larvae of many species of biting, chewing, scaling, soil and flying invertebrates. And when used to pre-treat clothing, it is an insect repellent. ### Can you put permethrin on your skin? No. Three independent sources say so. The CDC says do not use permethrin products directly on skin, and its Yellow Book says permethrin should never be applied to the skin but only to clothing, mosquito nets or other fabrics as directed on the product label. NPIC says permethrin treatments are only intended for use on fabrics and should not be applied directly to the skin or other items. The EPA-accepted labels are the bluntest: the label for EPA Reg. No. 71-1 calls itself a clothing treatment only and says do not apply to skin, and the label for EPA Reg. No. 50404-3 says the product must not be applied to clothing while it is being worn, and that under no circumstances should bare skin or clothing on the body be treated. The reason is not mysterious. [NPIC](https://npic.orst.edu/factsheets/PermGen.pdf) notes that when people get permethrin on their skin they may have irritation or tingling, burning and itching at that spot, and in the eyes it can cause redness, pain or burning. Wearing the treated fabric is a different exposure. NPIC says permethrin applied properly binds tightly to fabrics, with little loss during washing and minimal transfer to skin, and the EPA says the amount allowed in clothing is very low, that human exposure from wearing factory-treated clothing is also low, and that available data show permethrin is poorly absorbed through the skin. The practical consequence: exposed skin needs its own product. The factory-treated apparel hang tag says, in capitals, to protect exposed skin with an insect repellent registered for direct application to skin, and the 0.5 percent clothing label says protection from mosquitoes can be further enhanced by applying a repellent to face, hands and other exposed areas of the body. Which one is its own question; we compare picaridin and DEET in [picaridin versus DEET](https://longsleeve.com/blog/picaridin-vs-deet). ### How does treated fabric actually stop a tick or a mosquito? By contact. [NPIC](https://npic.orst.edu/factsheets/repellents.html) is blunt about it: "Permethrin is not an insect repellent, but kills insects on contact. It is sometimes used to treat fabrics." An insect has to touch the treated item to be harmed or killed. What follows, per NPIC, is an attack on the insect nervous system, causing muscle spasms, paralysis and death. Permethrin is more toxic to insects than to people and dogs, because insects cannot break it down as quickly. The CDC frames it as both effects at once. Its Yellow Book calls permethrin a highly effective insecticide, an acaricide, meaning a pesticide lethal to ticks and mites, and a repellent, and says that at 0.5 percent, permethrin-treated clothing repels and kills the ticks, [chiggers](https://longsleeve.com/blog/chigger-bites) and mosquitoes that meet it, along with other biting and nuisance arthropods. Contact creates a hard boundary. The EPA states that when you wear permethrin factory-treated clothing, only the skin surface covered by that clothing is protected from the pests listed on the label, and that other exposed parts of the body should be treated with an insect repellent labeled for use on human skin. Treated pants do nothing for your forearms. The 0.5 percent label tells you to pay particular attention to socks, trouser cuffs and shirt cuffs, and to wear pant cuffs inside socks or footwear for full protection against [ticks](https://longsleeve.com/blog/tick-identification) and chiggers. ### Do permethrin treated socks and boots actually work? Yes, and footwear is the standout. NPIC says permethrin is not an insect repellent but kills insects on contact, so an insect has to touch the treated item, and applied properly it binds tightly to fabric. NPIC says permethrin is the only pesticide with an EPA registration for treating fabrics; the CDC says it can treat boots, clothing and camping gear. The hard number is from Miller and colleagues, Journal of Medical Entomology, March 2011, volume 48, issue 2. Researchers placed pathogen-free nymphal Ixodes scapularis on the left shoe, right leg and left arm of 15 volunteers in outfits untreated or treated with permethrin, commercially or with a do-at-home kit, and recorded attachment 2.5 hours later. Subjects in permethrin-treated sneakers and socks were 73.6 times less likely to have a tick bite than subjects in untreated footwear. Whole treated outfits took 3.36 times fewer bites; treated shorts and T-shirts made a bite 4.74 and 2.17 times less likely where they covered. Of attached nymphs, 97.6 percent were alive on untreated outfits, 22.6 percent on treated. Home and commercial treatment showed no statistically significant difference in the number of tick bites. The label for EPA Reg. No. 50404-3 agrees: pay particular attention to socks, trouser cuffs and shirt cuffs, and it says that in heavily infested areas protection from ticks is improved by wearing the cuffs inside footwear or taping pant cuffs around the legs. The factory-treated apparel label sets the limit: no insect protection product can guarantee complete protection from insects or insect bites, and the apparel does not protect against diseases or reactions from insect bites. ### How long does factory-treated clothing last? Longer than most people expect. The CDC says permethrin-treated items provide protection after multiple washings, and tells you to read the product label to find out how long. The Yellow Book is more specific: treated materials retain repellency or insecticidal activity after repeated launderings, and clothing treated before purchase is labeled for efficacy through many launderings. The numbers live on the label. The EPA-accepted hang-tag for Insect Shield Repellent Apparel (EPA Reg. No. 74843-2, permethrin 0.52 percent) carries the line "REPELLENCY REMAINS EFFECTIVE FOR [70][50][25] WASHINGS," with the bracketed figures marked on the label as optional or alternate text, so the number a given garment claims varies. The same label warns that dry cleaning removes the active ingredient. That tag is the pesticide label. The EPA treats factory-treated clothing as a pesticide product that must carry a pesticide use label, which on clothing is a hang-tag attached to the outside of the garment. Keep it. ### How long does clothing you treat yourself last? The label also tells you to keep doing the basics: avoid areas where pests are found, wear light-colored clothing with a long-sleeved shirt and long pants tucked into socks, and inspect your body daily for ticks. [How you pull one off](https://longsleeve.com/blog/tick-removal) matters too. ### How long does permethrin last on clothes, self treated versus factory treated? Two weeks to six weeks if you treat it yourself; the Insect Shield hang tag, EPA Reg. No. 74843-2, is printed for 70, 50 or 25 washings. The CDC says you can buy permethrin-treated clothing and gear or treat items yourself, and lists boots, shirts, pants, socks and tents among the items that can be treated. For factory-treated clothing, the EPA requires manufacturers to submit efficacy data for pests of public health concern such as mosquitoes and ticks, and says it reviewed those data and found the clothing effective in repelling target pests. | Treatment | EPA-accepted label | How long it lasts | Launderings | Re-treat rule | |---|---|---|---|---| | Self treated, aerosol spray | 0.5% Permethrin Aerosol Spray, EPA Reg. No. 71-1 | One clothing treatment lasts 2 weeks; residual protection for a minimum of two weeks | Holds up through several machine washings | Not more than once every two weeks; launder at least once before retreating | | Self treated, spray | CIC Residual Insecticide No. 1, EPA Reg. No. 50404-3, permethrin 0.50% | A minimum of six weeks, 42 days, against ticks, chiggers, mites and mosquitoes | Holds up through several machine washings | After six weeks or after the sixth laundering | | Factory treated apparel | Insect Shield Repellent Apparel hang tag, EPA Reg. No. 74843-2, permethrin 0.52% | Repellency remains effective for the number of washings printed on the tag | 70, 50 or 25 washings, carried on the label as alternate text; the garment's own tag shows which applies | Read the wash count on the hang tag; the CDC says the product label tells you how long protection lasts | Two rules make the table usable. First, the CDC says permethrin-treated items provide protection after multiple washings and tells you to read the product label to find out how long protection will last, so your own tag or bottle outranks this table. Second, wash treated clothing separately. The EPA says small amounts of permethrin can come off in the wash, that only outer clothing is treated because outer clothing is most likely to contact the listed pests, and that the label instructs consumers to wash permethrin-treated clothing separately from non-treated clothing. NPIC gives the same instruction. Fabric durability is counted in weeks and washings. The repellent on your exposed skin runs on a different clock, and we walk through it in [how long picaridin lasts](https://longsleeve.com/blog/how-long-does-picaridin-last). ### What do the CDC and EPA say about it? The CDC's tick prevention page lists it among the steps before going outdoors: treat clothing and gear with products containing 0.5 percent permethrin, which it says can be used on boots, clothing and camping gear and remains protective through several washings, or buy treated clothing and gear instead. Its mosquito prevention page is briefer, telling people to wear clothing and gear treated with permethrin, which it calls an insecticide that kills or repels mosquitoes. The EPA's position comes out of its registration process. It requires efficacy data for pests of public health concern such as mosquitoes and ticks, and says it reviewed those data for permethrin factory-treated clothing and found it effective in repelling target pests. Its 2009 revised assessment evaluated multiple exposure scenarios, including toddlers wearing or mouthing the clothing and military personnel wearing treated uniforms daily, and reported that all of them showed permethrin factory-treated clothing is unlikely to pose any significant immediate or long-term hazard to people wearing it. Permethrin was first registered for clothing use by the military in 1990, consumer factory-treated products followed in 2003, and it is still the only insect repellent used for factory treatment of clothing. ### What does EPA say about the safety of permethrin treated clothing? EPA states it plainly: "All exposure scenarios showed that permethrin factory-treated clothing is unlikely to pose any significant immediate or long-term hazard to people wearing the clothing." EPA reached that finding in a 2009 revised exposure and risk assessment covering multiple scenarios, including toddlers wearing or mouthing the clothing and military personnel who wear permethrin-treated uniforms daily. EPA says the April 2009 revision also evaluated short-term and long-term cancer risks to adults, youth and toddlers wearing the clothing, plus toddler object-to-mouth activity, and that "all scenarios resulted in risk estimates below our level of concern." EPA addresses mothers and children directly: "Based on our review of scientific studies, there is no evidence of reproductive or developmental effects to mother or child following exposure to permethrin." EPA adds that the amount of permethrin allowed in clothing is very low, that exposure from wearing it is also low, and that available data show permethrin is poorly absorbed through the skin. EPA also reviewed the efficacy data for permethrin factory-treated clothing and found it effective in repelling target pests. EPA also notes that small amounts of permethrin can come off in the wash, and that the label instructs consumers to wash treated clothing separately from non-treated clothing. Every line above is EPA describing permethrin factory-treated clothing, except the reproductive and developmental finding, which is EPA's statement about exposure to permethrin. ### How is this different from a repellent you put on your skin? Different job, different surface, different clock. Skin repellents go on [exposed skin or the outside of clothing](https://longsleeve.com/blog/bug-spray-on-clothes), never underneath. The [EPA](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients) lists the active ingredients in registered skin-applied insect repellents: DEET, picaridin, IR3535, oil of lemon eucalyptus, p-menthane-3,8-diol, 2-undecanone, catnip oil and oil of citronella. Those products go where fabric does not: face, hands and other exposed areas of the body. Durability is the sharpest contrast. The Yellow Book notes that clothing treated with other repellent products, such as DEET, protects against biting arthropods but will not last through washing and requires more frequent application. Permethrin bonds to the fabric and survives the laundry. Neither replaces the other. Wear the treated clothing, cover exposed skin separately: that is the layering behind [tick-bite prevention](https://longsleeve.com/blog/lyme-disease-prevention) and [mosquito-borne illness](https://longsleeve.com/blog/west-nile-virus) guidance alike. ### What does treated clothing not do? It does not make you invisible. The EPA-accepted label for factory-treated apparel carries two lines worth reading: that neither the apparel nor any other insect protection product can guarantee complete protection from insects or insect bites, and that it does not protect against diseases or reactions from insect bites. It does not work on everything, either. The Yellow Book states that permethrin-impregnated clothing and insect repellent have not been proven effective against tsetse flies. And it does not retire the routine. The CDC still wants a tick check after you come indoors, a shower within two hours, which it says has been shown to reduce the risk of getting Lyme disease, and clothes tumble dried on high heat for 10 minutes to kill ticks riding in on dry fabric. [Tick exposure can happen year-round](https://longsleeve.com/blog/tick-season-when), it notes, though ticks are most active April through September. ### How should you wash and handle treated clothing? Wash treated clothing separately. The EPA explains why: small amounts of permethrin can come off in the wash, only outer clothing is treated, and these products are not to be applied to certain clothing such as underwear. [Cats are the household exception](https://longsleeve.com/blog/is-permethrin-safe-around-pets). NPIC reports that cats are more sensitive to permethrin than dogs or people because it takes their bodies a long time to break it down, and that cats exposed by accident to products with high, 45 to 65 percent, levels of permethrin may seem anxious, may not walk normally, may have muscle tremors and seizures, and may die. NPIC also notes that permethrin is highly toxic to fish and other animals that live in water, and to bees and other beneficial insects, and it says to apply these products outdoors in well ventilated areas protected from wind. One more reason to handle [standing water around the house](https://longsleeve.com/blog/standing-water-mosquito-control) instead of spraying more. ### Common questions **Can I dilute permethrin and use it on my skin?** No. The CDC says not to use permethrin products directly on skin, and the Yellow Book says it should never be applied to the skin, only to clothing, mosquito nets or other fabrics as directed on the label. **Does permethrin wash out of treated clothing?** Some does. The EPA says small amounts of permethrin can come off in the wash, which is why the label tells you to wash treated clothing separately. Factory-treated garments carry a wash count on the hang-tag. One 0.5 percent label says self-treated clothing should be re-treated after six weeks or after the sixth laundering. Another EPA-accepted 0.5 percent label, Reg. No. 71-1, says one clothing treatment lasts two weeks, so the interval depends on the product you bought. **Is this the same permethrin used for head lice and scabies?** Same active ingredient, different regulatory category. NPIC notes that some permethrin products treat scabies and head lice on people, and that those are drugs regulated by the U.S. Food and Drug Administration. Clothing treatments are pesticides regulated by the EPA, with directions for fabric only. **Can you spray too much permethrin on clothes?** Yes, and the labels say not to. The label for EPA Reg. No. 50404-3 says do not exceed recommended spraying times, and not to treat underwear, hats, caps or inner clothing. NPIC says to read the application instructions carefully, apply according to the label directions, and not to over-treat. NPIC says any pesticide product with permethrin will not do: look for one with specific instructions for treating clothing. **Is permethrin toxic to humans?** NPIC says permethrin is more toxic to insects than to people and dogs because insects cannot break it down as quickly. On treated clothing, the EPA says permethrin is poorly absorbed through the skin, that all exposure scenarios showed factory-treated clothing is unlikely to pose any significant immediate or long-term hazard to wearers, and, about permethrin exposure generally, that it found no evidence of reproductive or developmental effects to mother or child. ### About Longsleeve Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients. None of this is medical advice. If you develop a rash or a fever after a bite, call your doctor and tell them what bit you. ### Related reading - [The Two-Layer System](https://longsleeve.com/blog/permethrin-picaridin-system). Why the CDC pairs treated clothing with skin repellent. - [Insect Repellent for Hiking and Backpacking](https://longsleeve.com/blog/insect-repellent-for-hiking). Gear, trailhead, trail, and the back-at-camp routine. - [DEET Safety: What the Evidence Actually Says](https://longsleeve.com/blog/deet-safety-evidence). EPA reviews, poison-center data, and the folklore, sorted. - [How to Remove a Tick](https://longsleeve.com/blog/tick-removal). The correct procedure, and the folk remedies that make things worse. - [Alpha-Gal Syndrome](https://longsleeve.com/blog/alpha-gal-syndrome). The delayed meat allergy that can follow a tick bite. - [Why Mosquitoes Bite Some People More](https://longsleeve.com/blog/why-mosquitoes-bite-some-people). What the research actually shows about attraction. - [Mosquito Bite Treatment](https://longsleeve.com/blog/mosquito-bite-treatment). What helps, what does not, and when to see a doctor. - [Our species field guide](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. CDC, About Permethrin-Treated Clothing and Gear. [https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html](https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html) 1. CDC, Preventing Tick Bites. [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. EPA, Repellent-Treated Clothing. [https://www.epa.gov/insect-repellents/repellent-treated-clothing](https://www.epa.gov/insect-repellents/repellent-treated-clothing) 1. EPA, Skin-Applied Repellent Ingredients. [https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients) 1. NPIC, Permethrin General Fact Sheet (PDF). [https://npic.orst.edu/factsheets/PermGen.pdf](https://npic.orst.edu/factsheets/PermGen.pdf) 1. NPIC, Insect Repellents Fact Sheet. [https://npic.orst.edu/factsheets/repellents.html](https://npic.orst.edu/factsheets/repellents.html) 1. NPIC, Permethrin Treated Clothing. [https://npic.orst.edu/pest/mosquito/ptc.html](https://npic.orst.edu/pest/mosquito/ptc.html) 1. EPA Pesticide Product Label, Insect Shield Repellent Apparel, EPA Reg. No. 74843-2 (PDF). [https://www3.epa.gov/pesticides/chem_search/ppls/074843-00002-20170515.pdf](https://www3.epa.gov/pesticides/chem_search/ppls/074843-00002-20170515.pdf) 1. EPA Pesticide Product Label, CIC Residual Insecticide No. 1, EPA Reg. No. 50404-3 (PDF). [https://www3.epa.gov/pesticides/chem_search/ppls/050404-00003-20151006.pdf](https://www3.epa.gov/pesticides/chem_search/ppls/050404-00003-20151006.pdf) 1. EPA Pesticide Product Label, 0.5% Permethrin Aerosol Spray, EPA Reg. No. 71-1 (PDF). [https://www3.epa.gov/pesticides/chem_search/ppls/000071-00001-20150716.pdf](https://www3.epa.gov/pesticides/chem_search/ppls/000071-00001-20150716.pdf) 1. PubMed, Miller NJ, Rainone EE, Dyer MC, Gonzalez ML, Mather TN. Tick bite protection with permethrin-treated summer-weight clothing. Journal of Medical Entomology, 2011, volume 48, issue 2, pages 327 to 333. [https://pubmed.ncbi.nlm.nih.gov/21485369/](https://pubmed.ncbi.nlm.nih.gov/21485369/) Last reviewed 2026-08-06 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Permethrin and Picaridin: The Two-Layer Tick and Mosquito System URL: https://longsleeve.com/blog/permethrin-picaridin-system > Permethrin goes on clothing, gear and bed nets; an EPA-registered repellent goes on skin. Which products contain permethrin and why it never touches skin. Source: https://longsleeve.com/blog/permethrin-picaridin-system By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 17, 2026 · Updated September 13, 2026 **Short answer:** The two-layer system is fabric plus skin. CDC guidance recommends 0.5 percent permethrin on clothing and gear, or pretreated clothing, and an EPA-registered insect repellent on exposed skin. EPA explains that treated clothing protects only the skin surface it covers, so exposed skin is a separate layer. Permethrin products should never be applied directly to skin. ### What are the two layers, and why do health agencies pair them? CDC tick guidance comes in two parts. First, treat clothing and gear with products containing 0.5 percent permethrin, which the CDC says can be used on boots, clothing, and camping gear and remains protective through several washings; buying pre-treated clothing and gear works too. Second, use an EPA-registered insect repellent on skin. Picaridin is among the named active ingredients, alongside DEET, IR3535, oil of lemon eucalyptus, para-menthane-diol, and 2-undecanone. The [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html)'s mosquito guidance stacks the same steps as separate line items: use an EPA-registered insect repellent, wear loose-fitting, long-sleeved shirts and pants, and wear clothing and gear treated with permethrin. Its tick messaging gets specific about what to treat: boots, pants, socks, and tents, or clothing pre-treated with permethrin. The EPA explains why the pairing matters. Permethrin-treated clothing protects only the skin surface the fabric covers, so the agency advises treating other exposed parts of the body with a repellent labeled for use on human skin for more complete protection. One layer lives on the fabric, one on the skin. If ticks are your main concern, our guide to [when tick season starts and peaks](https://longsleeve.com/blog/tick-season-when) covers the timing side. ### How does permethrin work, and how is a skin repellent different? The [CDC](https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html) describes permethrin as an insecticide that kills or repels mosquitoes. The CDC Yellow Book goes further, calling it a highly effective insecticide, acaricide (a pesticide that kills mites and ticks), and repellent. The EPA classifies it as a broad spectrum synthetic pyrethroid insecticide, and notes that when used to pre-treat clothing, it is an insect repellent. Permethrin sits in the pyrethroid family, synthetic chemicals that act like natural extracts from the chrysanthemum flower, per the National Pesticide Information Center ([NPIC](http://npic.orst.edu/factsheets/PermGen.html)). It can affect insects that touch it or eat it, acting on the insect nervous system and causing muscle spasms, paralysis, and death. NPIC notes it is more toxic to insects than to people and dogs because insects cannot break it down as quickly. At the 0.5 percent concentration used on clothing, the Yellow Book says treated fabric repels and kills chiggers, mosquitoes, ticks, and other biting and nuisance arthropods. The skin layer works on a different principle. Picaridin repels insects and makes them less likely to bite; [NPIC](http://npic.orst.edu/factsheets/PicaridinGen.html) says it seems to block mosquitoes from sensing their prey, and it does not kill them. It is a synthetic compound first made in the 1980s, designed to resemble piperine, a natural compound found in the group of plants used to produce black pepper. It can be used on human skin or clothing and repels mosquitoes, biting flies, ticks, fleas, and chiggers. That is the division of labor: an insecticide that also repels on your clothing, and a repellent that deters without killing on your skin. For a closer look at the skin-layer actives, see our [picaridin vs DEET comparison](https://longsleeve.com/blog/picaridin-vs-deet). ### Why does permethrin never go on skin? Three sources, one rule. The CDC's mosquito prevention page instructs: do not use permethrin products directly on skin. The [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) Yellow Book states that permethrin should never be applied to the skin, only to clothing, mosquito nets, or other fabrics as directed on the product label. NPIC says the same thing from the pesticide side: permethrin treatments are intended only for fabrics, should not be applied directly to skin, and only products with specific instructions for treating clothing should be used. ### Should you buy factory-treated gear or treat your own? Permethrin is the only insect repellent currently used for factory treatment of clothing, per the [EPA](https://www.epa.gov/insect-repellents/repellent-treated-clothing). The agency first registered permethrin in 1979, registered it for use on clothing for the military in 1990, and registered the first consumer-oriented factory-treated clothing products in 2003. NPIC notes the U.S. military has used permethrin to treat combat uniforms for over 20 years to protect soldiers from diseases carried by insects. Per the CDC Yellow Book, factory-treated clothing is labeled for efficacy through many launderings, and the EPA's 2009 revised risk assessment, which evaluated scenarios including toddlers mouthing treated clothing and military personnel wearing treated uniforms daily, found factory-treated clothing unlikely to pose any significant immediate or long-term hazard to the people wearing it. The DIY route runs through spray-on products the EPA registers for consumers to treat their own clothing against mosquitoes and ticks; the products currently available contain DEET, permethrin, or picaridin. For permethrin sprays, [NPIC](http://npic.orst.edu/pest/mosquito/ptc.html)'s instructions are specific: do not apply permethrin to clothing while it is being worn, apply outdoors in well ventilated areas protected from wind, and hang treated fabrics to dry completely before wearing them. The CDC Yellow Book adds that self-treated items must be treated 24 to 48 hours before packing so they can dry, and that label instructions should always be followed. The Yellow Book also notes travelers can treat clothing, hats, shoes, mosquito nets, outerwear, and camping gear with permethrin, and CDC travel packing lists include clothing and gear such as boots, socks, and tents treated with 0.5 percent permethrin. Durability is where permethrin earns the clothing job. The CDC says permethrin-treated clothing provides protection after multiple washings. The Yellow Book notes treated materials retain repellency or insecticidal activity through repeated launderings and should be retreated as described on the product label. When applied properly, NPIC says, permethrin binds tightly to fabric, with little loss during washing and minimal transfer to the skin; it is the only pesticide the EPA approves for these clothing uses. Clothing treated with skin repellent products such as DEET behaves differently: the Yellow Book says that treatment will not last through washing and requires more frequent application. The EPA passes along the label's wash-day fine print: small amounts of permethrin can come off in the wash, only outer clothing gets treated (never items like underwear), and treated clothing gets washed separately from non-treated clothing. Our [permethrin clothing guide](https://longsleeve.com/blog/permethrin-clothing) walks through the whole process. ### What about permethrin-treated bed nets? A treated net is the layer for sleeping, and the CDC says a permethrin-treated mosquito net provides more protection than an untreated one. The CDC's trigger: sleep under a mosquito net if sleeping outside or when screened rooms are not available. [WHO](https://www.who.int/news-room/fact-sheets/detail/malaria)'s malaria fact sheet says to use mosquito nets when sleeping in places where malaria is present. How it works, in their words. The [CDC](https://www.cdc.gov/mosquitoes/prevention/about-mosquito-nets.html) says permethrin, an insecticide, kills or repels mosquitoes and other insects. Its malaria program page says bed nets form a protective barrier around people sleeping under them, that insecticide-treated nets are much more protective than untreated ones, and that the insecticides kill and repel mosquitoes. WHO's instruction booklet for treated nets says the insecticide on the net kills or keeps away mosquitoes. For a traveler it is the third fabric layer, so the skin rule still governs it: the CDC Yellow Book puts mosquito nets on the list of items travelers can treat with permethrin, and never the skin. The CDC's buying advice: a compact, white, rectangular net with 156 holes per square inch, long enough to tuck under the mattress. Tuck it, check for holes or tears, and do not sleep directly against the net, since mosquitoes can still bite through holes in it. The CDC's wider avoidance list and the pre-trip clinician conversation are in our guide to [malaria prevention for travelers](https://longsleeve.com/blog/malaria-prevention-travelers). ### Which products contain permethrin? More than 1,400 registered products contain permethrin, per NPIC, and only the clothing and gear products belong in this two-layer system. The categories below are the EPA's, the CDC's and NPIC's. - Clothing and gear sprays: the consumer spray-on products the EPA registers for clothing, covered above. - Factory-treated apparel and gear: the CDC says you can buy permethrin-treated clothing and gear or treat items yourself, and lists boots, shirts, pants, socks, and tents. - Bed nets, covered above: NPIC lists clothing, shoes, bed nets, and camping gear as treatable. - Pet and livestock products: flea products for dogs on the EPA's list; cattle ear tags, flea collars and spot-on treatments for dogs per NPIC. The cat and dog questions are in our guide to [permethrin around pets](https://longsleeve.com/blog/is-permethrin-safe-around-pets). - Home, farm and public health uses: residential indoor and outdoor insect foggers and sprays, termite treatments, agricultural and livestock products, and mosquito abatement products on the EPA's list; food and feed crops, ornamental lawns, and structures and buildings on NPIC's. The EPA calls permethrin the most widely used mosquito adulticide in the United States. - Lice and scabies treatments: regulated by the Food and Drug Administration as drugs, per both the EPA and NPIC. The sorting rule is NPIC's: any pesticide product with permethrin will not do, so look for products with specific instructions for treating clothing. The how-to lives in our [permethrin clothing guide](https://longsleeve.com/blog/permethrin-clothing). ### What about cats? [Cat owners run into permethrin warnings](https://longsleeve.com/blog/is-permethrin-safe-around-pets) and deserve the full picture, including the concentrations involved. NPIC states that cats are more sensitive to permethrin than dogs or people because it takes their bodies a long time to break it down. Its fact sheet describes what accidental exposure to high concentration products can do: cats exposed to products with 45 to 65 percent permethrin may seem anxious, may be unable to walk normally, may have muscle tremors and seizures, and may die from the exposure. Read those numbers carefully. The caution describes products in the 45 to 65 percent range. The clothing treatments in CDC guidance contain 0.5 percent permethrin, and the EPA notes the amount of permethrin allowed in clothing is very low. That does not erase the sensitivity NPIC describes, so the Yellow Book's standing advice applies: as with all pesticides, follow the label instructions. ### Which repellents belong on the skin layer? The CDC calls an EPA-registered insect repellent the best way to prevent mosquito bites. Its active ingredient list for skin: DEET, picaridin (known as KBR 3023 and icaridin outside the United States), IR3535, oil of lemon eucalyptus, para-menthane-diol, and 2-undecanone. On the EPA's roster of skin-applied repellent ingredients, picaridin appears in about 40 registered products. The registration itself carries information. An EPA registration number on the label means the company provided EPA with technical information on the effectiveness of the product. Application rules from the Yellow Book: apply repellents only to exposed skin or clothing, as directed on the product label, and not to skin covered by clothing. In general, higher concentrations of active ingredients provide longer protection, regardless of the active ingredient. Building a kit for the trail? Our [hiking repellent guide](https://longsleeve.com/blog/insect-repellent-for-hiking) puts both layers together. On the skin layer, a note about ours: Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients. ### Frequently asked questions **Can permethrin go on skin if I run out of repellent?** No. The CDC instructs: do not use permethrin products directly on skin. The CDC Yellow Book says it should never be applied to the skin, only to clothing, mosquito nets, or other fabrics as directed on the product label. **How many washes does a permethrin treatment survive?** The CDC says treated clothing remains protective through several washings, and factory-treated clothing is labeled for efficacy through many launderings. The Yellow Book advises retreating as described on the product label for continued protection. **Can children use the skin-layer repellents?** Per the CDC Yellow Book, insect repellents containing DEET, picaridin, IR3535, and 2-undecanone can be used on children without age restriction. Use them as directed on the product label, and talk to your pediatrician if you have questions about a specific child. **Sunscreen and repellent: which goes on first?** The CDC Yellow Book advises using separate products, applying sunscreen first , and then applying the repellent. **If my clothes are treated, do I still need repellent on skin?** Yes, for exposed skin. The EPA notes that treated clothing protects only the skin surface it covers, and advises treating exposed parts of the body with a repellent labeled for use on human skin for more complete protection. **Can you use permethrin and DEET together?** Yes, as two layers in two places: the CDC's mosquito guidance lists them as separate steps, use proven EPA-registered insect repellents, a list that includes DEET and picaridin in the skin-layer section above, and wear clothing and gear treated with permethrin. The CDC Yellow Book's rule for the skin step is to apply repellents only to exposed skin or clothing, as directed on the product label, and not to skin covered by clothing. Which active takes the skin job is the subject of our picaridin versus DEET comparison . **Does permethrin repel or kill?** Both. The CDC's shorthand is that permethrin is an insecticide that kills or repels mosquitoes; the mechanism, and how it differs from a repellent that only deters, is in the section above on how permethrin works. ### Related reading - [Permethrin-Treated Clothing](https://longsleeve.com/blog/permethrin-clothing). How often to re-treat, how long it lasts, and why it never goes on skin. - [Insect Repellent for Hiking](https://longsleeve.com/blog/insect-repellent-for-hiking). Ticks, mosquitoes, permethrin, and skin repellent. - [Lyme Disease Prevention](https://longsleeve.com/blog/lyme-disease-prevention). Tick checks, repellent, permethrin, and removal. - [How Long Does Picaridin Last?](https://longsleeve.com/blog/how-long-does-picaridin-last) Skin, clothes, and shelf life. More Longsleeve in your Google feed: ### Sources 1. CDC, Preventing Tick Bites: [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. CDC, Preventing Mosquito Bites: [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC, Tick Bite Prevention Press Kit: [https://www.cdc.gov/ticks/communication-resources/press-kit.html](https://www.cdc.gov/ticks/communication-resources/press-kit.html) 1. CDC, Preventing Mosquito Bites While Traveling: [https://www.cdc.gov/mosquitoes/prevention/preventing-mosquito-bites-while-traveling.html](https://www.cdc.gov/mosquitoes/prevention/preventing-mosquito-bites-while-traveling.html) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods: [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. EPA, Repellent-Treated Clothing: [https://www.epa.gov/insect-repellents/repellent-treated-clothing](https://www.epa.gov/insect-repellents/repellent-treated-clothing) 1. EPA, Skin-Applied Repellent Ingredients: [https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients) 1. National Pesticide Information Center, Permethrin General Fact Sheet: [http://npic.orst.edu/factsheets/PermGen.html](http://npic.orst.edu/factsheets/PermGen.html) 1. National Pesticide Information Center, Permethrin Treated Clothing: [http://npic.orst.edu/pest/mosquito/ptc.html](http://npic.orst.edu/pest/mosquito/ptc.html) 1. National Pesticide Information Center, Picaridin General Fact Sheet: [http://npic.orst.edu/factsheets/PicaridinGen.html](http://npic.orst.edu/factsheets/PicaridinGen.html) 1. CDC, About Mosquito Nets, updated March 5, 2025. [https://www.cdc.gov/mosquitoes/prevention/about-mosquito-nets.html](https://www.cdc.gov/mosquitoes/prevention/about-mosquito-nets.html) 1. CDC, Insecticide-Treated Nets (Malaria, For Public Health), updated April 2, 2024. [https://www.cdc.gov/malaria/php/public-health-strategy/insecticide-treated-nets.html](https://www.cdc.gov/malaria/php/public-health-strategy/insecticide-treated-nets.html) 1. WHO, Malaria fact sheet, 4 December 2025. [https://www.who.int/news-room/fact-sheets/detail/malaria](https://www.who.int/news-room/fact-sheets/detail/malaria) 1. WHO, Instructions for treatment and use of insecticide-treated mosquito nets, 2002 (WHO/CDS/RBM/2002.41). [https://iris.who.int/handle/10665/67573](https://iris.who.int/handle/10665/67573) 1. EPA, Permethrin, Resmethrin, d-Phenothrin (Sumithrin): Synthetic Pyrethroids For Mosquito Control. [https://www.epa.gov/mosquitocontrol/permethrin-resmethrin-d-phenothrin-sumithrinr-synthetic-pyrethroids-mosquito-control](https://www.epa.gov/mosquitocontrol/permethrin-resmethrin-d-phenothrin-sumithrinr-synthetic-pyrethroids-mosquito-control) 1. CDC, About Permethrin-Treated Clothing and Gear, updated May 14, 2024. [https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html](https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html) Last reviewed 2026-08-17 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Picaridin Lotion vs Spray: Which Repellent Form Works Better? URL: https://longsleeve.com/blog/picaridin-lotion-vs-spray > A 12-hour trial found 20% picaridin spray and lotion equal at the same dose. What decides protection, and what our read of EPA's data shows at 14 hours. Source: https://longsleeve.com/blog/picaridin-lotion-vs-spray By [Andrew Rothaus](https://longsleeve.com/about), Founder · September 9, 2026 **Short answer:** Neither, at the same concentration and dose. In a 12-hour trial against lone star tick nymphs, 20% picaridin spray and 20% picaridin lotion showed no difference in effectiveness, and the authors called them of equivalent efficacy. Concentration and the amount on your skin do most of the work; in that trial the container did not change the result. ### Is picaridin lotion or spray better? Neither, once the concentration and the dose are held equal. The one direct test we have is a 2010 trial by Carroll and colleagues in the Journal of Medical Entomology, run over 12 hours against nymphs of the lone star tick. On picaridin it found one thing: there was no difference in effectiveness between the 20% spray and 20% lotion formulations. The gap was not statistically significant, and the authors concluded that the spray and lotion formulations of picaridin were of equivalent efficacy. How the repellents went on matters. Carroll's team applied lotion and cream with a nitrile-gloved hand and spray with a pipette, to ensure a measured and even application over the surface being treated. No one misted from a can at arm's length, so in the picaridin arm the concentration and the dose were the same on both sides. The same paper shows why most lotion-versus-spray comparisons prove nothing. Its IR3535 arm used a spray and a lotion at different concentrations, and the authors wrote that because of this, no conclusions can be drawn about which type of application was more effective. One trial against one tick species is not a literature, and it says nothing about mosquitoes. What it does show is that when concentration and dose were held equal, the container stopped mattering. ### What actually decides how long you are protected? Concentration, the amount you put on, and how much of it survives your day. The [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html)'s Yellow Book puts concentration first: in general, higher concentrations of active ingredients provide longer duration of protection, regardless of the active ingredient. A 2018 paper by Goodyer and Schofield in the Journal of Travel Medicine calls applied dosage one important variable in determining the persistence of a repellent experienced by users. Coverage is where people go wrong in both directions. The CDC tells travelers to use just enough repellent to cover exposed skin or clothing, says heavy application and saturation are generally unnecessary for effectiveness, and adds that if biting insects do not respond to a thin film, apply a bit more. The American Academy of Pediatrics says the same about children: using more does not make the repellent more effective. Under-applying fails the other way. [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively)'s guidance is to apply the amount indicated by the label, since if you do not follow the label directions, the product may not be as effective as you expect. Then the day gets a vote. The CDC says product efficacy and duration of protection are markedly affected by ambient temperature, level of activity, amount of perspiration, exposure to water, being rubbed off during activities, and other factors. Sweat does not check which container the repellent came from. ### Where do the hours on a repellent label come from? From a test of that exact product on human skin, run to an EPA guideline. EPA's product performance guideline for skin-applied repellents says repellent efficacy should be tested using the end-use formulation as registered or as proposed for registration. The objective of most of that testing, in EPA's words, is to estimate how long after treatment a repellent will continue to protect users from the target pest, measured as Complete Protection Time. [EPA](https://www.epa.gov/insect-repellents/find-repellent-right-you) also says there are variations in the resulting protection times because of differences in the testing conditions. EPA now allows manufacturers to apply to add a graphic on skin-applied repellent labels communicating the repellency time for mosquitoes and ticks. The part nobody expects: EPA measures the dose differently for a lotion and a spray. The guideline says recommended methods for choosing the standard dose depend in part on the active ingredients and formulations of the test material. For a lotion, the applied quantity can be determined by weighing the container before and after use. For a spray, a different method is needed, because less than all the spray released from a pump-spray or aerosol container will reach the target limb, and in that method skin is left exposed between bracelets to help subjects determine when they achieve complete coverage. Either way, the guideline says subjects in repellency trials should all be treated at the same standard dose rate, with consistent application and uniform coverage. Measured and even application is what the Carroll trial's gloved hand and pipette were for. We keep the label hours from EPA's skin-applied repellent database in the [Repellent Index](https://longsleeve.com/repellent-index). ### Do lotions really show longer hours on EPA labels? At the 14-hour mark, yes, and that is our own reading of EPA's data rather than anything EPA has said. In our read of EPA's database of skin-applied repellents, 4 of 631 products reach a 14-hour mosquito protection figure, and all four are 20% picaridin lotions. The median mosquito protection time among the 337 products that state one is 8 hours. Both counts are on the Index's [statistics page](https://longsleeve.com/repellent-index/statistics), tallied from EPA's data as mirrored on August 18, 2026, so check there first. For scale, the [American Academy of Pediatrics](https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx) says 20% picaridin can provide protection for 8 to 12 hours, and 5% for 3 to 4 hours. Concentration is doing the work in that sentence. Now the caveat that keeps this honest. Four lotions at the 14-hour mark is a market observation, not proof that the lotion form causes longer protection. Formulation is not always neutral, either. The CDC says sustained-release or controlled-release (microencapsulated) formulations, even with lower active ingredient concentrations, might provide longer protection times. What the data does not say is that any lotion beats any spray. ### How long does picaridin lotion last? The American Academy of Pediatrics says products with 20% picaridin can provide protection for 8 to 12 hours, and 5% picaridin for 3 to 4 hours. What shortens the real number is the CDC's list: temperature, activity, perspiration, water, and being rubbed off. Our post on [how long picaridin lasts](https://longsleeve.com/blog/how-long-does-picaridin-last) goes through the duration evidence in depth. ### Why do sprays come with instructions that lotions do not? Because some of a spray never reaches your skin, and none of it has to travel through the air first with a lotion. EPA's repellent guidance has lines that apply to one form only. When using sprays, do not spray directly into the face; spray on hands first and then apply to face. Do not spray in enclosed areas. Avoid breathing a spray product. All three are written for sprays. There is no lotion version of any of them. The National Pesticide Information Center explains why: picaridin may be inhaled when sprays are used around the body, especially in indoor spaces where the vapors may remain for some time. The American Academy of Pediatrics gives parents the same two rules, use spray repellents in open areas to avoid breathing them in, and avoid sprays in pressurized containers if children might accidentally inhale them or get them into their eyes. Read this as an asymmetry rather than a warning. The trial in the first section found spray and lotion equal once the dose was controlled. ### Which form should you hand a kid? A stick, a lotion or an unpressurized spray, in the American Academy of Pediatrics' words. The AAP tells parents to choose products in the form of sticks, lotions or unpressurized sprays, listed together, with no ranking. What it steers away from is sprays in pressurized containers if children might accidentally inhale them or get them into their eyes, and it says to use spray repellents in open areas to avoid breathing them in. Two more AAP rules apply whichever form you pick. Use just enough repellent to cover your child's clothing and exposed skin, since using more does not make it more effective. And do not put insect repellent directly on your child's face: the AAP's instruction is to spray a little on your hands first and then rub it on, avoiding the eyes and mouth. Ages and more are in our post on [mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). ### How does picaridin compare with DEET on skin? The question assumes a ranking the evidence does not hand out, so here are the picaridin facts on their own. The National Pesticide Information Center's fact sheet says picaridin has been widely used as an insect repellent in Europe and Australia, but has only been available in the United States since 2005. In humans, less than 6% of the picaridin applied to skin was absorbed, and rats and humans excrete almost all of it in their urine within a day of exposure. [NPIC](https://npic.orst.edu/factsheets/archive/Picaridintech.html)'s technical fact sheet also reports that researchers noted no dermal irritation on the backs of human subjects following the application of 20% picaridin aerosol, 20% picaridin lotion, or technical grade picaridin. The study covered the 20% aerosol and the 20% lotion alike. For the comparison itself, read our [picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet) post, and for the evidence on DEET, [the DEET safety evidence](https://longsleeve.com/blog/deet-safety-evidence). ### How should you apply either form? Thin, even and complete, at the amount the label says. EPA's instruction is to read and follow the label directions, be sure you understand how much to apply, and apply the amount indicated by the label, because if you do not follow the label directions the product may not be as effective as you expect. The CDC's version: just enough to cover exposed skin, and a bit more if biting insects do not respond to a thin film. For the face, both forms go on through your palms. EPA's rule for sprays is do not spray directly into the face; [spray on hands first and then apply to face](https://longsleeve.com/blog/bug-spray-on-face). Our own label says the same for the lotion, apply on face by first spreading small amounts in palms of hands and spreading on face and neck, avoiding your eyes, and adds: apply evenly to skin in a thin layer, do not exceed two applications per day, and excessive amounts or more frequent reapplication should be unnecessary. Cover every patch of exposed skin, because the Carroll trial and EPA's test method both hinge on measured, even and complete coverage. ### Common questions **Does lotion repellent work as well as spray?** At the same concentration and dose, yes. In a 12-hour trial against lone star tick nymphs, there was no difference in effectiveness between the 20% spray and 20% lotion formulations of picaridin, and the authors called them of equivalent efficacy. A 2007 field study in Parasitology Research tested three hydro-alcoholic spray solutions and four skin lotions; all gave a time to first bite between 5 h 20 min and 6 h 50 min, a mean of roughly 6 hours. **How long does picaridin lotion last?** The American Academy of Pediatrics says products with 20% picaridin can provide protection for 8 to 12 hours, and 5% picaridin for 3 to 4 hours. In our read of EPA's database, 4 of 631 skin-applied products reach a 14-hour mosquito figure, and all four are 20% picaridin lotions. The CDC says temperature, activity, perspiration, water and rub-off markedly affect the real duration. **What body lotion repels insects?** An EPA-registered repellent lotion, and the number to read is the concentration. The CDC says higher concentrations of active ingredients provide longer duration of protection, regardless of the active ingredient. In our read of EPA's database of skin-applied repellents, the four products that reach a 14-hour mosquito figure are all 20% picaridin lotions. Look for the active ingredient and its percentage on the label. **Can I use picaridin lotion on my face?** Yes, through your hands. EPA's rule for sprays is do not spray directly into the face; spray on hands first and then apply to face. The American Academy of Pediatrics says the same for a child's face: hands first, then rub it on, avoiding the eyes and mouth. Our label reads: apply on face by first spreading small amounts in palms of hands and spreading on face and neck, avoiding your eyes. **Is picaridin lotion okay for kids?** The American Academy of Pediatrics tells parents to choose products in the form of sticks, lotions or unpressurized sprays, so lotion is on its list. The AAP says products with 20% picaridin can provide protection for 8 to 12 hours and 5% picaridin for 3 to 4 hours, and to use just enough to cover clothing and exposed skin, because using more does not make it more effective. Ages are in our post on mosquito repellent for kids . ### About Longsleeve Longsleeve is an EPA-registered [picaridin lotion](https://longsleeve.com/product) (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with [nine disclosed ingredients](https://longsleeve.com/ingredients). Its label directions: apply evenly to skin in a thin layer, no more than two applications a day. ### Related reading - [How long does picaridin last?](https://longsleeve.com/blog/how-long-does-picaridin-last). The duration evidence in depth. - [Picaridin vs DEET](https://longsleeve.com/blog/picaridin-vs-deet). The comparison, side by side. - [DEET safety evidence](https://longsleeve.com/blog/deet-safety-evidence). What the studies on DEET actually found. - [Mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). Ages and application for children. - [The Repellent Index](https://longsleeve.com/repellent-index). Label hours from EPA's skin-applied repellent database. - [Does Bug Spray Expire? What EPA's Label Rules Actually Require](https://longsleeve.com/blog/does-bug-spray-expire). What EPA's label rules actually require, plus heat, freezing and disposal. - [Bug Spray and Sunscreen: Which Goes On First, How Long to Wait, and Why Not a Combo](https://longsleeve.com/blog/bug-spray-and-sunscreen). Sunscreen first, then repellent, and why not a combo. - [Bug Spray on Clothes or Skin? What Goes Where, What DEET Does to Synthetics, and How to Wash It Out](https://longsleeve.com/blog/bug-spray-on-clothes). What DEET does to synthetics, and how to wash it out. - [Should You Wash Off Bug Spray? What the Label Says About Bedtime, Hikes, and Kids](https://longsleeve.com/blog/wash-off-bug-spray). Before bed, after the hike, and on kids. ### Sources 1. Carroll JF, Benante JP, Kramer M, Lohmeyer KH, Lawrence K. Journal of Medical Entomology 2010;47(4):699-704. [https://pmc.ncbi.nlm.nih.gov/articles/PMC7027251/](https://pmc.ncbi.nlm.nih.gov/articles/PMC7027251/) 1. CDC Yellow Book 2026, Mosquitoes, Ticks, and Other Arthropods. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. Goodyer L, Schofield S. Journal of Travel Medicine 2018;25(suppl_1):S10-S15. [https://pubmed.ncbi.nlm.nih.gov/29718433/](https://pubmed.ncbi.nlm.nih.gov/29718433/) 1. American Academy of Pediatrics, HealthyChildren.org, Insect Repellents. [https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx](https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx) 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. EPA, Product Performance Test Guidelines OPPTS 810.3700: Insect Repellents to be Applied to Human Skin (EPA 712-C-10-001, July 7, 2010). [https://downloads.regulations.gov/EPA-HQ-OPPT-2009-0150-0011/content.pdf](https://downloads.regulations.gov/EPA-HQ-OPPT-2009-0150-0011/content.pdf) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. NPIC, Picaridin General Fact Sheet. [https://npic.orst.edu/factsheets/PicaridinGen.html](https://npic.orst.edu/factsheets/PicaridinGen.html) 1. NPIC, Picaridin Technical Fact Sheet. [https://npic.orst.edu/factsheets/archive/Picaridintech.html](https://npic.orst.edu/factsheets/archive/Picaridintech.html) 1. Naucke TJ, Kropke R, Benner G, et al. Parasitology Research 2007;101(1):169-177. [https://pubmed.ncbi.nlm.nih.gov/17252270/](https://pubmed.ncbi.nlm.nih.gov/17252270/) Last reviewed 2026-09-09 · every claim on this page is sourced above ## Picaridin vs DEET: Duration, Kids, Ticks, and Materials URL: https://longsleeve.com/blog/picaridin-vs-deet > Picaridin vs DEET from EPA, CDC, AAP, NPIC, and field studies: how they work, how long they last, child guidance, tick use, odor, and material compatibility. Source: https://longsleeve.com/blog/picaridin-vs-deet By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 16, 2026 · Updated October 1, 2026 **Short answer:** The CDC lists both picaridin and DEET among the active ingredients in the EPA-registered repellents it tells people to use. On duration, the CDC says that in general, higher concentrations of active ingredients provide longer duration of protection, regardless of the active ingredient, and that duration varies considerably among products. On gear, NPIC says DEET can damage certain plastics and synthetic fabrics; the sources gathered here do not say how picaridin interacts with materials. Choose by the label, the pest, and what you are wearing. ### What are picaridin and DEET? Picaridin is a human-made (synthetic) compound first made in the 1980s that repels insects, ticks, and [chiggers](https://longsleeve.com/blog/chigger-bites), per the National Pesticide Information Center (NPIC). It was developed by Bayer using molecular modeling and was made to resemble piperine, a natural compound found in the group of plants used to produce black pepper. It has been widely used in Europe and Australia, was first registered by the EPA in 2001, and has been available in the United States since 2005. DEET (N,N-diethyl-meta-toluamide) is the active ingredient in many repellent products and is widely used against mosquitoes and ticks, per the [EPA](https://www.epa.gov/insect-repellents/deet). It was developed by the U.S. Army in 1946 and registered for use by the general public in 1957. The EPA estimates that one-third of the U.S. population uses DEET every year. [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html)'s Yellow Book notes that the EPA characterizes both DEET and picaridin as "conventional" repellents, while OLE, PMD, IR3535, and 2-undecanone are biopesticide repellents derived from, or synthetic versions of, natural materials. ### How do picaridin and DEET compare at a glance? Every cell comes from a primary source; where sources are silent, the cell says so. | Attribute | Picaridin | DEET | |---|---|---| | First made | First made in the 1980s, by Bayer, using molecular modeling (NPIC) | Developed by the U.S. Army in 1946 (EPA) | | U.S. registration | First registered by EPA in 2001; available in the United States since 2005 (NPIC) | Registered for use by the general public in 1957 (EPA) | | Also known as | Icaridin (WHO), KBR 3023, Bayrepel (NPIC) | N,N-diethyl-meta-toluamide (EPA) | | How it works | Seems to block mosquitoes from sensing their prey; does not kill insects (NPIC) | Makes it hard for biting insects to smell people; repels rather than kills (EPA). Scientists do not know exactly how DEET works on all insects (NPIC) | | Odor | "Nearly odorless" (EPA fact sheet); NPIC describes technical-grade picaridin as a colorless liquid with little odor | A liquid with "a distinct, faint odor" (NPIC) | | Duration, as stated per source | AAP: 5% protects for 3 to 4 hours; 20% protects for 8 to 12 hours | EPA database: ticks for about two to ten hours, mosquitoes for two to twelve hours, depending on percentage. AAP: 10% for about 2 hours, 30% for about 5 hours; concentrations above 50% do not provide longer protection | | Children | CDC Yellow Book: can be used on children without age restriction | CDC Yellow Book: can be used on children without age restriction. EPA: approved for use on children with no age restriction. AAP: not on children younger than 2 months, no more than once per day on older children, lowest concentration available | | Materials | Not addressed by our sources | A plasticizer; can damage certain rubber, plastic, vinyl, or elastic materials; does not damage natural fibers, including cotton and wool (NPIC) | | In the body | Absorbed picaridin is almost all excreted in urine within a day (NPIC) | Broken down by the liver; nearly all eliminated, mainly in urine, within 24 hours (NPIC) | | Registered products | About 40 (EPA ingredient list) | More than 500 (EPA ingredient list); about 120 from about 30 companies (EPA DEET page) | ### Which one should you choose? Either one, as far as the CDC is concerned: the CDC lists both DEET and picaridin among the active ingredients in the EPA-registered repellents it tells people to use. The useful question is what you need the repellent to do. Here is what the sources say, sorted by the thing you care about most. **Hours of protection.** The [American Academy of Pediatrics](https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx) gives hours for each by concentration: products with 5% picaridin can protect for 3 to 4 hours and 20% picaridin for 8 to 12 hours; 10% DEET provides protection for about 2 hours and 30% DEET for about 5 hours, and a higher DEET concentration works for a longer time, though anything over 50% does not provide longer protection. These are separate AAP statements, not results from one test of the two side by side, and the agency sources gathered for this article give no picaridin hours to check the AAP figures against. EPA says studies in its database indicate DEET repels mosquitoes from two to twelve hours and ticks for about two to ten hours, depending on the percentage of DEET in the product. The CDC says that in general, higher concentrations provide longer protection regardless of the active ingredient, and that duration varies considerably among products, so the number that counts is the one on the label you are holding. **Plastics, gear and synthetic fabrics.** [NPIC](https://npic.orst.edu/factsheets/archive/DEETtech.html) describes DEET as a plasticizer that can damage certain rubber, plastic, vinyl, or elastic materials, and certain synthetic or treated fabrics. It says DEET does not damage natural fibers including cotton and wool. The sources gathered for this article do not address how picaridin interacts with materials, so this row makes no claim about picaridin either way. **Smell.** [NPIC](https://npic.orst.edu/factsheets/archive/Picaridintech.html) describes technical grade picaridin as a colorless liquid with little odor, and DEET as a liquid with a distinct, faint odor. Both describe the chemical itself, not a finished product. **Children.** The CDC says repellents containing DEET or picaridin can be used on children without age restriction, and EPA's DEET page says that active is approved for use on children with no age restriction. [NPIC](https://npic.orst.edu/factsheets/DEETgen.html) reports that the American Academy of Pediatrics has recommended that DEET not be used on children younger than 2 months of age; the sources gathered for this article give no AAP age guidance for picaridin either way. NPIC says there are currently no data to suggest that children have increased sensitivity specifically to picaridin, and the EU regulation approving icaridin requires product assessments to pay particular attention to children younger than two years. Follow the product label, and ask your pediatrician about your own child. The form of the product matters as well as the active. [Picaridin lotion vs spray](https://longsleeve.com/blog/picaridin-lotion-vs-spray) covers that, and [how long picaridin lasts](https://longsleeve.com/blog/how-long-does-picaridin-last) covers duration by concentration. ### How does each repellent work? Neither ingredient kills insects. Per [NPIC](https://npic.orst.edu/factsheets/PicaridinGen.html), picaridin "seems to block mosquitoes from sensing their prey." The EPA says DEET "works by making it hard for these biting bugs to smell us," and NPIC reports that insects exposed to DEET cannot locate a person or animal because they cannot detect them, though scientists do not know exactly how DEET works on all insects. NPIC states picaridin can be used on skin or clothing against mosquitoes, biting flies, ticks, fleas, and chiggers, in pump sprays, liquids, aerosols, and wipes. The EPA states DEET products for skin come as liquids, lotions, sprays, and impregnated materials, in concentrations from 5 to 99 percent. An [EPA](https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/fs_PC-080301_1-Apr-98.pdf) fact sheet lists DEET for use against pests including biting flies, biting midges, black flies, chiggers, deer flies, fleas, gnats, horse flies, mosquitoes, [no-see-ums](https://longsleeve.com/blog/no-see-um-bites), sand flies, stable flies, and ticks. ### How long does each repellent last? Duration depends on concentration, and the numbers vary by source. The American Academy of Pediatrics states that 10% DEET provides protection for about 2 hours, that 30% DEET protects for about 5 hours, and that concentrations above 50% do not provide longer protection. For picaridin, the AAP states that 5% products can protect against mosquitoes and ticks for 3 to 4 hours, and 20% products for 8 to 12 hours. Concentration is not the only variable: protection time is approved product by product through EPA registration, using each formulation's own submitted efficacy data, which is why two products at the same percentage can carry different label times. We walk through how those numbers are set in [how long picaridin lasts](https://longsleeve.com/blog/how-long-does-picaridin-last). Studies in EPA's database indicate DEET repels ticks for about two to ten hours and mosquitoes for two to twelve hours, depending on the percentage of DEET. The EPA cautions that registered products' protection times vary because of differences in testing conditions. It also lists conditions that change any repellent's effectiveness: physical activity and perspiration, water exposure, air temperature, and how attractive an individual is to mosquitoes and ticks. We break the picaridin numbers down further in [how long does picaridin last](https://longsleeve.com/blog/how-long-does-picaridin-last). ### What do head-to-head field studies show? Two field studies in our sources tested the ingredients side by side. A two-year field study in Cambodia (PLoS Neglected Tropical Diseases, 2014) found that picaridin 20% "performed equally well as DEET 20%." Across the repellents tested, the overall five-hour protection rate was 97.4%. The same study found that repellent performance varied by mosquito genus and species for the repellents tested. An earlier field study in Australia (Journal of Medical Entomology, 2004) found that both picaridin and DEET formulations protected well against Culex annulirostris and relatively poorly against Anopheles species. For travel, the World Health Organization's malaria prevention guidance lists using mosquito repellents containing DEET, IR3535, or icaridin after dusk. ### Is 20% picaridin as effective as 30% DEET? No study gathered for this article tested exactly 20% picaridin against 30% DEET on mosquitoes. The one study here that tested those exact strengths was on ticks, and it favored DEET; it is described below. The mosquito evidence compares the two at equal or near-equal strength. A 2018 review in the Journal of Travel Medicine by Goodyer and Schofield examined published tests comparing the two and found that, overall, the studies showed little potential difference between DEET and picaridin applied at the same dosage, with some evidence pointing to a superior persistence for picaridin. The authors note that only eight field studies and three laboratory studies met their criteria, and that most were considered to be of high risk of bias and of lower quality. Their conclusion: where only 30% DEET or lower concentrations are available, it is reasonable to offer DEET or picaridin as a first choice, and where products above 50% DEET are available, the protection time advantage of those formulations can be invoked to consider them first. Two studies in this set give the detail. In a two-year field study in Cambodia, Van Roey and colleagues reported that picaridin 20% performed equally well as DEET 20% and better than picaridin 10%. In a trial by Frances and colleagues, 19.2% picaridin provided more than 95% protection against Culex annulirostris for 5 hours, and both DEET formulations tested, 20% DEET in ethanol and 35% DEET in a gel, did so for 7 hours, when collections ceased. On ticks, Gliniewicz and colleagues, testing Dermacentor reticulatus, reported that at 90 minutes a 30% DEET repellent was 100% effective while a 20% icaridin repellent had dropped to 95%, and that the icaridin repellent was effective only up to four hours after application. They concluded that DEET was the most effective repellent against that tick species. The CDC cautions that repellent efficacy and duration vary considerably among products and among arthropod species, which applies to every study in this section. ### What do health agencies say about safety? The [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html) recommends using an EPA-registered insect repellent. On the health record, the EPA concluded that insect repellents containing DEET "do not present a health concern," and an EPA fact sheet states the agency believes normal use of picaridin "does not present a health concern to the general U.S. population." Both are the agencies' own words. We walk through the DEET record in [the DEET safety evidence](https://longsleeve.com/blog/deet-safety-evidence). On what happens after application: NPIC reports that in humans, less than 6% of picaridin applied to skin was absorbed, and almost all of it is excreted in urine within a day of exposure. NPIC reports the liver breaks down absorbed DEET, with nearly all of it eliminated, mainly in urine, within 24 hours of application. For specific health situations, talk with your clinician. ### Is picaridin allowed in Europe? Yes. In Europe it goes by icaridin, and the European Union approved it by regulation. Commission Implementing Regulation (EU) 2020/1086 of 23 July 2020 says: "Icaridin is approved as an active substance for use in biocidal products of product-type 19," the category the regulation describes as repellents and attractants. The regulation's annex lists the approval as running from 1 February 2022 to 31 January 2032. It followed an opinion of the European Chemicals Agency adopted on 10 December 2019 by the Biocidal Products Committee and, in view of the risks identified for the uses assessed, it requires that product assessments pay particular attention to children younger than two years following dermal and secondary exposure. DEET holds an EU approval for the same product type: a 2024 Commission decision records its inclusion as an active substance for product-type 19 and postponed the expiry date of that approval. NPIC says picaridin has been widely used as an insect repellent in Europe and Australia, but has only been available in the United States since 2005. The World Health Organization's malaria fact sheet names icaridin alongside DEET and IR3535 as mosquito repellents to use after dusk. ### Can you use picaridin every day, and does it have side effects? How often you can apply it is set by the product label. EPA's picaridin fact sheet says the agency requires use directions on picaridin labels that include when to reapply and restrictions on how often to apply. The CDC's advice for any repellent is to reapply if you start getting bitten, but not more often than the label allows. On side effects, NPIC says some people have had skin irritation from using products containing picaridin, although this is very uncommon, and that picaridin may cause irritation if it gets into someone's eyes. [EPA](https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-070705_01-May-05.pdf)'s fact sheet says the agency believes that the normal use of picaridin does not present a health concern to the general U.S. population. On long-term use, NPIC reports no human data. In animal studies NPIC describes, researchers applied large amounts of picaridin to the skin of rats and rabbits for up to two years: the parent animals' skin got thicker, became irritated, and developed dark spots, there were no effects on the offspring, and rats given the highest doses had heavier livers. No source here speaks to years of daily use in people. The agencies' practical guidance covers each application instead: the CDC says to use just enough repellent to cover exposed skin or clothing, and EPA says to wash treated skin with soap and water after returning indoors. If a rash or other reaction appears, the CDC says to wash the product off with mild soap and water and discontinue its use. For questions about your own skin or a daily routine, ask your doctor. ### What is the guidance for children? The American Academy of Pediatrics and the CDC both recommend using an EPA-registered insect repellent product. Beyond that, framing differs by source; here is each as stated. - The AAP has recommended that DEET not be used on children younger than 2 months, that it be applied no more than once per day on older children, and that products with the lowest DEET concentration available be used (as reported by NPIC). - The EPA states it has approved DEET for use on children with no age restriction and no restriction on concentration. - CDC's Yellow Book states that insect repellents containing DEET, picaridin, IR3535, and 2-undecanone "can be used on children without age restriction." - The CDC says not to use products containing OLE or PMD on children under 3 years old. CDC's application rules for children apply to repellents generally: never apply to a child's hands, eyes, mouth, cuts, or irritated skin, and adults should apply repellent to their own hands first, then to the child's face. More on this in [mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). For your own child, talk with your pediatrician. ### Which materials does each one affect? Per NPIC's technical fact sheet, DEET acts as [a plasticizer and can damage certain rubber, plastic, vinyl, or elastic materials](https://longsleeve.com/blog/bug-spray-on-clothes) such as contact lenses, eyeglass frames and lenses, watch crystals, combs, painted and varnished surfaces, and certain synthetic or treated fabrics. The same source states DEET does not damage natural fibers, including cotton and wool. Our sources do not address how picaridin interacts with materials, so this article makes no claim either way. ### Frequently asked questions **Is picaridin the same thing as icaridin?** Yes. The World Health Organization refers to the chemical as icaridin, and other names include KBR 3023 and Bayrepel, per NPIC. The CDC notes picaridin is known as KBR 3023 and icaridin outside the United States. **Can I use sunscreen with either repellent?** The CDC says to apply sunscreen first and insect repellent second . CDC's Yellow Book states that repellents applied according to label instructions can be used with sunscreen with no reduction in repellent activity, but that limited data show DEET-containing repellents applied over sunscreen decrease the sunscreen's SPF by one-third. The AAP's don't-use list for children includes combination sunscreen and repellent products, because sunscreen must be reapplied often. **Do both work on ticks?** For ticks, the CDC recommends EPA-registered repellents containing DEET, picaridin, IR3535, OLE, PMD, or 2-undecanone. NPIC states that picaridin repels insects, ticks, and chiggers, and an EPA fact sheet lists ticks among the pests DEET products are used against. **Why does the EPA registration number matter for both?** Per the CDC, an EPA registration number on the label means the company provided EPA with technical information on the product's effectiveness. The EPA states that registration of skin-applied repellents indicates evaluation and approval for human safety and effectiveness when used according to the label, including review for vulnerable populations. By contrast, minimum-risk ingredients exempt from registration have not been evaluated for effectiveness, and the CDC says the effectiveness of non-EPA-registered repellents, including some natural repellents, is not known. Disclosure: Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. ### Related reading - [Picaridin Lotion vs Spray](https://longsleeve.com/blog/picaridin-lotion-vs-spray). How the two forms compare. - [How Long Does Picaridin Last?](https://longsleeve.com/blog/how-long-does-picaridin-last) Skin, clothes, and shelf life. - [DEET Safety](https://longsleeve.com/blog/deet-safety-evidence). EPA Reviews, CDC Guidance, Kids, and Common Questions. - [Natural Bug Repellents](https://longsleeve.com/blog/natural-repellents). EPA Registration, Plant Oils, OLE, PMD, and Evidence. More Longsleeve in your Google feed: ### Sources 1. NPIC, Picaridin General Fact Sheet: [https://npic.orst.edu/factsheets/PicaridinGen.html](https://npic.orst.edu/factsheets/PicaridinGen.html) 1. NPIC, Picaridin Technical Fact Sheet: [https://npic.orst.edu/factsheets/archive/Picaridintech.html](https://npic.orst.edu/factsheets/archive/Picaridintech.html) 1. EPA, Picaridin Pesticide Fact Sheet (May 2005): [https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-070705_01-May-05.pdf](https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-070705_01-May-05.pdf) 1. EPA, DEET: [https://www.epa.gov/insect-repellents/deet](https://www.epa.gov/insect-repellents/deet) 1. NPIC, DEET General Fact Sheet: [https://npic.orst.edu/factsheets/DEETgen.html](https://npic.orst.edu/factsheets/DEETgen.html) 1. NPIC, DEET Technical Fact Sheet: [https://npic.orst.edu/factsheets/archive/DEETtech.html](https://npic.orst.edu/factsheets/archive/DEETtech.html) 1. EPA, DEET Reregistration Fact Sheet (April 1998): [https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/fs_PC-080301_1-Apr-98.pdf](https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/fs_PC-080301_1-Apr-98.pdf) 1. CDC, Preventing Mosquito Bites: [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC, Preventing Tick Bites: [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. EPA, Regulation of Skin-Applied Repellents: [https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents](https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents) 1. EPA, Skin-Applied Repellent Ingredients: [https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients](https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients) 1. American Academy of Pediatrics, HealthyChildren.org, Insect Repellents: [https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx](https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx) 1. EPA, Find the Repellent that is Right for You: [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. EPA, Using Insect Repellents Safely and Effectively: [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. PLoS Neglected Tropical Diseases, 2014, field study in Cambodia: [https://pubmed.ncbi.nlm.nih.gov/25522134/](https://pubmed.ncbi.nlm.nih.gov/25522134/) 1. Journal of Medical Entomology, 2004, field study in Australia: [https://pubmed.ncbi.nlm.nih.gov/15185943/](https://pubmed.ncbi.nlm.nih.gov/15185943/) 1. CDC Yellow Book, Mosquitoes, Ticks and Other Arthropods: [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. World Health Organization, Malaria Fact Sheet: [https://www.who.int/news-room/fact-sheets/detail/malaria](https://www.who.int/news-room/fact-sheets/detail/malaria) 1. Longsleeve, Facts: [https://longsleeve.com/facts](https://longsleeve.com/facts) 1. Goodyer and Schofield, J Travel Med 2018;25(suppl_1):S10-S15 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/29718433/](https://pubmed.ncbi.nlm.nih.gov/29718433/) 1. Gliniewicz et al., Przegl Epidemiol 2019;73(1):117-125 (PubMed abstract). [https://pubmed.ncbi.nlm.nih.gov/31134780/](https://pubmed.ncbi.nlm.nih.gov/31134780/) 1. Commission Implementing Regulation (EU) 2020/1086 of 23 July 2020, OJ L 239, 24.7.2020. [https://eur-lex.europa.eu/eli/reg_impl/2020/1086/oj](https://eur-lex.europa.eu/eli/reg_impl/2020/1086/oj) 1. Commission Implementing Decision (EU) 2024/2950 of 29 November 2024, OJ L, 3.12.2024. [https://eur-lex.europa.eu/eli/dec_impl/2024/2950/oj](https://eur-lex.europa.eu/eli/dec_impl/2024/2950/oj) Last reviewed 2026-08-16 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Sand Flea Bites: Midges, Sand Flies, True Fleas, and Treatment URL: https://longsleeve.com/blog/sand-flea-bites > What people call sand flea bites at the beach are often biting midges or sand flies. How to tell them apart, when tropical tungiasis matters, and how CDC bite care helps. Source: https://longsleeve.com/blog/sand-flea-bites By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 26, 2026 The "sand fleas" that bite American beachgoers are usually not fleas at all. They are biting midges (no-see-ums) or sand flies, and each has its own playbook. The true sand flea, the chigoe flea Tunga penetrans, is a tropical parasite of sandy climates, not a U.S. beach-blanket problem. Few bite names cause more confusion than "sand flea." The term gets applied to at least three different creatures, only one of which is a flea, and the right response depends entirely on which one you actually met. Here is how to tell, using what the CDC and state health guidance actually say. ### What are "sand fleas," really? On a U.S. beach, the itchy welts blamed on sand fleas usually come from **biting midges**, the insects the CDC describes as "tiny biting midges, sometimes called 'no-see-ums.'" The Illinois Department of Public Health puts them among the most serious pests "along the shores of oceans, lakes, ponds and rivers," biting day or night, and so small they pass through window screens. If you never saw what bit you and the welts arrived in clusters, this is the leading suspect; our [no-see-um guide](https://longsleeve.com/blog/no-see-ums) covers them in full. **Short answer:** The bites many U.S. beachgoers call sand flea bites usually come from biting midges or sand flies, not true fleas. Clustered itchy welts after a beach or lakeside evening point toward no-see-ums or sand flies. A nodular swelling after barefoot exposure in tropical sandy places is different and belongs with a clinician, because CDC describes true chigoe flea tungiasis as a burrowing-flea problem. The third, the **true sand flea**, is the one the name legally belongs to: the chigoe flea, *Tunga penetrans*, per the CDC. It is a genuinely different problem: the CDC's parasitology reference explains that mated females burrow into the skin of the host, causing a nodular swelling. Its territory, per the [CDC](https://www.cdc.gov/dpdx/tungiasis/index.html), is tropical and subtropical regions, including Mexico to South America, the West Indies and Africa, in sandy climates including beaches, stables and farms. If you have not traveled to those regions, tungiasis is almost certainly not your diagnosis; if you have, and a bite has become a swelling nodule, that is a clinician conversation, not a blog-post fix. ### Do sand flies carry disease? In parts of the world, yes. Illinois DPH notes that certain sand fly species (Lutzomyia), in many parts of the world including southern Texas in the United States, are suspected of transmitting cutaneous leishmaniasis, a protozoan disease. The [CDC](https://www.cdc.gov/leishmaniasis/prevention/index.html)'s prevention guidance is built on one fact: "There are no vaccines or drugs to prevent leishmaniasis infection," so protecting yourself against sand fly bites is the prevention. For travelers to affected regions, that elevates bite prevention from comfort to health protection. ### How do you prevent the bites? The CDC's sand fly prevention guidance, in three moves: - **Repellent, applied thoroughly.** Use an EPA-registered insect repellent on exposed skin and under the ends of sleeves and pant legs. The CDC's leishmaniasis guidance notes that repellents containing DEET are generally the most effective for this use. - **Indoors, screened or air-conditioned.** The CDC advises staying in well-screened or air-conditioned areas when indoors in sand fly country. - **For the beach no-see-um problem,** the same tactics that work on biting midges apply, since they are usually the actual biter: a repellent whose label lists biting flies or no-see-ums, and moving air. Our [no-see-um repellent guide](https://longsleeve.com/blog/no-see-um-repellent) has the full label-reading walkthrough. Worth restating as a traveler's rule: within the United States, the beach-biter question is almost always midges versus sand flies, an itch-management problem. The tropical burrowing flea enters the picture with travel to the regions the CDC names, and its signature, per the CDC's reference, is not a welt but a nodular swelling as the burrowed female develops. Different organism, different response, different urgency. ### How do you treat the bites you already have? For the ordinary itchy welts, the [CDC](https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html)'s bite-care steps: wash the bite and surrounding area with soap and water, and apply an ice pack for 10 minutes to reduce swelling and itching, reapplying as needed. And the standing rule: "Do not scratch bites. They can become infected." The exception is the true sand flea scenario: a nodular swelling after barefoot time in tropical sandy places. That is tungiasis territory, and it belongs in front of a clinician. Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours, and its accepted federal label carries the claim "Repels biting flies, stable flies, black flies, gnats, chiggers, sand flies and Scottish biting midges (no see-ums) for up to 8 hours." It is fragrance-free, with nine disclosed ingredients. Of the 631 EPA-registered skin repellents in [our Repellent Index](https://longsleeve.com/repellent-index), 47 carry a stated no-see-um protection time on their federal label. ### Short answers **What do sand flea bites look like?** The clustered itchy welts American beachgoers call sand flea bites usually come from biting midges or sand flies, and they behave like other insect bites: bumps that itch and respond to the CDC's wash-ice-don't-scratch routine. A bite that becomes a swelling nodule after tropical travel is different: that pattern belongs to the true sand flea, Tunga penetrans, and warrants a clinician. **Are sand fleas and no-see-ums the same thing?** In everyday American usage, usually yes: the biters on the beach at dusk are typically biting midges, the insects called no-see-ums. The technical name "sand flea" belongs to a tropical burrowing flea that is a different organism entirely. **How do I tell midge bites from sand fly bites?** Timing is the most usable clue. Illinois DPH notes most sand fly species feed at night, while biting midges bite during the day or at night and mass along shorelines. In practice the response is the same: a repellent whose label covers biting flies, screens fine enough to matter, and the CDC's bite care for what already itches. **When do sand flies bite?** At night, mostly. Illinois DPH notes most sand fly species feed on blood at night, which distinguishes them from the day-and-night biting midges. **Should I worry about leishmaniasis at a U.S. beach?** The suspected U.S. transmission Illinois DPH names is in southern Texas, and the CDC's prevention guidance is aimed at people living in or visiting countries where leishmaniasis occurs. For travelers to those regions, sand fly bite prevention is the whole defense: there is no vaccine or preventive drug. The usual suspect in full: [no-see-ums](https://longsleeve.com/blog/no-see-ums), [their bites](https://longsleeve.com/blog/no-see-um-bites), and [the repellents that list them](https://longsleeve.com/blog/no-see-um-repellent). ### Related reading - [No-See-Um Bites](https://longsleeve.com/blog/no-see-um-bites). Why they itch, how long they last, and how to treat them. - [Chigger Bites](https://longsleeve.com/blog/chigger-bites). How long they itch and why they look like they spread. - [Mosquito Bite Treatment](https://longsleeve.com/blog/mosquito-bite-treatment). Itch relief, swelling, infection signs, and when to seek care. - [No-See-Ums](https://longsleeve.com/blog/no-see-ums). What they are and what repels them. - [The species almanac](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. Illinois Department of Public Health, Biting Flies. [https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html](https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-control/biting-flies.html) 1. CDC, Oropouche Puts Biting Midges Under the Microscope. [https://www.cdc.gov/oropouche/stories/midges-under-the-microscope.html](https://www.cdc.gov/oropouche/stories/midges-under-the-microscope.html) 1. CDC, Preventing Leishmaniasis. [https://www.cdc.gov/leishmaniasis/prevention/index.html](https://www.cdc.gov/leishmaniasis/prevention/index.html) 1. CDC DPDx, Tungiasis. [https://www.cdc.gov/dpdx/tungiasis/index.html](https://www.cdc.gov/dpdx/tungiasis/index.html) 1. CDC, About Mosquito Bites. [https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html](https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html) Last reviewed 2026-08-26 · every claim on this page is sourced above ## CDC Standing Water Rule: Empty and Scrub Containers Once a Week URL: https://longsleeve.com/blog/standing-water-mosquito-control > Standing water mosquito control: the CDC says empty and scrub weekly, EPA says empty and change weekly, and the CDC names Bti for water you cannot dump. Source: https://longsleeve.com/blog/standing-water-mosquito-control By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 6, 2026 · Updated September 13, 2026 Standing water is where mosquitoes are made. [EPA](https://www.epa.gov/mosquitocontrol/success-mosquito-control-integrated-approach) calls egg and larva interventions generally the most effective, least costly way to control mosquitoes. The CDC's instruction is to empty and scrub, turn over, cover, or throw out anything holding water once a week, because an egg can reach adulthood in 7 days. CDC and EPA home guidance is built almost entirely around containers. Water sitting in something on your property, or the one next door, is where the next generation gets built. Containers are the one stage of the life cycle a homeowner can reach. ### Why does standing water decide how many mosquitoes you get? EPA lays out the life cycle in four stages: egg, larva, pupa, adult. The agency's summary is the whole argument in one line: "The first three stages occur in water, but the adult is an active flying insect." Three of those four stages happen in water you can tip over. **Short answer:** Standing water is where mosquitoes are made. CDC guidance is to empty and scrub, turn over, cover, or throw out items that hold water once a week. That weekly cadence matters because the CDC says mosquito eggs can develop into adults in 7 to 10 days, and *Aedes* eggs can stick to container walls and survive drying out for months. Then it moves fast. The [CDC](https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html) gives the same figure for both groups: a mosquito egg takes 7 to 10 days to develop into an adult. EPA's cross-species estimate is that "The life cycle typically takes up two weeks, but depending on conditions, it can range from 4 days to as long as a month." ### How little water does a mosquito actually need? Less than you think. The CDC states it plainly: "Mosquitoes only need a small amount of water to lay eggs. Bowls, cups, fountains, tires, barrels, vases, and any other container storing water make a great 'nursery.'" EPA goes smaller still, listing [Aedes aegypti](https://longsleeve.com/blog/aedes-aegypti) sites as "old tires, buckets, toys, potted plant trays and saucers, plastic covers and even places as small as bottle caps," with a preference for "dark-colored containers located in the shade." Dry does not mean clear, either. CDC says *Aedes* eggs "can survive drying out for up to 8 months" and "can even survive a winter in the southern United States." Floodwater species lay above the water line, and per the [CDC](https://www.cdc.gov/mosquitoes/about/where-mosquitoes-live_1.html) "The eggs dry out, then hatch when rain floods the soil or container." An empty saucer that has sat dry for a month is still well inside that 8 month window. ### Which containers does the CDC actually name? The [CDC](https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-at-home.html)'s home control page names these directly: "tires, buckets, planters, toys, pools, birdbaths, flowerpot saucers, or trash containers." Its larvicide guidance adds "Buckets and rain barrels," "Fountains," "Gutters or downspouts," "Non-chlorinated swimming pools," "Pool covers that collect water," "Tires," and tree holes. Two categories are easy to miss. The CDC tells homeowners to "Fill tree holes" and to "Repair cracks or gaps in your septic tank if you have one. Cover open vent or plumbing pipes." It does not stop at the door: "Mosquitoes entering your house from outdoors can start laying eggs indoors," so the weekly routine applies to indoor items "such as vases or flowerpot saucers." For water you do not own, in "Neglected swimming pools," "Trash," "Discarded tires," or "Drainage ditches with standing water," the [CDC](https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-in-a-community.html) says to call your local mosquito control board or health department. ### Why once a week, and why scrub? The weekly interval sits at the fast end of the 7 to 10 day egg-to-adult window the CDC gives for both *Aedes* and *Culex*. That is why the CDC's instruction is weekly and not monthly. The scrubbing is the part people skip, and it is the part that deals with eggs glued above the waterline. The CDC's instruction is to "empty and scrub, turn over, cover, or throw out any items that hold water," and the reason it gives is "to remove mosquito eggs and larvae." Tipping a birdbath removes the water. Scrubbing the sides removes the eggs. For water you want to keep, the CDC says to "Tightly cover water storage containers (buckets, cisterns, rain barrels) so mosquitoes cannot get inside to lay eggs," and "For containers without lids, use wire mesh with holes smaller than an adult mosquito." EPA adds: "Keep swimming pool water treated and circulating." ### What does the EPA say about standing water? Empty and change the water in the containers that hold it, at least once a week, and get rid of standing water everywhere else. That is [EPA](https://www.epa.gov/insect-repellents/tips-prevent-mosquito-bites)'s own instruction, on its Tips to Prevent Mosquito Bites page: "Empty and change the water in bird baths, fountains, wading pools, rain barrels, and potted plant trays at least once a week to destroy potential mosquito habitats." The rest of EPA's list overlaps the CDC's above: "Eliminate standing water in rain gutters, old tires, buckets, plastic covers, toys, or any other container where mosquitoes can breed," and "Drain or fill temporary pools of water with dirt." Old tires, buckets, plastic covers and toys are also on EPA's [Aedes aegypti](https://longsleeve.com/blog/aedes-aegypti) list higher up this page. EPA's reason is eggs: "An important part of mosquito control around homes is making sure that mosquitoes don't have a place to lay their eggs." Its Bti page puts the same instruction at the smallest scale, "Eliminate any standing water (even tiny amounts)," to keep mosquitoes from laying eggs there. Between the two agencies the calendar is the same, weekly, on anything that holds water; the scrub step is the CDC's wording. How many weeks that runs depends on your region, laid out in [when mosquito season starts and ends](https://longsleeve.com/blog/mosquito-season-by-region); if the water sits where you eat, see [keeping mosquitoes away from a patio dinner](https://longsleeve.com/blog/how-to-keep-mosquitoes-away-from-patio-dinner). ### What do you do with water you cannot dump? That is what larvicides are for. The CDC's rule is narrow: use larvicides on standing water that "Will not be used for drinking" and "Cannot be covered, dumped, or removed," which its Bti fact sheet illustrates with "rain barrels, fountains, ornamental ponds, septic tanks, and pools that are not in use." The [CDC](https://www.cdc.gov/mosquitoes/mosquito-control/larvicides.html) says "Homeowners can use mosquito dunks or bits that contain larvicide," applied by hand to small bodies of water. The larvicide the CDC lists first is Bti, *Bacillus thuringiensis* subspecies *israelensis*, a soil bacterium the CDC calls "toxic to mosquito larvae, blackflies, and fungus gnats" that "has been used for mosquito control for more than 30 years." One limit matters: the CDC states flatly that "Bti does not control biting female mosquitoes." It works on the nursery only. EPA has registered five strains of Bti across 48 pesticide products. Its toxins "specifically affect the larvae of only mosquitoes, black flies and fungus gnats" and "do not affect other types of insects including honey bees." The National Pesticide Information Center adds that Bt "has to be eaten to work." On use, the CDC is direct: "Follow the instructions on the label. Do not apply more than directed or reapply more often than instructed." ### What container control cannot do EPA is honest about the ceiling: "Egg and larva interventions are generally the most effective, least costly, way to control mosquitoes. However, these interventions are unlikely to be 100% effective, especially for mosquitoes like the *Aedes aegypti* that breed in varied and scattered locations." In those cases, EPA says, "eliminating or treating all or even most standing water can be nearly impossible." So the [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html) pairs water control with barriers and personal protection: "Use screens on windows and doors," "Use air conditioning, if available," and "Wear loose-fitting, long-sleeved shirts and pants." For repellents, the CDC says to "Use EPA-registered insect repellents" with one of six active ingredients it lists: DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, and 2-undecanone. The CDC names active ingredients, not brands, and tells everyone to "Always follow the product label instructions." ### What does the evidence say about the devices people buy instead? Start with the regulatory gap. Bug zappers, insect traps, and ultrasonic sound generators are classified by EPA as devices, not pesticides. Per [EPA](https://www.epa.gov/pesticides/pesticide-devices-guide-consumers)'s consumer guide, "FIFRA does not require devices to undergo premarket review and registration," and manufacturers "do not submit their claims or efficacy and safety data to EPA (for approval or otherwise) before selling or distributing a device." On the number on the box, the agency is blunt: "An EPA establishment number on device packaging does NOT indicate that the product has been reviewed for safety or efficacy by EPA." Then the field data. A 2007 Cochrane systematic review of electronic mosquito repellents, the ultrasonic units, found ten qualifying field studies. "All 10 studies found that there was no difference in the number of mosquitoes caught from the bare body parts of the human participants with or without an EMR." The authors' conclusion: "Field entomological studies confirm that EMRs have no effect on preventing mosquito bites." Electric zappers have their own record. Frick and Tallamy, in Entomological News in 1996, counted every insect killed in six suburban traps over a season. Out of 13,789 insects there were "only 31 biting flies, a minute proportion (0.22%)," while the traps destroyed "1,868 predators and parasites (13.5%) and 6,670 nonbiting aquatic insects (48.4%)." Their verdict: "electric insect traps are worthless for biting fly reduction." Wearables did not fare much better in a 2017 wind tunnel study in the Journal of Insect Science. Of five wearable devices tested against *Aedes aegypti*, "only the one that releases Metofluthrin significantly reduced the numbers of attracted mosquitoes. The [citronella candle](https://longsleeve.com/blog/citronella-and-plant-repellents) had no effect." ### Does your neighbor's bucket matter? Enormously, and so does yours. The CDC notes that *Aedes aegypti* and *Ae. albopictus* "don't fly long distances" and that "In their lifetime, these mosquitoes will only fly a few blocks." *Culex* mosquitoes "don't fly long distances but have been known to fly up to 2 miles (3.2 km)." Either way the range is short, which is why EPA says "Residents, neighbors, and landlords can all be proactive in eliminating standing water or alerting others to its presence." If numbers in your area are high, the CDC says to call your local or state health department or mosquito control program. If ticks are also on your list, we cover their calendar in [when tick season runs](https://longsleeve.com/blog/tick-season-when). ### Where Longsleeve fits Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients, all listed on our [facts page](https://longsleeve.com/facts). ### Common questions **How much standing water does it take to breed mosquitoes?** Very little. The CDC says mosquitoes "only need a small amount of water to lay eggs," naming bowls, cups, tires, barrels, and vases. EPA's list of Aedes aegypti sites includes "even places as small as bottle caps." **Why once a week instead of once a month?** The CDC puts egg-to-adult development at 7 to 10 days for both Aedes and Culex mosquitoes, which is why its instruction is weekly rather than monthly. **Is dumping the water enough, or do I need to scrub?** The CDC's wording is "empty and scrub," and the stated purpose is "to remove mosquito eggs and larvae." Aedes females lay above the waterline, the eggs "stick to container walls like glue," and they "can survive drying out for up to 8 months." **Do ultrasonic repellers or bug zappers reduce mosquito bites?** The published evidence says no. A Cochrane review of ten field studies concluded that electronic mosquito repellents "have no effect on preventing mosquito bites." A 1996 Entomological News survey found biting flies were 0.22 percent of insects killed by suburban electric traps, and called them "worthless for biting fly reduction." **What about a pond or rain barrel I cannot empty?** The CDC says to use larvicides on standing water that will not be used for drinking and cannot be covered, dumped, or removed, naming rain barrels, ornamental ponds, septic tanks, and unused pools. Follow the label, and do not apply more or more often than directed. If you get sick after mosquito exposure, the CDC's advice is to talk to a healthcare provider. **What can you put in standing water to stop mosquitoes?** A larvicide. EPA's homeowner option is Bti, the soil bacterium described in the section above, and EPA says larvicides "target larvae in the breeding habitat before they can mature into adult mosquitoes and disperse." EPA says Bti "can be used around homes in areas and containers where water can collect, such as flower pots, tires, and bird baths," and "to treat larger bodies of water like ponds, lakes and irrigation ditches." Read the label: EPA says "some are allowed to be used on certain drinking water (e.g., cisterns) while others are not intended for that use," and the CDC's dunks-and-bits rules sit in the section above on water you cannot dump. **Are mosquito dunks a risk to people or pets?** EPA's statements are about Bti, the larvicide the CDC lists first for dunks and bits, not about any particular product. EPA says Bti "has no toxicity to people," that "EPA has concluded that Bti does not pose a risk to humans," and that "people do not need to leave areas being treated." For pets, the National Pesticide Information Center's Bt fact sheet says "pets and people might be exposed to Bt from treated birdbaths or water fountains," that you "can limit exposure and reduce risk by carefully following the label instructions," and that people and other mammals "do not have the specific enzymes that break down the spore proteins to release the toxins" and lack "the necessary receptors that insect guts have." NPIC's pointer is the label; for a pet that has been drinking from a treated birdbath, ask your veterinarian. ### Related reading - [West Nile Virus in NYC, 2026](https://longsleeve.com/blog/west-nile-virus-nyc). The 2026 borough counts, the September spray schedule, and where 311 fits. - [Aedes aegypti: The Yellow Fever Mosquito](https://longsleeve.com/blog/aedes-aegypti). The day-biting container breeder behind dengue and Zika. - [When Is Mosquito Season?](https://longsleeve.com/blog/mosquito-season-by-region). Health-department months and temperature thresholds, region by region. - [The Asian Tiger Mosquito](https://longsleeve.com/blog/asian-tiger-mosquito). A daytime biter that breeds in whatever holds water. - [West Nile Virus in the United States](https://longsleeve.com/blog/west-nile-virus). The bird cycle, the late-summer peak, and who is actually at risk. - [The almanac of biting insects](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. - [Do Ultrasonic Repellers Work?](https://longsleeve.com/blog/ultrasonic-repellers). The gadget that keeps getting sold, and the evidence against it. More Longsleeve in your Google feed: ### Sources 1. CDC, Mosquito Control at Home. [https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-at-home.html](https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-at-home.html) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC, Life Cycle of *Aedes* Mosquitoes. [https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html](https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html) 1. CDC, About *Culex* Mosquitoes. [https://www.cdc.gov/mosquitoes/about/culex-mosquitoes.html](https://www.cdc.gov/mosquitoes/about/culex-mosquitoes.html) 1. CDC, Where Mosquitoes Live. [https://www.cdc.gov/mosquitoes/about/where-mosquitoes-live_1.html](https://www.cdc.gov/mosquitoes/about/where-mosquitoes-live_1.html) 1. CDC, Larvicides. [https://www.cdc.gov/mosquitoes/mosquito-control/larvicides.html](https://www.cdc.gov/mosquitoes/mosquito-control/larvicides.html) 1. CDC, Mosquito Control: What You Need to Know About Bti (PDF). [https://www.cdc.gov/mosquitoes/pdfs/bti-508.pdf](https://www.cdc.gov/mosquitoes/pdfs/bti-508.pdf) 1. CDC, Mosquito Control in a Community. [https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-in-a-community.html](https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-in-a-community.html) 1. CDC, About West Nile Virus. [https://www.cdc.gov/west-nile-virus/about/index.html](https://www.cdc.gov/west-nile-virus/about/index.html) 1. EPA, Mosquito Life Cycle. [https://www.epa.gov/mosquitocontrol/mosquito-life-cycle](https://www.epa.gov/mosquitocontrol/mosquito-life-cycle) 1. EPA, Success in Mosquito Control: An Integrated Approach. [https://www.epa.gov/mosquitocontrol/success-mosquito-control-integrated-approach](https://www.epa.gov/mosquitocontrol/success-mosquito-control-integrated-approach) 1. EPA, Bti for Mosquito Control. [https://www.epa.gov/mosquitocontrol/bti-mosquito-control](https://www.epa.gov/mosquitocontrol/bti-mosquito-control) 1. EPA, Pesticide Devices: A Guide for Consumers. [https://www.epa.gov/pesticides/pesticide-devices-guide-consumers](https://www.epa.gov/pesticides/pesticide-devices-guide-consumers) 1. National Pesticide Information Center, *Bacillus thuringiensis* (Bt). [http://npic.orst.edu/ingred/bt.html](http://npic.orst.edu/ingred/bt.html) 1. Enayati A, Hemingway J, Garner P. Electronic mosquito repellents for preventing mosquito bites and malaria infection. Cochrane Database of Systematic Reviews 2007, Issue 2. Art. No.: CD005434. [https://www.cochrane.org/evidence/CD005434_electronic-mosquito-repellents-preventing-mosquito-bites-and-malaria-infection](https://www.cochrane.org/evidence/CD005434_electronic-mosquito-repellents-preventing-mosquito-bites-and-malaria-infection) 1. Frick TB, Tallamy DW. Density and Diversity of Nontarget Insects Killed by Suburban Electric Insect Traps. Entomological News, 1996;107(2):77-82. [https://archive.org/details/biostor-76681](https://archive.org/details/biostor-76681) 1. Rodriguez SD, et al. Efficacy of Some Wearable Devices Compared with Spray-On Insect Repellents for the Yellow Fever Mosquito, *Aedes aegypti* (L.) (Diptera: Culicidae). Journal of Insect Science, 2017. DOI: 10.1093/jisesa/iew117. [https://pubmed.ncbi.nlm.nih.gov/28423421/](https://pubmed.ncbi.nlm.nih.gov/28423421/) 1. EPA, Tips to Prevent Mosquito Bites, last updated May 11, 2026. [https://www.epa.gov/insect-repellents/tips-prevent-mosquito-bites](https://www.epa.gov/insect-repellents/tips-prevent-mosquito-bites) 1. EPA, Controlling Mosquitoes at the Larval Stage, last updated February 26, 2026. [https://www.epa.gov/mosquitocontrol/controlling-mosquitoes-larval-stage](https://www.epa.gov/mosquitocontrol/controlling-mosquitoes-larval-stage) 1. National Pesticide Information Center, Bacillus thuringiensis (Bt) General Fact Sheet, reviewed May 2022. [http://npic.orst.edu/factsheets/btgen.html](http://npic.orst.edu/factsheets/btgen.html) Last reviewed 2026-08-06 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Tick Identification Guide: Species, Pictures, Regions, and Risks URL: https://longsleeve.com/blog/tick-identification > What a tick looks like up close: eight legs on nymphs and adults, six on larvae, size by life stage, engorged ticks, and the bugs people mistake for ticks. Source: https://longsleeve.com/blog/tick-identification By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 5, 2026 · Updated September 3, 2026 **Short answer:** Identify a tick by its mouthparts, scutum, color pattern, size, life stage, and where you found it. In U.S. human-biting records, blacklegged ticks, lone star ticks, American dog ticks, western blacklegged ticks, and Rocky Mountain wood ticks account for most hard ticks reported on people. If you saved the tick, species and engorgement can help a clinician assess risk. ### What does a tick look like? Cornell's Integrated Pest Management program describes ticks as arachnids, closely related to mites and spiders, flattened and teardrop shaped when unfed. The University of Maine's Tick Lab adds that they are often mistaken for insects, and that nymphs and adults have eight legs. The University of Rhode Island's TickEncounter program lists what an adult tick has: eight legs, two body regions, and no antennae. The University of Maine's Tick Lab describes two parts: a head, the capitulum, and a flattened oval body, the idiosoma. Virginia's health department says ticks are identified by the shape of the mouthparts and the scutum, along with colors and patterning. On hard ticks the scutum is a hardened plate on the back, sitting just behind the head on an adult female blacklegged tick. It covers about a third of a female's back and helps tell species apart; on a male it covers the whole back. Identification is step one; our guide to [permethrin-treated clothing](https://longsleeve.com/blog/permethrin-clothing) covers the follow through. ### How many legs do ticks have? Eight if the tick is a nymph or an adult, six if it is a larva. The [CDC](https://www.cdc.gov/ticks/about/tick-lifecycles.html) describes four life stages for most ticks: egg, six-legged larva, eight-legged nymph, and adult. Like spiders and other arachnids, adult ticks and nymphs have eight legs, while larvae emerge from the egg with only six. That is why the count changes with age. The six-legged larva, sometimes called a seed tick, hatches and seeks out its first host. The nymph that follows has eight legs and is about the size of a poppy seed, small enough to be easily overlooked. ### How big is a tick? It depends on the life stage and on whether the tick has fed. The [CDC](https://www.cdc.gov/lyme/causes/index.html) puts adult blacklegged ticks at approximately the size of a sesame seed and nymphs at approximately the size of a poppy seed, and Cornell's Integrated Pest Management program notes that a fully fed adult female blacklegged or lone star tick can be as large as a raisin. The table puts the stages side by side. | Life stage | Legs | Size when unfed | Size when fed | |---|---|---|---| | Larva | Six (CDC; University of Maine Tick Lab) | Sometimes called a seed tick (University of Maine Tick Lab); no measurement in our sources | Abdomen expands after feeding (Cornell IPM); no size given in our sources | | Nymph | Eight (CDC; Cornell IPM) | About the size of a poppy seed, small enough to be easily overlooked (CDC; Cornell IPM). Blacklegged nymphs are less than 1/16 inch long (Virginia Department of Health) | Abdomen expands after feeding (Cornell IPM); no size given in our sources | | Adult | Eight (CDC; University of Maine Tick Lab) | About the size of a sesame seed for blacklegged ticks (CDC) | A fully fed adult female blacklegged or lone star tick can be as large as a raisin (Cornell IPM) | Species shifts the scale too. In the Minnesota Department of Health's side by side photo, the blacklegged tick is much smaller than the American dog tick, and the lone star tick is a little smaller than the American dog tick but larger than the blacklegged tick. ### What do you actually look at to identify a tick? The Virginia Department of Health puts it plainly: ticks can be identified by looking at certain characters, like the shape of their mouthparts and their scutum, along with colors and patterning. A review in *Clinical Microbiology Reviews* gives the genus-level characters for hard ticks: mouthpart length relative to the basis capituli, eyes present or absent, festoons present or absent, and markings on the dorsal shield. The same review describes *Ixodes* ticks by their elongated mouthparts, absence of eyes and festoons, and plain unmarked dorsal shield. *Dermacentor* ticks have relatively short mouthparts, eyes and festoons, and an ornate patterned shield. *Amblyomma* ticks have eyes, festoons, an ornate shield, and palps longer than the basis capituli. Mouthparts settle the most common mix-up. Virginia's health department distinguishes the American dog tick by its short, rounded mouthparts and the similar-looking Gulf Coast tick by its long, rectangular ones. On an adult female blacklegged tick the scutum is black and the body behind it is red-brown; Minnesota's health department calls that coloring reddish-orange. Adult males are dark brown or black and resemble a small watermelon seed. Size helps, but only in comparison: blacklegged ticks are much smaller than American dog ticks, and lone star ticks sit in between. ### Which ticks bite people in the United States? A 2022 review in *Ticks and Tick-borne Diseases* compiled published records of ticks collected while biting humans or crawling on skin or clothing in the U.S.: 36 hard tick species (234,722 specimens) and 13 soft tick species (230 specimens). The top five hard ticks recorded from humans were the blacklegged tick (158,008 specimens), the lone star tick (36,004), the American dog tick (26,624), the western blacklegged tick (4,158), and the Rocky Mountain wood tick (3,518). The brown dog tick (714) and Gulf Coast tick (335) also cleared 250 records. #### Blacklegged tick (*Ixodes scapularis*) Widely distributed across the eastern United States. Adult female: black scutum, red-brown body behind it. Transmits *Borrelia burgdorferi* and *B. mayonii* (Lyme disease), *Anaplasma phagocytophilum* (anaplasmosis), *Babesia microti* (babesiosis), *B. miyamotoi*, *Ehrlichia muris eauclairensis* (ehrlichiosis), and Powassan virus. The [CDC](https://www.cdc.gov/ticks/data-research/facts-stats/blacklegged-tick-surveillance.html) says the greatest risk of being bitten is in spring, summer, and fall, though adults may be searching for a host any time winter temperatures are above freezing. All life stages bite humans, but nymphs and adult females are most commonly found on people. #### Western blacklegged tick (*Ixodes pacificus*) Found along the Pacific coast, particularly northern California. Larvae and nymphs often feed on lizards, birds, and rodents; adults more commonly feed on deer. Transmits *Anaplasma phagocytophilum*, *Borrelia burgdorferi*, and very likely *B. miyamotoi*. Nymphs and adult females are more often reported on people, but larvae also bite people. #### Lone star tick (*Amblyomma americanum*) Widely distributed in the Northeast, South, and Midwest, and more common in the South. The adult female carries a single white dot, the "lone star," which Virginia's health department places at the center of her back. The [CDC](https://www.cdc.gov/ticks/data-research/facts-stats/lone-star-tick-surveillance.html) calls the species a very aggressive tick that bites humans, and says nymphs and adult females most frequently bite people and spread disease. It transmits Bourbon virus, *Ehrlichia chaffeensis* and *E. ewingii* (ehrlichiosis), Heartland virus, and tularemia. A circular rash of unknown cause (STARI) sometimes follows its bite, and growing evidence suggests alpha-gal syndrome, a red meat allergy, may be triggered by lone star tick bites. Its saliva can be irritating, so redness at a bite site does not necessarily mean infection. #### American dog tick (*Dermacentor variabilis*, *D. similis*) *D. variabilis* is widely distributed east of the Rocky Mountains and occurs in limited areas west of them. The newly described *D. similis*, recognized as a separate species in 2021, is found west of the Rockies, and more research is needed to understand the role of these species in disease transmission. Short, rounded mouthparts, ornate shield. Transmits tularemia and Rocky Mountain spotted fever. Highest bite risk is spring and summer, and adult females are most likely to bite people. Virginia's chart notes that only the adult stage is known to bite humans; nationally, adults were 99.6 percent of specimens recorded from people. #### Rocky Mountain wood tick (*Dermacentor andersoni*) Rocky Mountain states and southwestern Canada, at elevations from 4,000 to 10,500 feet. Adults feed primarily on large mammals; larvae and nymphs feed on small rodents. Transmits Rocky Mountain spotted fever, Colorado tick fever, and tularemia. Adults were 99.6 percent of specimens recorded from people, and adult and nymphal ticks are primarily associated with pathogen transmission to humans. #### Gulf Coast tick (*Amblyomma maculatum*) Primarily southeastern U.S., with focal populations in the Northeast, Midwest, and Southwest. Long, rectangular mouthparts separate it from the American dog tick. Larvae and nymphs feed on birds and small rodents, while adults feed on deer and other wildlife. Transmits *Rickettsia parkeri* rickettsiosis, a form of spotted fever, and adults are the stage associated with that transmission; adults were 94 percent of the specimens recorded from people. #### Brown dog tick (*Rhipicephalus sanguineus*) Found worldwide, and the one tick here that occurs in Hawaii. Dogs are its primary host at every life stage, and it prefers to feed on the same host throughout, but it will bite humans and other mammals. It is the primary vector for Rocky Mountain spotted fever in the southwestern U.S. and along the U.S.-Mexico border. Michigan's health department notes it can uniquely survive and breed in indoor environments and has been associated with kennel, shelter, and breeding facilities. #### Two more worth knowing The Asian longhorned tick (*Haemaphysalis longicornis*) was reported in the United States for the first time in 2017. Compared with well-known native ticks, the CDC says it appears less attracted to humans. Its identifying trait is behavioral: females can lay eggs and reproduce without mating, so thousands may turn up at once in grass or shrubs or on an animal. Soft ticks (*Ornithodoros*) transmit soft tick relapsing fever, usually in mountainous areas of western states and parts of Texas, most often when people stay overnight in rodent-infested cabins. You will probably never notice one. The [CDC](https://www.cdc.gov/relapsing-fever/about/about-strf.html) says bites from soft ticks are brief, usually lasting less than half an hour, and painless, and that most people are unaware they have been bitten. ### What can be mistaken for a tick? Weevils, bed bugs, and pseudoscorpions are the look-alikes our sources name, and one rule settles most cases: count the legs and look for antennae. The University of Rhode Island's TickEncounter program notes that a larger, adult stage tick has eight legs, two body regions, and no antennae. The weevil the program shows as a look-alike has six legs, three body regions, and a pair of clubbed antennae. Cornell's Integrated Pest Management program adds that an unfed tick is flattened and teardrop shaped. TickEncounter's field guide points to a common weevil that many people mistake for a tick; it shows six legs, three body regions, and a pair of clubbed antennae. Bed bugs turn up too, and TickEncounter notes that antennae and a segmented abdomen are things ticks do not have. The calibration is worth knowing: TickEncounter reports that about one in 20 crowdsourced submissions to its TickSpotters service is not a tick at all but a look-alike. Pseudoscorpions are arachnids, related to spiders, ticks, mites, and scorpions, with oval or teardrop shaped, flattened bodies and two conspicuous pincers. The University of Minnesota Extension says that without those large pincers, pseudoscorpions look like ticks. They are harmless to people and pets and cannot bite or sting. ### How do you tell a larva, nymph, and adult apart? Count the legs first. Most ticks go through four life stages: egg, six-legged larva, eight-legged nymph, and adult. Then judge size: the CDC puts adult blacklegged ticks at approximately the size of a sesame seed and nymphs at approximately the size of a poppy seed. The CDC notes that nymphal ticks pose a particularly high risk because of their abundance and small size, which makes them difficult to see, while adult females are more likely to be noticed and removed before transmission. In areas of the eastern United States where Lyme disease cases are common, nymphs are actively questing from April through July, and adults are most active in early spring and fall. ### How do you tell if a tick is engorged? The body swells and rounds out, and size comparisons stop working. Cornell's Integrated Pest Management program notes that tick abdomens expand after feeding, making identification difficult for most people, and that a fully fed adult female blacklegged or lone star tick can be as large as a raisin. Unfed, the CDC puts an adult blacklegged tick at about the size of a sesame seed and a nymph at about a poppy seed; Virginia's health department measures blacklegged nymphs at less than 1/16 of an inch. The tell that survives the swelling is the scutum: the University of Rhode Island's TickEncounter program notes it stays the same size no matter how big the tick grows during feeding. A small hard shield on a large, rounded body is a fed tick. If the tick is still attached, start with our [tick removal guide](https://longsleeve.com/blog/tick-removal), which covers the CDC method, and hang on to the tick. Virginia's health department says that if you start to become sick after a tick bite, knowing what type of tick it was may help you and your healthcare team discuss testing and treatment options. Our guide to [Lyme disease prevention](https://longsleeve.com/blog/lyme-disease-prevention) picks up from there. The [CDC](https://www.cdc.gov/ticks/after-a-tick-bite/index.html)'s rule is plain: a rash or fever within several days to weeks after removing a tick means see your doctor. ### How do you narrow it down by where you live? Geography rules species out fast. The [CDC](https://www.cdc.gov/ticks/about/where-ticks-live.html) notes that naturally occurring populations of the tick species it maps do not occur in Alaska, though the brown dog tick occurs in Hawaii. One further caution from the CDC: even though a species is found in a region, that does not necessarily mean it transmits a specific disease there. Blacklegged ticks in most areas of the southeastern United States are almost never infected with Lyme disease bacteria. In Minnesota, by contrast, the state health department reports that on average about 1 in 3 adult blacklegged ticks and 1 in 5 nymphs carries it. ### Does knowing the species change what you should do? Species changes what you watch for afterward, but the first step is the same either way: remove the tick right away. The CDC says to grasp it as close to the skin's surface as possible with clean fine-tipped tweezers and pull away with steady, even pressure, without twisting or jerking. Do not use petroleum jelly, heat, or nail polish to make it detach. Species knowledge matters at the doctor's office. As Virginia's health department puts it, if you start to become sick after a tick bite, knowing what type of tick it was may help you and your healthcare team discuss testing and treatment options. If you develop a rash or fever within several days to weeks after removing a tick, see your doctor. ### How do you keep ticks off in the first place? Tick exposure can occur year-round, but the [CDC](https://www.cdc.gov/ticks/prevention/index.html) notes ticks are most active during warmer months, April through September. The CDC recommends treating clothing and gear with products containing 0.5% permethrin, and using EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone, looking for an EPA registration number on the label. Back indoors, the CDC says to check under the arms, in and around the ears, behind the knees, in your hair, and around the waist. Showering within two hours of coming indoors has been shown to reduce Lyme disease risk. ### About Longsleeve Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients. ### Tick identification FAQ **Should I send the tick off to be tested?** The CDC says commercial tick testing is in general not recommended, and that results of tick testing should not be used for treatment decisions. Knowing the species is still useful: Virginia's health department notes it may help you and your healthcare team discuss options if you become sick. **Which tick has a white spot on its back?** The adult female lone star tick. The CDC says she is distinguished by a white dot or "lone star" on her back, which Virginia's health department places at the center of her back. **How long does a tick have to be attached to transmit Lyme disease?** The CDC states that in general, infected ticks must be attached for more than 24 hours to transmit infection, and that prompt removal can prevent transmission. **Can any tick give me Lyme disease?** The CDC says Lyme disease bacteria causing human infection in the United States are spread to people by blacklegged ( Ixodes ) ticks: the blacklegged tick in the northeastern, mid-Atlantic, and north-central states, and the western blacklegged tick along the Pacific Coast. Other species carry other pathogens, which is why exposure history is worth reporting to a clinician. **Is a tick an insect?** No. Ticks are arachnids, closely related to mites and spiders. The University of Maine's Tick Lab notes they are often mistaken for insects even though they belong, with mites, to the subclass Acari. The University of Rhode Island's TickEncounter program gives an adult tick's characters as eight legs, two body regions, and no antennae. ### Related reading - [The Lone Star Tick](https://longsleeve.com/blog/lone-star-tick). The white-dot tick, its range, and the illnesses the CDC links to its bite. - [Ehrlichiosis: The Lone Star Tick's Signature Illness](https://longsleeve.com/blog/ehrlichiosis). The lone star tick's signature illness, in CDC numbers. - [Alpha-Gal Syndrome](https://longsleeve.com/blog/alpha-gal-syndrome). The lone star tick bite that can trigger a red meat allergy. - [When Is Tick Season?](https://longsleeve.com/blog/tick-season-when). Why nymphs drive most disease, and why checks matter year round. - [Our field guide to biting insects](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. CDC, Where Ticks Live. [https://www.cdc.gov/ticks/about/where-ticks-live.html](https://www.cdc.gov/ticks/about/where-ticks-live.html) 1. CDC, Tick Lifecycles. [https://www.cdc.gov/ticks/about/tick-lifecycles.html](https://www.cdc.gov/ticks/about/tick-lifecycles.html) 1. CDC, Blacklegged Tick Surveillance. [https://www.cdc.gov/ticks/data-research/facts-stats/blacklegged-tick-surveillance.html](https://www.cdc.gov/ticks/data-research/facts-stats/blacklegged-tick-surveillance.html) 1. CDC, Western Blacklegged Tick Surveillance. [https://www.cdc.gov/ticks/data-research/facts-stats/western-blacklegged-tick-surveillance.html](https://www.cdc.gov/ticks/data-research/facts-stats/western-blacklegged-tick-surveillance.html) 1. CDC, American Dog Tick Surveillance. [https://www.cdc.gov/ticks/data-research/facts-stats/american-dog-tick-surveillance.html](https://www.cdc.gov/ticks/data-research/facts-stats/american-dog-tick-surveillance.html) 1. CDC, Lone Star Tick Surveillance. [https://www.cdc.gov/ticks/data-research/facts-stats/lone-star-tick-surveillance.html](https://www.cdc.gov/ticks/data-research/facts-stats/lone-star-tick-surveillance.html) 1. CDC, How Lyme Disease Spreads. [https://www.cdc.gov/lyme/causes/index.html](https://www.cdc.gov/lyme/causes/index.html) 1. CDC, What to Do After a Tick Bite. [https://www.cdc.gov/ticks/after-a-tick-bite/index.html](https://www.cdc.gov/ticks/after-a-tick-bite/index.html) 1. CDC, Preventing Tick Bites. [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. CDC, About Soft Tick Relapsing Fever (STRF). [https://www.cdc.gov/relapsing-fever/about/about-strf.html](https://www.cdc.gov/relapsing-fever/about/about-strf.html) 1. CDC, Tickborne Diseases of the United States: A Reference Manual for Healthcare Providers (PDF). [https://www.cdc.gov/ticks/media/pdfs/2025/03/tickborne-diseases-manual-508.pdf](https://www.cdc.gov/ticks/media/pdfs/2025/03/tickborne-diseases-manual-508.pdf) 1. Eisen L. Tick species infesting humans in the United States. Ticks and Tick-borne Diseases, 13(6), 2022. [https://pmc.ncbi.nlm.nih.gov/articles/PMC10862467/](https://pmc.ncbi.nlm.nih.gov/articles/PMC10862467/) 1. Mathison BA, Pritt BS. Laboratory Identification of Arthropod Ectoparasites. Clinical Microbiology Reviews, 27(1):48-67, 2014. [https://pmc.ncbi.nlm.nih.gov/articles/PMC3910909/](https://pmc.ncbi.nlm.nih.gov/articles/PMC3910909/) 1. Virginia Department of Health, Tick Identification. [https://www.vdh.virginia.gov/ticks/tick-identification/](https://www.vdh.virginia.gov/ticks/tick-identification/) 1. Virginia Department of Health, Tick Identification Chart (PDF). [https://www.vdh.virginia.gov/content/uploads/sites/6/2024/04/Digital-Tick-Identification-Chart.pdf](https://www.vdh.virginia.gov/content/uploads/sites/6/2024/04/Digital-Tick-Identification-Chart.pdf) 1. Minnesota Department of Health, Ticks. [https://www.health.state.mn.us/diseases/tickborne/ticks.html](https://www.health.state.mn.us/diseases/tickborne/ticks.html) 1. Michigan Department of Health and Human Services, Michigan's Five Most Common Ticks (PDF). [https://www.michigan.gov/-/media/Project/Websites/emergingdiseases/Folder2/5commonticks.pdf](https://www.michigan.gov/-/media/Project/Websites/emergingdiseases/Folder2/5commonticks.pdf) 1. Cornell University Integrated Pest Management, Tick Biology. [https://cals.cornell.edu/integrated-pest-management/outreach-education/whats-bugging-you/ticks/tick-biology](https://cals.cornell.edu/integrated-pest-management/outreach-education/whats-bugging-you/ticks/tick-biology) 1. University of Maine Cooperative Extension Tick Lab, Tick Biology. [https://extension.umaine.edu/ticks/tick-biology/](https://extension.umaine.edu/ticks/tick-biology/) 1. University of Rhode Island TickEncounter Resource Center, Is It a Tick?. [https://web.uri.edu/tickencounter/fieldguide/is-it-a-tick/](https://web.uri.edu/tickencounter/fieldguide/is-it-a-tick/) 1. University of Rhode Island TickEncounter Resource Center, Tick Growth Comparison Charts. [https://web.uri.edu/tickencounter/fieldguide/tick-growth-comparison-charts/](https://web.uri.edu/tickencounter/fieldguide/tick-growth-comparison-charts/) 1. University of Minnesota Extension, Pseudoscorpions. [https://extension.umn.edu/insect-relatives/pseudoscorpions](https://extension.umn.edu/insect-relatives/pseudoscorpions) Last reviewed 2026-08-05 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## How to Remove a Tick: Tweezers, Timing, and What Not to Do URL: https://longsleeve.com/blog/tick-removal > CDC tick removal steps: use fine-tipped tweezers, pull steadily, avoid heat, nail polish, and petroleum jelly, clean the bite, and watch for fever or rash. Source: https://longsleeve.com/blog/tick-removal By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 5, 2026 · Updated August 16, 2026 **Short answer:** To remove a tick, the CDC says to use clean fine-tipped tweezers, grasp the tick as close to the skin as possible, and pull away with steady, even pressure. Do not twist, jerk, burn it, cover it with petroleum jelly, or use nail polish. Clean the bite and your hands afterward, then watch for fever or rash over the next several weeks. That is the whole procedure, and you almost certainly already own the tool. The details below matter because the two things that go wrong are waiting and trying to make the tick let go on its own, and the CDC warns against both. ### What is the correct way to remove a tick? The CDC's instruction is to remove an attached tick as soon as you find it, and specifically not to wait for a medical appointment to do it. In the agency's words, "Delaying tick removal to get help from a healthcare provider could increase your risk of getting a disease spread through tick bites." You do not need a special gadget either. The [CDC](https://www.cdc.gov/ticks/after-a-tick-bite/index.html) notes that there are several tick removal devices on the market, but that a plain set of tweezers works very well. 1. **Grasp the tick as close to the skin's surface as possible** using clean fine-tipped tweezers. If you do not have fine-tipped tweezers, the CDC says regular tweezers or your fingers will do. Getting close to the skin is what keeps you from squeezing the tick's body. 1. **Pull the tick away from the skin with steady, even pressure.** Do not twist. Do not jerk. According to the CDC, that is what causes the mouthparts to break off and stay in the skin. 1. **Dispose of the live tick** by putting it in a sealed container, wrapping it tightly in tape, flushing it down the toilet, or putting it in alcohol. The CDC says not to crush it with your fingers. 1. **Clean the bite area and your hands** thoroughly with soap and water, rubbing alcohol, or hand sanitizer. 1. **Look for more ticks.** The CDC's point here is simple: if one tick found you, others may have too. Do a careful check and remove any you find. ### What should you never do to a tick? The folk remedies all share the same logic, which is to irritate the tick until it backs out on its own. The CDC is direct about this: "Do not use petroleum jelly, heat, nail polish, or other substances to try and make the tick detach from the skin. This may agitate the tick and force infected fluid from the tick into the skin." So no heat, no nail polish, no household substance of any kind smeared on an attached tick. Every minute spent on that is a minute the tick stays attached, and by the CDC's account the attempt itself can force infected fluid into the skin. Twisting is the other common mistake, and the [CDC](https://www.cdc.gov/lyme/media/pdfs/Caring-for-Patients-after-a-Tick-Bite.pdf) gives the same instruction to the public and to clinicians: pull upward with steady, even pressure, and do not twist or jerk the tick. ### What if the mouthparts break off in the skin? This happens, and the CDC's instruction is not to fight it. The CDC says that if the mouthparts break off and remain in the skin, "your body will naturally push the mouthparts out over time as your skin heals." You can try to remove them with tweezers. If they do not come out easily, the CDC says to leave them alone. The instruction is to stop, not to keep digging. ### Should you save the tick? Saving it and testing it are two different things, and the CDC treats them differently. Saving it can be useful. The CDC's clinician guidance recommends killing a live tick by putting it in rubbing alcohol or placing it in a sealed bag or container, and saving the tick "for species identification and degree of tick engorgement," which the guidance notes is important when determining eligibility for Lyme disease prophylaxis. A tick in a sealed bag gives your doctor the two things that guidance names: the species, and the degree of engorgement. Sending it to a lab is a different story. The CDC does not recommend commercial tick testing, for four reasons it spells out: labs that test ticks are not required to meet the quality control standards of clinical diagnostic labs, and their results should not drive treatment decisions; a positive result does not necessarily mean you were infected; a negative result can create false assurance, because you may have been bitten by a different, infected tick without noticing; and if you were infected, you will probably develop symptoms before the test results come back. The CDC adds that if you do become ill, you should not wait for tick testing results before beginning appropriate treatment. ### How long does a tick have to be attached to transmit disease? For Lyme disease, the [CDC](https://www.cdc.gov/lyme/causes/index.html) states that in most cases a tick must be attached for more than 24 hours before the bacterium can be transmitted, and that removing a tick within 24 hours greatly reduces your chances of getting Lyme disease. That is the entire argument for checking your body every time you come in from outside. The reason people miss the window is that an attached tick is easy not to notice. The [CDC](https://www.cdc.gov/ticks/about/index.html) explains that ticks secrete small amounts of saliva with anesthetic properties, "so that the animal or person can't feel that the tick has attached itself," and that a tick in a sheltered spot can go unnoticed. Size does not help either. The CDC describes nymphal blacklegged ticks as roughly the size of a poppy seed and adults as roughly the size of a sesame seed. ### When should you see a doctor after a tick bite? The CDC's follow-up rule is short: if you develop a rash or fever within several weeks of removing a tick, see your doctor. Tell them about the recent tick bite, when the bite occurred, and where you most likely picked up the tick. Location matters: the CDC's clinician guidance says location of tick exposure can guide the differential diagnosis. The most common symptoms of tick-related illness, per the CDC, are fever and chills, aches and pains including headache, fatigue and muscle aches, and rash. People with Lyme disease may also have joint pain. On the Lyme rash specifically: the [CDC](https://www.cdc.gov/lyme/signs-symptoms/index.html) says the erythema migrans rash occurs in approximately 70 to 80 percent of infected people, begins at the bite site after a delay of 3 to 30 days with an average of about 7 days, expands gradually to 12 inches or more across, may feel warm but is rarely itchy or painful, and does not always look like a classic bull's-eye. Worth knowing the difference from a normal reaction: the CDC notes that a small bump or redness at the bite site that appears immediately and resembles a mosquito bite is common, generally goes away in one to two days, and is not a sign of Lyme disease. Some tickborne illnesses move fast. The [CDC](https://www.cdc.gov/rocky-mountain-spotted-fever/about/index.html) states that Rocky Mountain spotted fever can be deadly if not treated early with doxycycline, and that its rash usually develops 2 to 4 days after the fever begins, which means the rash often shows up late in the illness. The CDC's clinician guidance says that when acute tickborne disease is suspected, including early Lyme disease or Rocky Mountain spotted fever, treatment should start as soon as possible rather than waiting for laboratory results that may be insensitive early on. There is also a timing question worth raising with your doctor. The CDC's clinician guidance describes post-exposure prophylaxis for Lyme disease, a single dose of doxycycline that can lower risk in certain circumstances, and notes that prophylaxis can be started within 72 hours of tick removal. The same guidance is clear that antibiotic prophylaxis has not been shown to prevent tickborne diseases other than Lyme, and is not recommended for anaplasmosis, babesiosis, ehrlichiosis, or Rocky Mountain spotted fever. That is a conversation for a clinician, not a decision to make from a blog post. ### How do you avoid the next one? The CDC's prevention guidance is mostly about routine. Treat clothing and gear with products containing 0.5% permethrin, which stays protective through several washings. Use EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone, and look for the EPA registration number on the label. Walk in the center of trails and avoid high grass and leaf litter. When you come back inside, the CDC recommends checking your clothing, tumble drying dry clothes on high heat for 10 minutes to kill any ticks on them, showering within two hours, which it says has been shown to reduce the risk of getting Lyme disease, and doing a full body check. The spots the [CDC](https://www.cdc.gov/ticks/prevention/index.html) says to check: under the arms, in and around the ears, inside the belly button, the back of the knees, in and around the hair, between the legs, and around the waist. Tick exposure can happen year-round, though the CDC says ticks are most active during the warmer months of April through September. ### About Longsleeve Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients. None of this replaces medical advice. If you pulled a tick off and something feels wrong afterward, call your doctor and tell them about the bite. ### Common questions **Do I need a special tick removal tool?** No. The CDC says that although there are several tick removal devices on the market, a plain set of tweezers works very well. Fine-tipped tweezers are ideal, but the CDC says regular tweezers or your fingers can be used if that is what you have. **Can I burn the tick off or smother it with Vaseline?** No. The CDC says not to use petroleum jelly, heat, nail polish, or other substances to make a tick detach, because it may agitate the tick and force infected fluid from the tick into the skin. **Should I send the tick to a lab to be tested?** The CDC does not recommend it. Tick testing labs are not held to clinical diagnostic standards, a positive result does not mean you were infected, a negative result can give false assurance, and you would likely develop symptoms before results arrive. Saving the tick for identification is still useful for your doctor. **What if I never see a rash but feel sick?** Still call your doctor. The CDC lists fever and chills, headache, fatigue, and muscle aches among the most common symptoms of tick-related illness, and says these can occur with Lyme disease in the absence of a rash. ### Related reading - [Insect Repellent for Hiking and Backpacking](https://longsleeve.com/blog/insect-repellent-for-hiking). Gear, trailhead, trail, and the back-at-camp routine. - [Insect Repellent and Children](https://longsleeve.com/blog/mosquito-repellent-for-kids). What the CDC and AAP actually say about repellent on kids. - [Lyme Disease Prevention](https://longsleeve.com/blog/lyme-disease-prevention). Transmission, the attachment window, and the layers that lower risk. - [Tick Identification Guide](https://longsleeve.com/blog/tick-identification). Which tick bit you, and what it can carry. - [The species almanac](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. CDC, What to Do After a Tick Bite. [https://www.cdc.gov/ticks/after-a-tick-bite/index.html](https://www.cdc.gov/ticks/after-a-tick-bite/index.html) 1. CDC, Don't Wait: Remove Attached Ticks ASAP (Tick Removal Fact Sheet, PDF). [https://www.cdc.gov/ticks/media/pdfs/2025/07/CDC_TickRemovalFactSheet.pdf](https://www.cdc.gov/ticks/media/pdfs/2025/07/CDC_TickRemovalFactSheet.pdf) 1. CDC, About Ticks and Tickborne Disease. [https://www.cdc.gov/ticks/about/index.html](https://www.cdc.gov/ticks/about/index.html) 1. CDC, Preventing Tick Bites. [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. CDC, How Lyme Disease Spreads. [https://www.cdc.gov/lyme/causes/index.html](https://www.cdc.gov/lyme/causes/index.html) 1. CDC, Signs and Symptoms of Untreated Lyme Disease. [https://www.cdc.gov/lyme/signs-symptoms/index.html](https://www.cdc.gov/lyme/signs-symptoms/index.html) 1. CDC, Guidance for Clinicians: Caring for Patients after a Tick Bite (PDF). [https://www.cdc.gov/lyme/media/pdfs/Caring-for-Patients-after-a-Tick-Bite.pdf](https://www.cdc.gov/lyme/media/pdfs/Caring-for-Patients-after-a-Tick-Bite.pdf) 1. CDC, About Rocky Mountain Spotted Fever. [https://www.cdc.gov/rocky-mountain-spotted-fever/about/index.html](https://www.cdc.gov/rocky-mountain-spotted-fever/about/index.html) Last reviewed 2026-08-05 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## When Is Tick Season? Months, Nymphs, Adults, and Regions URL: https://longsleeve.com/blog/tick-season-when > When tick season starts and peaks in the U.S., including CDC guidance on April through September activity, spring nymphs, fall adults, winter risk, and regional differences. Source: https://longsleeve.com/blog/tick-season-when By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 5, 2026 · Updated August 16, 2026 Ticks are most active from April through September, but exposure can happen year round. Nymphs quest from April through July and pose a particularly high risk. Adults are most active in early spring and fall, and blacklegged tick adults may search for a host any time winter temperatures rise above freezing. Most people picture tick season as one block on the calendar, roughly summer. A tick's biting season depends on which life stage is out hunting, and the stages take turns across the year. Get the stages straight and the calendar makes sense, including why the riskiest ticks arrive early. ### What months is tick season? The [CDC](https://www.cdc.gov/ticks/prevention/index.html) puts it plainly on its Preventing Tick Bites page: "Tick exposure can occur year-round, but ticks are most active during warmer months (April-September)." NIOSH, the CDC's occupational safety arm, frames the same window for outdoor workers: "Ticks may be active all year in some regions with warmer weather. In the United States, they are most active in the spring, summer, and fall." **Short answer:** CDC guidance says tick exposure can happen year-round, but ticks are most active during warmer months, April through September. For blacklegged ticks, nymphs quest from April through July and are high risk because they are small and easy to miss. Adults are most active in early spring and fall, and may search for a host any time winter temperatures are above freezing. ### Why do nymphs in late spring and summer matter most? Most ticks go through four life stages. The [CDC](https://www.cdc.gov/ticks/about/tick-lifecycles.html) describes them as "egg, six-legged larva, eight-legged nymph, and adult," and notes that after hatching, "ticks must eat blood at every stage to survive." The infection math follows from that feeding schedule. As the CDC puts it, "Ticks usually acquire pathogens early in their life (larval or nymphal stages) when they feed on animals. They transmit those pathogens to other animals or to people later in their life (nymphal or adult stages)." For the blacklegged tick, the species behind Lyme disease in the eastern United States, the [CDC](https://www.cdc.gov/lyme/causes/index.html) gives the timing directly: "From April through July, nymphs are actively questing for hosts in the environment, and in early spring and fall seasons, adults are most active." That April to July nymph window is the part worth circling. The CDC explains why: "Nymphal ticks pose a particularly high risk due to their abundance and small size (about the size of a poppy seed), which makes them difficult to see. Lyme disease patients are often not even aware of a tick bite before getting sick." Adult females can transmit the same bacteria, but per the CDC they "are more likely to be noticed and removed before transmission due to their larger size (about the size of sesame seed)." The case data lines up with the nymph calendar. The [CDC](https://www.cdc.gov/mmwr/volumes/66/ss/ss6622a1.htm) logged 275,589 reported Lyme disease cases from 2008 through 2015, and date of illness onset was available for 200,108 of them. Among those, "for all years, the first week in July was the peak week of illness onset for confirmed and probable cases." ### When are adult ticks active, and does fall count? Fall counts. The CDC's own surveillance authors made the point explicitly in that same report: the seasonal pattern "underscores that adult ticks that seek blood meal hosts during the fall months have a proportional role in human illness and that prevention messages should not be focused only during the spring and summer season when nymphal ticks seek hosts." That is a public health agency telling its own field not to shut off the message on Labor Day. The [CDC](https://www.cdc.gov/ticks/about/where-ticks-live.html)'s blacklegged tick page agrees: "the greatest risk of being bitten exists in the spring, summer, and fall," with nymphs and adult females the stages most likely to bite humans. ### Can you get a tick bite in winter? Yes, and the threshold is lower than most people expect. The CDC states that blacklegged tick adults "may be out searching for a host any time winter temperatures are above freezing." Its Lyme prevention page adds that "most cases of Lyme disease are reported in the summer months, though Lyme disease cases occur year-round." Field research gives a number. Duffy and Campbell, publishing in the Journal of Medical Entomology in 1994, ran winter flagging experiments on Long Island and reported that adult *Ixodes scapularis* "have an apparent threshold of questing activity at 4 degrees C," roughly 39 degrees Fahrenheit. Their conclusion was aimed squarely at public messaging: "This threshold should be incorporated into public education efforts because the public may be at risk of contracting Lyme disease any time during the winter when temperatures exceed 4 degrees C." A 40-degree January afternoon is not tick-free. Winter cases also look different clinically. In the CDC surveillance data, among patients with illness onset during the coldest months, December through March, arthritis was the most common clinical sign. Erythema migrans, the expanding rash, was the most common sign for onsets from April through November. ### Does tick season change depending on where you live? Substantially. Start with which ticks are even present. The CDC maps the blacklegged tick as "widely distributed across the eastern United States" and the western blacklegged tick "along the Pacific coast of the United States, particularly northern California." The American dog tick is "widely distributed east of the Rocky Mountains," the Gulf Coast tick sits "primarily in the southeastern United States," and the Rocky Mountain wood tick occupies "Rocky Mountain states and southwestern Canada from elevations of 4,000 to 10,500 feet." Then the calendars diverge. On the Pacific coast the pattern nearly inverts the eastern one. The California Department of Public Health reports that for the western blacklegged tick, "nymphs are most active in spring and early summer, and adult ticks are most active from fall through early spring." CDPH also notes that "risk of exposure varies throughout California," and that in some parts of the state a higher share of nymphs carry Lyme disease bacteria, an average of 5 to 15 percent, than adults, an average of 1 to 2 percent. Disease burden is regional too. The CDC's surveillance summary found that fourteen states in the Northeast, mid-Atlantic, and upper Midwest accounted for 95.2 percent of all reported Lyme disease cases during 2008 through 2015, and current CDC guidance still places most cases in those regions, with some on the Pacific Coast. ### Do other tick species follow the same calendar? No, and the lone star tick is the clearest example. Writing in the CDC journal Emerging Infectious Diseases in 2019, Telford and colleagues summarized its phenology: "Across their wide distribution south of New York, adult lone star ticks seek hosts mid-March through late June; nymphs, mid-May through late July; and larvae, July through September." Larvae, they wrote, "seem to feed mainly during late summer and early fall," with modeling suggesting a temperature threshold near 17 degrees Celsius, about 63 degrees Fahrenheit, for larval host seeking. That paper exists because the calendar moved. Dragging on June 7, 2018 on Long Island, New York and June 18, 2018 on Naushon Island, Massachusetts, the authors found larval clusters "reminiscent of those of lone star ticks typically encountered during August or September." The CDC calls [the lone star tick](https://longsleeve.com/blog/lone-star-tick) "a very aggressive tick that bites humans," widely distributed in the Northeast, South, and Midwest, with nymphs and adult females the stages that most frequently bite people. For the American dog tick, the CDC says "the highest risk of being bitten occurs during spring and summer," and adult females are the ones most likely to bite humans. ### What does the CDC recommend during tick season? The CDC's stated principle is that "reducing exposure to ticks is the best defense against tickborne diseases." Its recommendations include: - Use EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone, and look for an EPA registration number on the label. - Treat clothing and gear with products containing 0.5 percent permethrin, which the CDC says remains protective through several washings. - Avoid wooded and brushy areas with high grass and leaf litter, and walk in the center of trails. - Check your body for ticks after being outdoors, including under the arms, in and around the ears, inside the belly button, behind the knees, in and around the hair, between the legs, and around the waist. - Tumble dry clothes on high heat for 10 minutes to kill ticks on dry clothing after coming indoors. - Shower soon after being outdoors. The CDC says showering within two hours of coming indoors has been shown to reduce the risk of getting Lyme disease. - Remove attached ticks as soon as possible, and do not wait to see a healthcare provider to remove one. The CDC states that removing attached ticks within 24 hours can help prevent Lyme disease. This is not only a wilderness problem. The CDC notes that "many people get ticks in their own yard or neighborhood," and that many people who develop Lyme disease are exposed in their own yards rather than in wooded or rural areas. ### Where Longsleeve fits Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients. ### Common questions **When does tick season start?** The CDC says ticks are most active during warmer months, April through September, but that tick exposure can occur year-round. For blacklegged ticks, nymphs are actively questing from April through July, and adults are most active in early spring and fall. **Is there a temperature below which ticks stop biting?** The CDC says blacklegged tick adults may search for a host any time winter temperatures are above freezing. Research published in the Journal of Medical Entomology in 1994 found an apparent questing threshold of 4 degrees Celsius, about 39 degrees Fahrenheit, for adult Ixodes scapularis on Long Island. **Which life stage is riskiest?** The CDC says nymphal ticks pose a particularly high risk because of their abundance and their small size, about that of a poppy seed, which makes them hard to see. The California Department of Public Health likewise reports that nymphs pose a higher risk of disease transmission than adult ticks. **Should I stop worrying about ticks after summer?** No. CDC surveillance authors concluded that adult ticks seeking hosts in fall have a proportional role in human illness, and that prevention messages should not focus only on the spring and summer nymph season. The CDC lists fall alongside spring and summer as the period of greatest bite risk for blacklegged ticks. **What if I find a tick or feel sick after a bite?** Remove the tick as soon as possible rather than waiting for an appointment. The CDC says to see your doctor if you develop a rash or fever within several days to weeks after removing a tick, and to tell them when the bite happened and where you likely acquired the tick. Any medical decision belongs with your clinician. ### Related reading - [Ehrlichiosis: The Lone Star Tick's Signature Illness](https://longsleeve.com/blog/ehrlichiosis). The lone star tick's signature illness, in CDC numbers. - [When Is Mosquito Season?](https://longsleeve.com/blog/mosquito-season-by-region). Health-department months and temperature thresholds, region by region. - [Lyme Disease Prevention](https://longsleeve.com/blog/lyme-disease-prevention). Transmission, the attachment window, and the layers that lower risk. - [Tick Identification Guide](https://longsleeve.com/blog/tick-identification). Which tick bit you, and what it can carry. - [Our almanac of mosquitoes and ticks](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. CDC, Preventing Tick Bites. [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. CDC, Where Ticks Live. [https://www.cdc.gov/ticks/about/where-ticks-live.html](https://www.cdc.gov/ticks/about/where-ticks-live.html) 1. CDC, How Lyme Disease Spreads. [https://www.cdc.gov/lyme/causes/index.html](https://www.cdc.gov/lyme/causes/index.html) 1. CDC, Tick Lifecycles. [https://www.cdc.gov/ticks/about/tick-lifecycles.html](https://www.cdc.gov/ticks/about/tick-lifecycles.html) 1. CDC, Preventing Lyme Disease. [https://www.cdc.gov/lyme/prevention/index.html](https://www.cdc.gov/lyme/prevention/index.html) 1. CDC, What to Do After a Tick Bite. [https://www.cdc.gov/ticks/after-a-tick-bite/index.html](https://www.cdc.gov/ticks/after-a-tick-bite/index.html) 1. CDC NIOSH, Tickborne Diseases in Workers. [https://www.cdc.gov/niosh/outdoor-workers/about/tick-borne-diseases.html](https://www.cdc.gov/niosh/outdoor-workers/about/tick-borne-diseases.html) 1. Schwartz AM, Hinckley AF, Mead PS, Hook SA, Kugeler KJ. Surveillance for Lyme Disease, United States, 2008 to 2015. MMWR Surveillance Summaries, November 10, 2017;66(22):1-12. [https://www.cdc.gov/mmwr/volumes/66/ss/ss6622a1.htm](https://www.cdc.gov/mmwr/volumes/66/ss/ss6622a1.htm) 1. CDC Newsroom, CDC Data Show Weekly ER Visits for Tick Bites Higher than Usual, 2026. [https://www.cdc.gov/media/releases/2026/2026-cdc-data-show-weekly-er-visits-for-tick-bites-higher-than-usual.html](https://www.cdc.gov/media/releases/2026/2026-cdc-data-show-weekly-er-visits-for-tick-bites-higher-than-usual.html) 1. Telford SR III, Buchthal J, Elias P. Early Questing by Lone Star Tick Larvae, New York and Massachusetts, USA, 2018. Emerging Infectious Diseases, Volume 25, Number 8, August 2019. [https://wwwnc.cdc.gov/eid/article/25/8/18-1293_article](https://wwwnc.cdc.gov/eid/article/25/8/18-1293_article) 1. Duffy DC, Campbell SR. Ambient air temperature as a predictor of activity of adult *Ixodes scapularis* (Acari: Ixodidae). Journal of Medical Entomology, 1994;31(1):178-80. [https://pubmed.ncbi.nlm.nih.gov/8158624/](https://pubmed.ncbi.nlm.nih.gov/8158624/) 1. California Department of Public Health, Lyme Disease and Other Tick-Borne Diseases in California. [https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/2017LymeDiseaseinCABrochure.pdf](https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/2017LymeDiseaseinCABrochure.pdf) 1. California Department of Public Health, Seasonal Risk of Exposure to Infected Western Blacklegged (*Ixodes pacificus*) Ticks in California. [https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/SeasonalTickRiskGraphic.pdf](https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/SeasonalTickRiskGraphic.pdf) 1. CDC, Signs and Symptoms of Lyme Disease. [https://www.cdc.gov/lyme/signs-symptoms/index.html](https://www.cdc.gov/lyme/signs-symptoms/index.html) Last reviewed 2026-08-05 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Do Ultrasonic Mosquito Repellers Work? Cochrane Review, FTC Cases URL: https://longsleeve.com/blog/ultrasonic-repellers > What controlled trials, a Cochrane review, EPA device rules, and FTC enforcement history say about ultrasonic mosquito repellers and electronic mosquito repellents. Source: https://longsleeve.com/blog/ultrasonic-repellers By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 6, 2026 · Updated August 16, 2026 No. A Cochrane review of ten field studies found that electronic mosquito repellents have no effect on preventing mosquito bites, and laboratory and field trials since have agreed. The Federal Trade Commission has brought cases against marketers of these devices since the 1980s, and the EPA requires no premarket review of a device's effectiveness before sale. ### What are these devices supposed to do? Cochrane defines the category: electronic mosquito repellents "are designed to repel female mosquitoes by emitting high-pitched sounds almost inaudible to the human ear." The sales theory is that the sound scares off the biting females, and the stories sellers tell appear verbatim in FTC files. In its 2002 complaint against Lentek International, the [FTC](https://www.ftc.gov/news-events/news/press-releases/2002/08/ftc-alleges-electronic-mosquito-repellent-claims-are-false-sellers-also-lack-evidence-ultrasonic) described devices that "create sounds that mimic male mosquitoes and dragonflies, thereby supposedly frightening away the biting female mosquitoes." In 2004 it quoted a stroller clip whose ads said it "repels mosquitoes by electronically duplicating the wingbeat of the dragonfly." ### What did the Cochrane review find? Enayati, Hemingway, and Garner published the review in the Cochrane Database of Systematic Reviews in 2007. Ten field entomological studies met the inclusion criteria, and the result was unanimous: "All 10 studies found that there was no difference in the number of mosquitoes caught from the bare body parts of the human participants with or without an EMR." The conclusion: "Field entomological studies confirm that EMRs have no effect on preventing mosquito bites. Therefore there is no justification for marketing them to prevent malaria infection." Cochrane has since flagged the review as a "current question, no update intended: further research unlikely to change conclusions." ### What have individual studies found? - **Flight chamber, 1985.** Foster and Lutes tested five devices at fundamental frequencies of 20 to 70 kHz against four mosquito species. "For all species there was no significant difference between the numbers trapped when the devices were switched on or off, when all devices were tested simultaneously." Tests of individual devices against *Ae. aegypti* "also failed to show a repellent effect." (Journal of the American Mosquito Control Association) - **Reviews, 1998.** Coro and Suárez, surveying field tests run "in very different ecological conditions from Alaska to Equatorial Africa," concluded "these devices do not protect those who have them from the stings of mosquitoes" (Revista Cubana de Medicina Tropical). Fradin's clinician's guide that year: "ultrasonic devices, outdoor bug 'zappers,' and bat houses are not effective against mosquitoes" (Annals of Internal Medicine). - **Blinded household trial, Gabon, 2000.** Sylla, Lell, and Kremsner ran a paired, cross-over, blinded, placebo-controlled trial over eighteen nights in nine pairs of houses, catching 7,485 mosquitoes. "There was no significant difference in landing rate between the houses with ultrasound device and the houses with placebo for any species of mosquito." (Wiener Klinische Wochenschrift) - **Laboratory, Italy, 2024.** The Istituto Superiore di Sanità tested four ultrasonic repellers on female *Culex pipiens* and [Aedes albopictus](https://longsleeve.com/blog/asian-tiger-mosquito). Mean numbers drawn to the attractant with repellers on versus off were 2.8 versus 2.9 and 5.5 versus 6.1 respectively. "The repellence efficacy resulted not significant (P>0.05) in all the electronic ultrasound repellers tested." One study went past "no effect." Andrade and Cabrini counted *Aedes aegypti* bite attempts in a chamber over four three-minute cycles, alternately off and on. Across five frequencies from 9.6 kHz to 18.2 kHz, biting rates first rose significantly, by roughly 20 to 50 percent, then fell by 8.3 to 25.1 percent when switched off. Those are on/off changes inside one chamber, not a claim about your patio. But the title says it: "Electronic mosquito repellers induce increased biting rates in *Aedes aegypti* mosquitoes." (Journal of Vector Ecology, 2010) ### Do ultrasonic devices work on ticks? Same answer, thinner literature. Panthawong, Doggett, and Chareonviriyaphap tested nine ultrasonic devices against female *Ixodes holocyclus*, the Australian paralysis tick, in paired test and escape chambers. More ticks moved to the escape chamber in every test arena than in the controls, and three devices differed statistically from the control, but "the highest percent of ticks that escaped was only 19.5%," which the authors called "insufficient to offer adequate protection against tick bites." Their conclusion: "ultrasonic devices should not be employed in pest management." (Insects, 2021) A 2026 field trial on dogs in Mali tested an ultrasonic collar alongside three other collar types: "none of the tested collar-type products showed significant repellent effects." ### What has the FTC actually done about these claims? A consent agreement carries no admission that the law was broken, so what follows is allegations and settlements, not findings of fact. - **1985 to 1997.** "Between 1985 and 1997, the FTC brought law enforcement actions against six companies that allegedly made false and unsubstantiated claims about the effectiveness of ultrasonic devices in controlling rodent and insect infestations. Each of those cases was resolved by consent order." Per the same release, "previous FTC complaints alleged that ultrasound devices do not control insects." - **May 3, 2001.** FTC staff "sent warning letters to more than 60 manufacturers and retailers of ultrasonic pest-control devices, stating that efficacy claims about those products must be supported by scientific evidence." - **August 28, 2002.** An administrative complaint against Lentek International alleged the respondents "have falsely represented" that their MosquitoContro products "effectively repel mosquitoes from a user's body" and are "an effective alternative to the use of chemical pesticides" in preventing West Nile virus. Note the word: falsely, not unsubstantiated. Lentek settled February 4, 2003, and the final order issued that March. - **July 18, 2003.** Global Instruments settled charges over electromagnetic and ultrasonic products sold as Pest-A-Cator, PestVacator, and Riddex. - **June 21, 2004.** Prince Lionheart settled over the "Love Bug," a stroller clip whose ads claimed it "Helps protect your Baby from WEST NILE VIRUS!" The order bars false or unsubstantiated claims that any sonic or ultrasonic mosquito repellent repels mosquitoes, replaces chemical repellents, or protects people from contracting [West Nile virus](https://longsleeve.com/blog/west-nile-virus). - **May 24, 2016.** Viatek Consumer Products Group and its president Lou Lentine, the same principal named in the Lentek case, paid $300,000 over Mosquito Shield Bands. Those were mint-oil wristbands, not ultrasonic, but the FTC also charged them with violating the 2003 order. ### Why doesn't the EPA stop them? Because of a regulatory line most shoppers have never heard of. Under FIFRA a device is "any instrument or contrivance (other than a firearm) [that] is intended for trapping, destroying, repelling, or mitigating any pest," and the [EPA](https://www.epa.gov/pesticides/pesticide-devices-guide-consumers) names the category: "Products claiming to control pests via electromagnetic and/or electrical means (e.g., ultrasonic insect and rodent repellers, hand-held bug zappers, electric flea combs) are devices." **Short answer:** A Cochrane review of ten field studies found that electronic mosquito repellents have no effect on preventing mosquito bites, and later laboratory and field trials have not rescued the claim. EPA does not require pesticide devices to undergo premarket effectiveness review before sale, and the FTC has brought cases against marketers of ultrasonic repellers for decades. The EPA is not powerless. A device may be misbranded if its labeling carries "a false/misleading statement concerning the effectiveness of the device," and selling one is unlawful. Its February 2023 compliance advisory notes "substantial non-compliance with FIFRA in the device and pesticide marketplace." You can spot the difference on the shelf. Per the EPA, "a compliant EPA-regulated device will include an EPA Establishment Number on the label. It will not include an EPA Registration Number, which would only be found on registered pesticide products." The establishment number is no mark of quality. It marks where the device was produced, and per the EPA it "does NOT indicate that the product has been reviewed for safety or efficacy by EPA." On its repellent search page the agency adds that "EPA and the U.S. Government do not endorse any product or service." ### What does the CDC say to do instead? The [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) Yellow Book lists sound-emitting devices among the things that do not work: "Ingestion of vitamin B or garlic and wearing sound-emitting devices or repellent-impregnated wristbands are ineffective." For mosquito bites, the CDC says to use EPA-registered insect repellents with one of six active ingredients: DEET, picaridin (known as KBR 3023 and icaridin outside the United States), IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone. It adds: "Look for an EPA registration number (EPA Reg. No.) on the insect repellent product label. This registration number means the company provided EPA with technical information on the effectiveness of the product." It also recommends long-sleeved shirts and pants, permethrin-treated clothing and gear, window and door screens, and emptying water-holding containers weekly, which our guide to [standing water control](https://longsleeve.com/blog/standing-water-mosquito-control) covers. For ticks, see [prevention](https://longsleeve.com/blog/lyme-disease-prevention) and [removal](https://longsleeve.com/blog/tick-removal). ### What can you do if you already bought one? The EPA takes reports on labeling: "consumers can report a device that appears misbranded on EPA's website for all environmental violations." The FTC takes advertising complaints at ftc.gov or 1-877-FTC-HELP. ### Common questions **Do ultrasonic mosquito repellent phone apps work?** We found no study showing that they work. Andrade and Cabrini tested "three commercial devices and a computer program working on five different sound frequencies," and biting rates went up rather than down. Cochrane's ten field studies of the hardware these apps imitate found "no difference in the number of mosquitoes caught from the bare body parts of the human participants with or without an EMR." **Can an ultrasonic repeller make things worse?** In one chamber study it did. Andrade and Cabrini reported Aedes aegypti biting rates rising significantly, by roughly 20 to 50 percent, with the repellers on. That is a laboratory result, not a backyard measurement, but it is the opposite of the promised effect. **What about ultrasonic collars or plug-ins for ticks?** Testing has been unfavorable. Nine ultrasonic devices tested against female Ixodes holocyclus moved at most 19.5 percent of ticks into an escape chamber, which the authors called insufficient for protection against tick bites. A 2026 trial on dogs in Mali found none of the tested collar types, including an ultrasonic collar, showed significant repellent effects. Learn to identify the tick instead. A word on the testimonials. Bite counts move with where and when you count, which is why Cochrane only accepted field studies "which controlled for geographic site, time, and attractiveness of human participants," and why the trials above used blinding, placebo devices, and on/off cycles. Our guide to [why mosquitoes bite some people more](https://longsleeve.com/blog/why-mosquitoes-bite-some-people) covers individual differences. If a bite reaction worries you, or you develop fever or a rash after being bitten, talk to a clinician. Our [bite treatment guide](https://longsleeve.com/blog/mosquito-bite-treatment) covers ordinary cases. ### Where Longsleeve fits Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with [nine disclosed ingredients](https://longsleeve.com/ingredients). ### Related reading - [Natural Bug Repellents: What the Evidence Supports](https://longsleeve.com/blog/natural-repellents). Registered plant-derived actives, the exemption loophole, and the study data. - [Do Bug Zappers Work on Mosquitoes?](https://longsleeve.com/blog/bug-zappers). Two field studies counted the catch. Mosquitoes were 0.22 and 0.37 percent of it. - [Citronella Candles and Plant-Based Repellents](https://longsleeve.com/blog/citronella-and-plant-repellents). What the field trials actually measured. - [Standing Water and Mosquito Control](https://longsleeve.com/blog/standing-water-mosquito-control). What the CDC says about weekly container dumping. - [West Nile Virus in the United States](https://longsleeve.com/blog/west-nile-virus). Named in two FTC cases above. - [The field guide](https://longsleeve.com/facts). Species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. Enayati A, Hemingway J, Garner P. Electronic mosquito repellents for preventing mosquito bites and malaria infection. Cochrane Database of Systematic Reviews 2007, Issue 2. Art. No.: CD005434. [https://www.cochrane.org/evidence/CD005434_electronic-mosquito-repellents-preventing-mosquito-bites-and-malaria-infection](https://www.cochrane.org/evidence/CD005434_electronic-mosquito-repellents-preventing-mosquito-bites-and-malaria-infection) 1. Foster WA, Lutes KI. Tests of ultrasonic emissions on mosquito attraction to hosts in a flight chamber. Journal of the American Mosquito Control Association, 1985;1(2):199-202. [https://pubmed.ncbi.nlm.nih.gov/2906666/](https://pubmed.ncbi.nlm.nih.gov/2906666/) 1. Coro F, Suárez S. Electronic repellents against mosquitoes: the propaganda and the reality. Revista Cubana de Medicina Tropical, 1998;50(2):89-92. [https://pubmed.ncbi.nlm.nih.gov/10349423/](https://pubmed.ncbi.nlm.nih.gov/10349423/) 1. Fradin MS. Mosquitoes and mosquito repellents: a clinician's guide. Annals of Internal Medicine, 1998;128(11):931-40. [https://pubmed.ncbi.nlm.nih.gov/9634433/](https://pubmed.ncbi.nlm.nih.gov/9634433/) 1. Sylla el-H K, Lell B, Kremsner PG. A blinded, controlled trial of an ultrasound device as mosquito repellent. Wiener Klinische Wochenschrift, 2000;112(10):448-50. [https://pubmed.ncbi.nlm.nih.gov/10890136/](https://pubmed.ncbi.nlm.nih.gov/10890136/) 1. Andrade CFS, Cabrini I. Electronic mosquito repellers induce increased biting rates in Aedes aegypti mosquitoes (Diptera: Culicidae). Journal of Vector Ecology, 2010;35(1):75-8. [https://pubmed.ncbi.nlm.nih.gov/20618651/](https://pubmed.ncbi.nlm.nih.gov/20618651/) 1. Panthawong A, Doggett SL, Chareonviriyaphap T. The Efficacy of Ultrasonic Pest Repellent Devices against the Australian Paralysis Tick, Ixodes holocyclus (Acari: Ixodidae). Insects, 2021;12(5):400. [https://pubmed.ncbi.nlm.nih.gov/33946185/](https://pubmed.ncbi.nlm.nih.gov/33946185/) 1. Toma L, Lo Castro F, Severini F, et al. Evaluation of four common electronic mosquito repellers on Aedes albopictus and Culex pipiens. Annali dell'Istituto Superiore di Sanità, 2024;60(4):258-263. [https://pubmed.ncbi.nlm.nih.gov/39699979/](https://pubmed.ncbi.nlm.nih.gov/39699979/) 1. Junnila A, Revay EE, Traore M, et al. Efficacy of repellents against fleas and ticks: a field trial on free roaming dogs in Mali, West Africa. Frontiers in Insect Science, 2026;6:1811490. [https://pubmed.ncbi.nlm.nih.gov/42518720/](https://pubmed.ncbi.nlm.nih.gov/42518720/) 1. FTC, FTC Warns Manufacturers and Retailers of Ultrasonic Pest-control Devices (May 3, 2001). [https://www.ftc.gov/news-events/news/press-releases/2001/05/ftc-warns-manufacturers-retailers-ultrasonic-pest-control-devices](https://www.ftc.gov/news-events/news/press-releases/2001/05/ftc-warns-manufacturers-retailers-ultrasonic-pest-control-devices) 1. FTC, FTC Alleges Electronic Mosquito Repellent Claims Are False (August 28, 2002). [https://www.ftc.gov/news-events/news/press-releases/2002/08/ftc-alleges-electronic-mosquito-repellent-claims-are-false-sellers-also-lack-evidence-ultrasonic](https://www.ftc.gov/news-events/news/press-releases/2002/08/ftc-alleges-electronic-mosquito-repellent-claims-are-false-sellers-also-lack-evidence-ultrasonic) 1. FTC, Seller of Various Pest-Control Devices and Air Cleaning Products Settles FTC Charges (February 4, 2003). [https://www.ftc.gov/news-events/news/press-releases/2003/02/seller-various-pest-control-devices-air-cleaning-products-settles-ftc-charges](https://www.ftc.gov/news-events/news/press-releases/2003/02/seller-various-pest-control-devices-air-cleaning-products-settles-ftc-charges) 1. FTC, Marketer of Pest Control Devices Required to Provide Support for Claims (July 18, 2003). [https://www.ftc.gov/news-events/news/press-releases/2003/07/marketer-pest-control-devices-required-provide-support-claims](https://www.ftc.gov/news-events/news/press-releases/2003/07/marketer-pest-control-devices-required-provide-support-claims) 1. FTC, The "Love Bug" Does Not Repel Mosquitos: FTC Challenges Claims for Ultrasonic Device (June 21, 2004). [https://www.ftc.gov/news-events/news/press-releases/2004/06/love-bug-does-not-repel-mosquitos-ftc-challenges-claims-ultrasonic-device](https://www.ftc.gov/news-events/news/press-releases/2004/06/love-bug-does-not-repel-mosquitos-ftc-challenges-claims-ultrasonic-device) 1. FTC, Marketers of "Mosquito Shield Bands" to Pay $300,000 (May 24, 2016). [https://www.ftc.gov/news-events/news/press-releases/2016/05/marketers-mosquito-shield-bands-pay-300000-barred-making-misleading-pest-control-claims-under](https://www.ftc.gov/news-events/news/press-releases/2016/05/marketers-mosquito-shield-bands-pay-300000-barred-making-misleading-pest-control-claims-under) 1. EPA, Pesticide Devices: A Guide for Consumers. [https://www.epa.gov/pesticides/pesticide-devices-guide-consumers](https://www.epa.gov/pesticides/pesticide-devices-guide-consumers) 1. EPA, Compliance Advisory: What You Need to Know About Producing, Distributing or Selling Pesticide Devices (February 2023, EPA Document 305F22003). [https://www.epa.gov/system/files/documents/2023-03/pesticidedevicecomplianceadvisory.pdf](https://www.epa.gov/system/files/documents/2023-03/pesticidedevicecomplianceadvisory.pdf) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) Last reviewed 2026-08-06 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. ## Vector-Borne Disease in the U.S.: CDC Counts, Ticks, Mosquitoes URL: https://longsleeve.com/blog/vector-borne-disease-numbers > CDC case-count data for U.S. vector-borne disease from 2001 to 2023, including ticks, mosquitoes, Lyme disease, reporting limits, and regional concentration. Source: https://longsleeve.com/blog/vector-borne-disease-numbers By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 16, 2026 The CDC counts more than 1 million vector-borne disease cases reported in the United States between 2001 and 2023, and says annual reports more than doubled over that period. Ticks drive most of the volume, Lyme disease most of that. The case counts here are reported counts, and reported counts run well below true infections. ### How many vector-borne disease cases get reported in the US each year? The [CDC](https://www.cdc.gov/vector-borne-diseases/about/index.html)'s summary line: "Cases of VBDs have increased significantly since 2004, with more than 1 million cases reported between 2001 and 2023 in the United States. Annual reported VBD cases more than doubled during this period." States, territories, and freely associated states "voluntarily report cases of 17 VBDs to CDC." **Short answer:** CDC data count more than 1 million vector-borne disease cases reported in the United States between 2001 and 2023, and annual reports more than doubled over that period. Ticks drive most of the reported volume, and Lyme disease drives most of the tick total. The counts are reported cases, not true infections, so they understate the real burden. The CDC describes the two halves differently. "Epidemics characterize the mosquitoborne viruses," while "the increasing reports of tickborne disease, which occurs almost exclusively in the continental United States, has been gradual." Annual reports of tickborne bacterial and protozoan diseases went "from >22,000 in 2004 to >48,000 in 2016." A later CDC analysis: "Overall, U.S. tickborne disease cases have increased 25%, from 40,795 reported in 2011 to 50,856 in 2019." ### Which single disease accounts for the most cases? Lyme, by a wide margin. Across 2004 to 2016, "Lyme disease accounted for 82% of all tickborne disease reports," with 402,502 cases in the CDC table. Lyme has been nationally notifiable since 1991. Then the counting rules changed. Effective January 1, 2022, the Council of State and Territorial Epidemiologists and the [CDC](https://www.cdc.gov/mmwr/volumes/73/wr/mm7306a1.htm) revised the national surveillance case definition so that high-incidence jurisdictions could report cases "based on laboratory evidence alone, without the need to collect additional clinical information." *MMWR* reported 62,551 Lyme cases for 2022, which the authors put at 1.7 times the annual average of 37,118 cases reported during 2017 to 2019. That jump is a measurement artifact, and the CDC says so: the increase "likely reflects changes in surveillance methods rather than change in disease risk," and that the changes "preclude detailed comparison with historical data." Geography stays concentrated: "Approximately 90% of all cases are reported from 15 high-incidence jurisdictions in the Northeast, mid-Atlantic, and upper-Midwest regions." For 2023, "Over 89,000 cases of Lyme disease were reported to CDC by state health departments and the District of Columbia." See our [Lyme prevention guide](https://longsleeve.com/blog/lyme-disease-prevention). ### What do the other tickborne numbers look like? Smaller counts. Across 2004 to 2016, the CDC table shows anaplasmosis and ehrlichiosis combined rising from 875 reports in 2004 to 5,750 in 2016, and spotted fever rickettsiosis from 1,713 to 4,269. Babesiosis, notifiable only since 2011, ran 1,128 in 2011 to 1,910 in 2016. A dedicated babesiosis analysis found "a total of 16,456 cases of babesiosis were reported to CDC by 37 states" during 2011 to 2019. State rate changes were large: Vermont "reported two cases in 2011 (incidence=0.3 per 100,000 population) and 34 cases in 2019 (5.4), representing a 1,602% increase in incidence," and Maine went from "nine cases in 2011 (0.7) and 138 cases in 2019 (10.3), a 1,422% rate increase." Geography splits by pathogen. Per the [CDC](https://www.cdc.gov/ticks/communication-resources/press-kit.html), "More than 75 percent of spotted fever rickettsiosis cases (including RMSF) occur in seven states: Arkansas, Missouri, North Carolina, Oklahoma, Virginia, Alabama, and Tennessee," while reported cases of Lyme, anaplasmosis, babesiosis, and Powassan virus disease are "concentrated in the Northeast, mid-Atlantic, and upper Midwest, with pockets of risk along the Pacific coast." Start with [tick identification](https://longsleeve.com/blog/tick-identification). [Alpha-gal syndrome](https://longsleeve.com/blog/alpha-gal-syndrome) sits outside routine surveillance. An *MMWR* study of commercial lab testing counted "a total of 110,229 suspected cases" during 2010 to 2022, and noted that "in the absence of a national surveillance system, the prevalence of this condition is largely unknown." ### What are the West Nile virus numbers? The [CDC](https://www.cdc.gov/west-nile-virus/about/index.html) calls West Nile "the leading cause of mosquito-borne disease in the contiguous United States." Its surveillance data page, with 2025 data preliminary and current as of June 2, 2026, puts cumulative human disease cases at 63,155 and deaths at 3,315 for 1999 through 2025. The year-to-year swing is the story. The 2024 count of 1,808 sat "below the 10-year median of 2,162 cases," with an interquartile interval of 1,132 to 2,628 around that median. Single states move the national total: Texas reported 456 cases in 2024, "more than double the number reported in Texas in 2023 (163)." The CDC's round number is "about 2,000 people in the United States are diagnosed with West Nile" each year, "but this number is an underestimate." For 2024, [CDC](https://www.cdc.gov/mmwr/volumes/75/wr/mm7529a1.htm) surveillance authors reported that 48 states and DC "reported 1,955 arboviral disease cases, including 189 (10%) deaths," with West Nile accounting for 1,808, or 92 percent. That year, "173 (9.6%) patients with reported WNV disease died, 169 (98%) of whom had neuroinvasive disease (case-fatality rate [CFR] = 13% among patients with neuroinvasive disease)." The 13 percent is a rate among neuroinvasive patients, not among everyone infected. More in our [West Nile explainer](https://longsleeve.com/blog/west-nile-virus). ### How big is dengue in the US, and where does it come from? Mostly from a plane. Per the [CDC](https://www.cdc.gov/dengue/data-research/facts-stats/index.html), "Most dengue cases reported in the 49 continental US states occur in travelers infected elsewhere," while dengue "is common in the U.S. territories of American Samoa, Puerto Rico, and the U.S. Virgin Islands, and the freely associated states." 2024 broke the record. Per *MMWR*, ArboNET received an average of 828 dengue cases a year from the 50 states and DC during 2010 through 2023, in a range of 202 to 2,055. In 2024 "a record 3,798 dengue cases were reported, representing a 359% increase above the" 2010 to 2023 average. Of those, "97.2% were associated with travel outside the reporting jurisdiction during the 2 weeks preceding symptom onset; the remaining 2.8% were locally acquired." The locally acquired cases came from Florida (85), California (18), and Texas (two). Severity, same report: "Among all patients, 36.1% required hospitalization, 2.8% of cases were severe, and six (0.2%) patients died." The authors flag their counts as "preliminary and might not reflect final counts for 2024." See [dengue and travel](https://longsleeve.com/blog/dengue-travel). ### What does surveillance data not capture? The CDC's *MMWR* analysis is blunt: "The reported data substantially underestimate disease occurrence. NNDSS relies on a person seeking care, a clinician requesting appropriate tests, and providers or laboratories reporting to public health authorities." Three specific gaps, each with a number attached: - **Lyme.** The CDC says "approximately 476,000 people may be diagnosed and treated for Lyme disease each year in the United States," adding that this "likely includes patients who are treated based on clinical suspicion but do not actually have Lyme disease." Even after the 2022 definition change, reported totals still do "not approach" that estimate. - **West Nile.** CDC authors cite historical ratios of 30 to 70 nonneuroinvasive disease cases for every reported case of West Nile neuroinvasive disease. Applied to 2024, that implies 40,410 to 94,290 nonneuroinvasive cases nationally, against 461 actually reported, which they put at 0.5 to 1 percent of the estimated total. - **Dengue.** "Reported case counts are an underestimate of the true number of infections, because many persons with dengue have mild symptoms or might not seek health care services." Two more caveats. For West Nile, the CDC notes surveillance data "are reported by county of residence, not the location (county or state) of exposure," and Lyme cases are likewise reported from the infected person's county of residence, so a case counted in one place may have been acquired elsewhere. And during the COVID-19 pandemic, fewer tickborne cases were reported, which the CDC attributes to "the effects of the COVID-19 pandemic on tickborne disease surveillance rather than an actual decrease in the numbers of tickborne diseases." ### What does the CDC recommend, given these numbers? For ticks, the [CDC](https://www.cdc.gov/ticks/prevention/index.html)'s prevention page says to "Use Environmental Protection Agency (EPA)-registered insect repellents containing DEET, picaridin, IR3535, Oil of Lemon Eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone," and to "Treat clothing and gear with products containing 0.5% permethrin." It also says to look for an EPA registration number on the label. The EPA, for its part, states plainly: "EPA and the U.S. Government do not endorse any product or service." For arboviral disease, CDC surveillance authors write that prevention and control "rely on use of personal protective measures (e.g., using insect repellent registered by the Environmental Protection Agency and wearing protective clothing)," on vector-control activities "both at household and community levels," and on "WNV blood and organ donor screening." See [permethrin-treated clothing](https://longsleeve.com/blog/permethrin-clothing) and [standing water control](https://longsleeve.com/blog/standing-water-mosquito-control). ### When during the year do the numbers peak? Tightly, and in summer. Across 1999 to 2025, West Nile cases by month of illness onset run 9,967 in July, 28,697 in August, and 17,979 in September. In 2024, 82 percent of all arboviral disease patients had illness onset during July through September, and dengue cases peaked over the same three months, accounting for 41.6 percent of the annual total. Lyme onset peaked during calendar week 26 in both the 2017 to 2019 period and 2022. Powassan runs differently: 28 of 60 cases in 2024 had onset during April through June, which fits a tick active earlier and later than mosquitoes. More in [when tick season actually starts](https://longsleeve.com/blog/tick-season-when). ### Where Longsleeve fits Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with [nine disclosed ingredients](https://longsleeve.com/ingredients). ### Common questions **Why did Lyme cases jump so much in 2022?** The surveillance case definition changed. From January 1, 2022, high-incidence jurisdictions could report cases on laboratory evidence alone. The CDC says the increase "likely reflects changes in surveillance methods rather than change in disease risk," and that the changes "preclude detailed comparison with historical data." **How far off are reported case counts?** It depends on the disease. The CDC estimates "only 1 in 10 West Nile virus cases are reported, and the number of treated Lyme disease cases is possibly 10 times higher than the number reported to CDC." For West Nile in 2024, the CDC estimated 40,410 to 94,290 nonneuroinvasive cases against 461 reported, an even wider gap than the 1 in 10 figure. **Is dengue spreading inside the United States?** Mostly it arrives with travelers. In 2024, 97.2 percent of the record 3,798 reported cases were travel associated and 2.8 percent were locally acquired, from Florida, California, and Texas. The CDC notes that limited local spread has been reported in Florida, Hawaii, Texas, Arizona, and California. **What should I do if I think I have one of these illnesses?** See a healthcare provider. The CDC says providers diagnose vector-borne infections based on signs and symptoms, history of possible exposure to mosquitoes, ticks, or fleas, and laboratory testing. Any decision about testing or treatment belongs with your clinician. ### Related reading - [How to remove a tick](https://longsleeve.com/blog/tick-removal). What the CDC says to do, step by step. - [The Asian tiger mosquito](https://longsleeve.com/blog/asian-tiger-mosquito). A sourced profile of the species. - [Our species field guide](https://longsleeve.com/facts). Species, ranges, and the diseases they carry, sourced. More Longsleeve in your Google feed: ### Sources 1. CDC, About Vector-Borne Diseases. [https://www.cdc.gov/vector-borne-diseases/about/index.html](https://www.cdc.gov/vector-borne-diseases/about/index.html) 1. CDC MMWR: Vital Signs: Trends in Reported Vectorborne Disease Cases, United States and Territories, 2004 to 2016. [https://www.cdc.gov/mmwr/volumes/67/wr/mm6717e1.htm](https://www.cdc.gov/mmwr/volumes/67/wr/mm6717e1.htm) 1. CDC, Lyme Disease Surveillance and Data. [https://www.cdc.gov/lyme/data-research/facts-stats/index.html](https://www.cdc.gov/lyme/data-research/facts-stats/index.html) 1. CDC, Lyme Disease Case Map. [https://www.cdc.gov/lyme/data-research/facts-stats/lyme-disease-case-map.html](https://www.cdc.gov/lyme/data-research/facts-stats/lyme-disease-case-map.html) 1. CDC MMWR: Surveillance for Lyme Disease After Implementation of a Revised Case Definition, United States, 2022. [https://www.cdc.gov/mmwr/volumes/73/wr/mm7306a1.htm](https://www.cdc.gov/mmwr/volumes/73/wr/mm7306a1.htm) 1. CDC MMWR: Trends in Reported Babesiosis Cases, United States, 2011 to 2019. [https://www.cdc.gov/mmwr/volumes/72/wr/mm7211a1.htm](https://www.cdc.gov/mmwr/volumes/72/wr/mm7211a1.htm) 1. CDC MMWR: Geographic Distribution of Suspected Alpha-gal Syndrome Cases, United States, January 2017 to December 2022. [https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a2.htm](https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a2.htm) 1. CDC MMWR: West Nile Virus and Other Nationally Notifiable Arboviral Diseases, United States, 2024. [https://www.cdc.gov/mmwr/volumes/75/wr/mm7529a1.htm](https://www.cdc.gov/mmwr/volumes/75/wr/mm7529a1.htm) 1. CDC MMWR: Increase in Travel-Associated and Locally Acquired Dengue Cases, United States, 2024. [https://www.cdc.gov/mmwr/volumes/75/wr/mm7518a1.htm](https://www.cdc.gov/mmwr/volumes/75/wr/mm7518a1.htm) 1. CDC, West Nile Virus Historic Data (1999-2025). [https://www.cdc.gov/west-nile-virus/data-maps/historic-data.html](https://www.cdc.gov/west-nile-virus/data-maps/historic-data.html) 1. CDC, About West Nile. [https://www.cdc.gov/west-nile-virus/about/index.html](https://www.cdc.gov/west-nile-virus/about/index.html) 1. CDC, Data and Statistics on Dengue in the United States. [https://www.cdc.gov/dengue/data-research/facts-stats/index.html](https://www.cdc.gov/dengue/data-research/facts-stats/index.html) 1. CDC, Press Kit: Understanding Lyme and Other Tickborne Diseases. [https://www.cdc.gov/ticks/communication-resources/press-kit.html](https://www.cdc.gov/ticks/communication-resources/press-kit.html) 1. CDC, Preventing Tick Bites. [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) Last reviewed 2026-08-16 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Should You Wash Off Bug Spray? Before Bed, After a Hike, on Kids URL: https://longsleeve.com/blog/wash-off-bug-spray > Yes. Wash treated skin and clothes with soap and water once you are indoors; it is printed on the label. Skipping it, sleeping in it, kids, and the smell. Source: https://longsleeve.com/blog/wash-off-bug-spray By [Andrew Rothaus](https://longsleeve.com/about), Founder · September 9, 2026 **Short answer:** Yes. Once you are back indoors, wash treated skin with soap and water and [wash treated clothing before you wear it again](https://longsleeve.com/blog/bug-spray-on-clothes). That instruction is printed on DEET product labels and repeated by EPA and the American Academy of Pediatrics; the CDC's Yellow Book carries the skin half. No source addresses sleeping in it; the label's cutoff is coming indoors. ### What does the repellent label actually tell you to do? Wash it off when you come inside, and wash the clothes before you wear them again. The instruction is on the bottle. EPA's page on DEET says all DEET product labels include a set of directions to help reduce the chance of DEET irritating your skin or eyes, and two of them are these: after returning indoors, wash treated skin with soap and water, and wash treated clothing before wearing it again. The label carries legal weight. The same [EPA](https://www.epa.gov/insect-repellents/deet) page states that FIFRA requires that pesticides be used according to the approved label, and tells users to always follow the recommendations appearing on the product label. The wash line is one of those label directions. [EPA](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively)'s general guidance on repellents says it in one line: after returning indoors, wash treated skin and clothes with soap and water. The same page says to apply and reapply a repellent according to the label instructions, not to overuse the products, and to apply the amount of repellent the label indicates. ### Should you wash off bug spray before bed? Yes. Bedtime is the last practical moment to do what the label already told you to do at the door. Say it plainly: no agency we cite addresses sleeping in repellent, in either direction. EPA, the DEET label, the CDC's Yellow Book, the American Academy of Pediatrics and the Massachusetts Department of Public Health all say the same thing: wash when you come indoors. Still wearing it at bedtime means you skipped a step, and bed is where you catch it. What the sources document is irritation after extended contact. The National Pesticide Information Center says people who have left DEET products on their skin for extended periods of time have experienced irritation, redness, a rash and swelling, and the DEET label itself warns that use of the product may cause skin reactions in rare cases. NPIC's report describes DEET left on skin for extended periods and does not address sleeping. The instruction that does exist is the one on the label: wash when you come indoors. ### What happens if you don't wash off DEET? No source we can cite defines what a single skipped wash does. The label says use of the product may cause skin reactions in rare cases. The National Pesticide Information Center reports that people who left DEET products on their skin for extended periods of time have experienced irritation, redness, a rash and swelling. The [CDC](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html)'s Yellow Book says severe reactions to insect repellents are rare, and that a traveler with a rash, itching or swelling from a repellent should wash it off with mild soap and water and stop using it. For picaridin, NPIC says some people have had skin irritation from products containing it, although this is very uncommon. The reassuring half is in NPIC's DEET technical fact sheet: researchers determined that 5.6 percent of a dose of technical grade DEET was absorbed through the skin, DEET did not accumulate in superficial layers of human skin, and most of the absorbed dose was eliminated within 12 hours of application with nearly all of it gone within 24 hours. [NPIC](http://npic.orst.edu/factsheets/DEETgen.html)'s general fact sheet compresses that to one line: nearly all of the DEET taken in through the skin is eliminated by the body within 24 hours of applying it. So the documented downside lives at the skin, and every source we cite tells you to wash it off. The longer record is in [our review of the DEET safety evidence](https://longsleeve.com/blog/deet-safety-evidence). ### Does bug spray absorb into your skin? Some does, and the body clears nearly all of that fraction within a day. The figures come from the National Pesticide Information Center's technical fact sheets, which we cite in place of the underlying studies. For DEET, the sheet reports 5.6 percent of a dose of technical grade DEET absorbed through the skin, and 8.4 percent when the DEET was in an ethanol solution. Most of the absorbed dose was eliminated within 12 hours and nearly all within 24, and essentially all of it, less than 10 percent of what was applied, was excreted in the urine. For picaridin, [NPIC](http://npic.orst.edu/factsheets/archive/Picaridintech.html)'s technical fact sheet reports that less than 6 percent of the applied doses were absorbed after an 8-hour exposure. Treat that as an upper bound from an 8-hour exposure. On the way out, NPIC says excretion of radio-labeled picaridin applied to the arms of human volunteers was nearly complete in 24 hours. The on-skin side of the question is in [how long picaridin lasts](https://longsleeve.com/blog/how-long-does-picaridin-last). ### How do you wash bug spray off skin? Soap and water. Every source that addresses removal says to wash, the ones that name a cleanser all name soap and water, and none of them names a special cleanser: EPA for treated skin and clothes, the DEET label for treated skin, the CDC's Yellow Book (mild soap and water) for a rash or other reaction. The Massachusetts Department of Public Health says to wash your skin and the clothes that had repellent on them when you come inside. Hands first. NPIC notes it may be possible to swallow DEET if the hands are not washed after using DEET on skin. Then the laundry: DEET labels say wash treated clothing before wearing it again, and the American Academy of Pediatrics says the same for children's clothes. After a hike in tick country the shower does two jobs. The [CDC](https://wwwnc.cdc.gov/travel/page/avoid-bug-bites) says showering within two hours of coming indoors has been shown to reduce your risk of getting tick-borne diseases, that showering may help wash off unattached ticks, and that it is a good opportunity to do a tick check. The back-at-camp routine is in [insect repellent for hiking](https://longsleeve.com/blog/insect-repellent-for-hiking), and the tick check in [Lyme disease prevention](https://longsleeve.com/blog/lyme-disease-prevention). ### How long should you leave bug spray on? For as long as you are outdoors and need it, then off when you come in. No source we cite publishes a maximum number of hours a repellent may stay on skin. The instruction that exists is the label's: after returning indoors, wash treated skin with soap and water. What the sources do say is that more is not better. EPA says to apply and reapply according to the label instructions and not to overuse the products. The CDC's Yellow Book says to use just enough repellent to cover exposed skin or clothing, and that heavy application and saturation are generally unnecessary for effectiveness. ### How do you wash repellent off kids? Soap and water or a bath, as soon as they come in. EPA's note for children says that after returning indoors, wash your child's treated skin and clothes with soap and water, or bathe. The CDC's Yellow Book says to wash children's treated skin and clothing with soap and water after returning indoors, or give the child a bath. The [American Academy of Pediatrics](https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx) says to wash your children's skin with soap and water to remove any repellent when they return indoors, and to wash their clothing before they wear it again. If a child reacts, the American Academy of Pediatrics says to stop using the product and wash the child's skin with soap and water. Ages, application and the rest of the routine are in [mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). For infants, the sources lead with clothing and netting. The CDC says travelers can protect infants from insect bites by dressing them in clothing that covers their arms and legs, by covering strollers and baby carriers with mosquito netting, and by using appropriate insect repellent. The Massachusetts Department of Public Health says DEET products should not be used on infants under 2 months of age, and to use mosquito netting on baby carriages or playpens when your infant is outside. ### Can you sleep with bug spray on? No source we cite addresses sleeping in repellent in either direction. What the label does say is to wash treated skin with soap and water after returning indoors, and EPA's general guidance says the same for skin and clothes, so the answer is built from the instruction that exists: come in, wash it off. What the agencies name for the night is a barrier. The CDC says to sleep under a mosquito net if you are outside or when screened rooms are not available, and notes that mosquitoes can live indoors and bite during the day and night. The [World Health Organization](https://www.who.int/news-room/fact-sheets/detail/malaria), writing about malaria, says to use mosquito nets when sleeping in places where malaria is present. For infants the tool is netting: over strollers and baby carriers per the CDC, on baby carriages or playpens per the Massachusetts Department of Public Health. We will not tell you that repellent works indoors or that it does not, because none of our sources says either. ### How long does bug spray smell take to go away? No published figure exists, so we will not give you one. The National Pesticide Information Center describes DEET as a colorless liquid with a faint odor, and technical grade picaridin as a colorless liquid with little odor. NPIC describes the actives themselves as barely scented, so those two sheets do not account for a repellent that fills the tent. We have no sourced trick for getting a scent off faster and will not invent one. Removal is the same step as everything else here: EPA says wash treated skin and clothes with soap and water after returning indoors. ### Common questions **Should you wash off bug spray before bed?** Yes. EPA says to wash treated skin and clothes with soap and water after returning indoors, DEET product labels carry the same direction for treated skin, and the American Academy of Pediatrics says to wash children's skin with soap and water to remove any repellent when they return indoors. No source addresses sleeping in it; the instruction you have is the wash-when-you-come-in line, and bed is the last chance to follow it. **What happens if you don't wash off DEET?** No source defines the result of one skipped wash. What is documented is at the skin: DEET labels say use may cause skin reactions in rare cases, and the National Pesticide Information Center says people who left DEET products on their skin for extended periods have experienced irritation, redness, a rash and swelling. NPIC 's technical fact sheet reports that most of the absorbed dose was eliminated within 12 hours and nearly all of it within 24 hours. **Can babies wear bug spray overnight?** No source addresses it, and the infant guidance points elsewhere. The Massachusetts Department of Public Health says DEET products should not be used on infants under 2 months of age, and says to use mosquito netting on baby carriages or playpens when your infant is outside. The CDC lists clothing that covers arms and legs and netting over strollers and baby carriers, and its overnight tool is a mosquito net where screened rooms are not available. **Does washing remove the bug spray smell?** Washing is the only removal step any source gives: EPA says to wash treated skin and clothes with soap and water after returning indoors. As for the smell itself, the National Pesticide Information Center describes DEET as a colorless liquid with a faint odor and technical grade picaridin as a colorless liquid with little odor, so those two sheets do not account for a strong scent. None of this is medical advice. If a rash, itching or swelling follows a repellent, wash it off with soap and water, stop using it, and talk to a clinician. ### About Longsleeve Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. Its label claims include [fragrance free](https://longsleeve.com/ingredients) and no chemical scent or odor, and its label directions say to wash thoroughly with soap and water after handling, to stop and see a doctor if irritation or rash occurs, and to use no more than two applications a day. ### Related reading - [Mosquito repellent for kids](https://longsleeve.com/blog/mosquito-repellent-for-kids). Ages, application, and the indoor tools for infants. - [Insect repellent for hiking](https://longsleeve.com/blog/insect-repellent-for-hiking). The back-at-camp routine. - [Lyme disease prevention](https://longsleeve.com/blog/lyme-disease-prevention). Tick checks and the two-hour shower. - [The DEET safety evidence](https://longsleeve.com/blog/deet-safety-evidence). The full safety record. - [How long does picaridin last?](https://longsleeve.com/blog/how-long-does-picaridin-last). How long picaridin stays on skin and in the body. - [Does Bug Spray Expire? What EPA's Label Rules Actually Require](https://longsleeve.com/blog/does-bug-spray-expire). What EPA's label rules actually require, plus heat, freezing and disposal. - [Bug Spray and Sunscreen: Which Goes On First, How Long to Wait, and Why Not a Combo](https://longsleeve.com/blog/bug-spray-and-sunscreen). Sunscreen first, then repellent, and why not a combo. - [Picaridin Lotion vs Spray: Which Form Actually Works Better?](https://longsleeve.com/blog/picaridin-lotion-vs-spray). What actually decides how long you are protected. - [Can You Put Bug Spray on Your Face? Yes, Hands First, and Here Is Why the Label Says So](https://longsleeve.com/blog/bug-spray-on-face). Hands first, and what to do if it gets in your eyes. ### Sources 1. EPA, DEET. [https://www.epa.gov/insect-repellents/deet](https://www.epa.gov/insect-repellents/deet) 1. EPA, Using Insect Repellents Safely and Effectively. [https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) 1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods. [https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html) 1. American Academy of Pediatrics, HealthyChildren.org, Insect Repellents. [https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx](https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Insect-Repellents.aspx) 1. Massachusetts Department of Public Health, Mosquito Repellents. [https://www.mass.gov/info-details/mosquito-repellents](https://www.mass.gov/info-details/mosquito-repellents) 1. NPIC, DEET General Fact Sheet. [http://npic.orst.edu/factsheets/DEETgen.html](http://npic.orst.edu/factsheets/DEETgen.html) 1. NPIC, Picaridin General Fact Sheet. [http://npic.orst.edu/factsheets/PicaridinGen.html](http://npic.orst.edu/factsheets/PicaridinGen.html) 1. NPIC, DEET Technical Fact Sheet. [http://npic.orst.edu/factsheets/archive/DEETtech.html](http://npic.orst.edu/factsheets/archive/DEETtech.html) 1. NPIC, Picaridin Technical Fact Sheet. [http://npic.orst.edu/factsheets/archive/Picaridintech.html](http://npic.orst.edu/factsheets/archive/Picaridintech.html) 1. CDC Travelers' Health, Avoid Bug Bites. [https://wwwnc.cdc.gov/travel/page/avoid-bug-bites](https://wwwnc.cdc.gov/travel/page/avoid-bug-bites) 1. WHO, Malaria fact sheet. [https://www.who.int/news-room/fact-sheets/detail/malaria](https://www.who.int/news-room/fact-sheets/detail/malaria) Last reviewed 2026-09-09 · every claim on this page is sourced above ## West Nile Virus in NYC 2026: Case Counts, Spray Dates, Prevention URL: https://longsleeve.com/blog/west-nile-virus-nyc > NYC Health data read October 2, 2026: 29 West Nile neuroinvasive cases and 1,769 positive mosquito pools. Borough numbers, spray status, prevention. Source: https://longsleeve.com/blog/west-nile-virus-nyc By [Andrew Rothaus](https://longsleeve.com/about), Founder · September 6, 2026 · Updated October 2, 2026 **Short answer:** Yes. NYC Health's Summary Data page, read on October 2, 2026, lists 1,769 positive mosquito pools, 29 cases of West Nile neuroinvasive disease and 6 cases of West Nile fever for the year. No spraying is scheduled right now: the city's Mosquito Control page says there are no events currently scheduled, and its most recent spraying was scheduled for September 21 and 23. ### Is West Nile virus in NYC right now? Yes. [NYC Health](https://www.nyc.gov/site/doh/health/health-topics/west-nile-virus-reports.page)'s Summary Data page, read on October 2, 2026, lists 1,769 West Nile positive mosquito pools for 2026, 29 New York City residents reported with West Nile neuroinvasive disease, and 6 reported with West Nile fever. When we first read the page on September 6, those figures were 1,568, 9 and 3. The page prints no "as of" date, so treat these as the count on the day we read them, and check the page for a newer number before you rely on it. The two human rows are not the same illness. NYC Health counts neuroinvasive disease as cases of West Nile encephalitis, meningitis or acute flaccid paralysis, which it describes as severe muscle weakness associated with the infection. West Nile fever is the milder category: infection with mild to moderate illness and no evidence of central nervous system involvement. People whose donated blood tested positive are tracked separately and are not included in the human case count, because, as the Health Department explains, they do not meet the national case definition. The state publishes its own count, which confuses people reading two sources at once. In its statewide report dated September 28, 2026, covering January 10 through September 26, the New York State Department of Health reported 34 human West Nile cases in New York City and 20 outside it. The same report counted 1,757 positive mosquito pools from New York City counties and 393 from the rest of the state. The state says its New York City data are derived from the city health department's website, and notes that the city reports its human cases directly to the CDC. Read the city's own page for the city's count, and expect the two files to disagree. The [CDC](https://www.cdc.gov/west-nile-virus/data-maps/current-year-data.html)'s national surveillance page for 2026 was last updated September 29, and the CDC says that state and local health departments may have more up-to-date information than what it presents. ### Which boroughs have the most West Nile positive mosquitoes? Queens, then Staten Island. Queens has 668 positive mosquito pools and Staten Island 441. The human cases fall differently: Brooklyn has the most reported neuroinvasive cases, 10. Every figure below is as posted on NYC Health's Summary Data page when we read it on October 2, 2026. | Borough | Positive mosquito pools | Neuroinvasive cases | West Nile fever cases | |---|---|---|---| | Bronx | 221 | 3 | 0 | | Brooklyn | 338 | 10 | 2 | | Manhattan | 101 | 3 | 0 | | Queens | 668 | 7 | 2 | | Staten Island | 441 | 6 | 2 | | All NYC | 1,769 | 29 | 6 | Source: NYC Health, West Nile Virus Summary Data, 2026 Positive Results Summary, as posted when we read it on October 2, 2026. NYC Health prints no as-of date on this page. Two cautions from the Health Department itself. A human case is assigned to the borough where the patient lives, which may not be where the person was infected. And the city says the virus should be protected against in all areas of New York City, not only the ones where positive mosquitoes have been confirmed, because the virus is just as likely to be detected elsewhere. A low count in Manhattan is not a pass. ### Is NYC still spraying for mosquitoes? Nothing is scheduled right now. [NYC Health](https://www.nyc.gov/site/doh/health/health-topics/west-nile-virus-spray.page)'s Mosquito Control page, read on October 2, 2026, says under Next Scheduled Events: "There are no events currently scheduled." The most recent spraying was scheduled for parts of Manhattan on Monday, September 21, from 11:30 p.m. until 6:00 a.m., and for parts of Brooklyn and Queens on Wednesday, September 23, from 8:30 p.m. until 6:00 a.m. The page notes that the September 23 spraying was only partially completed due to low nighttime temperatures. The notice for those nights said the Health Department would apply Duet, an EPA-registered mosquito control product, using truck-mounted equipment. Earlier in September, the page lists completed spraying on September 8 and 10 in the Bronx, Queens and Staten Island, and the following week's notice scheduled Brooklyn for September 14 and Queens for September 16. If spraying resumes, the city says it will warn you first. NYC Health says it alerts the public of a pesticide application at least 24 hours before the event, and that you can register to receive direct alerts through Notify NYC. ### What should you do during mosquito spraying? Stay in if you can. NYC Health tells residents to stay indoors during spraying when possible, and to stay inside if they have asthma or other respiratory conditions. Air conditioners can remain on; the Health Department says vents may be closed or set to the recirculate function as an added precaution. On the question everyone asks, the city's own statement is that no reported diseases in people or pets have been linked with the use of pesticides in its West Nile virus control efforts since 1999. ### What are the symptoms of West Nile virus, and who is most at risk? Most infections are silent. The CDC says most people infected with West Nile virus, about 80 percent, do not develop symptoms. About 20 percent develop flu-like symptoms such as a fever with headache, body aches, joint pains, vomiting, diarrhea or rash. Fewer than 1 percent develop severe illness that affects the central nervous system, requires hospitalization, or results in death. The city's neuroinvasive row is that central nervous system category: 29 New Yorkers on the page as we read it on October 2, 2026. NYC Health adds the local timing and the local risk. Symptoms, for those who get them, usually appear between two and 14 days after an infected mosquito bite, and can take longer to start in people with a weakened immune system. People 60 years and older are at the greatest risk of severe illness. For how the virus moves between birds, mosquitoes and people, and what the season looks like nationally, our [West Nile virus explainer](https://longsleeve.com/blog/west-nile-virus) covers the CDC picture in full. ### How do you avoid mosquito bites in New York City? Start with the clock. [NYC Health](https://www.nyc.gov/site/doh/health/health-topics/west-nile-virus.page) says the mosquitoes that carry West Nile bite around dusk and dawn, and that people with severely compromised immune systems should limit their time outdoors during those hours. The CDC says the same thing more bluntly: avoid being outside between dusk and dawn, when the mosquitoes that spread West Nile virus are most active. An evening on a stoop or a patio is exactly that window. Then the city's list. [NYC Health](https://www.nyc.gov/assets/doh/downloads/pdf/wnv/2026/wnv-notice-20260908.pdf) says New Yorkers can reduce their risk of mosquito bites by using an EPA-registered insect repellent containing DEET, picaridin, IR3535 or oil of lemon eucalyptus; wearing long sleeves and pants when outdoors in areas with high mosquito activity; and making sure windows and doors have properly fitted screens. Our [field guide](https://longsleeve.com/facts) puts picaridin, DEET, oil of lemon eucalyptus and citronella side by side. The Health Department also tells New Yorkers to eliminate standing water around their homes, including water that collects in buckets, flowerpots, birdbaths, tarps, gutters and other containers, and standing water can be reported by calling 311. If the water is yours, the [CDC's once-a-week routine](https://longsleeve.com/blog/standing-water-mosquito-control) is the fix; if it is a neighbor's or a vacant lot's, 311 is the number. ### When does West Nile season end in New York? October, by the city's own calendar. NYC Health says mosquito season in New York City occurs between April and October, and the [CDC](https://www.cdc.gov/west-nile-virus/about/index.html) says people get infected during mosquito season, which starts in the summer and continues through fall, typically June through October. The CDC says diagnoses typically peak in late August to early September. In a September 10 spraying notice, NYC Health Commissioner Dr. Alister F. Martin put it this way: "Mosquito season isn't over just because summer is winding down." The New York State Department of Health considers West Nile virus endemic in the state, generally found in at least part of it each summer, so this is a yearly pattern rather than a one-off. Our [mosquito season guide](https://longsleeve.com/blog/mosquito-season-by-region) explains what actually ends a season. ### What should you do if you think you have West Nile virus? Call your doctor. NYC Health says to contact your doctor if you develop West Nile symptoms, and that a doctor can run a blood test to determine whether you are infected. The [CDC](https://www.cdc.gov/west-nile-virus/symptoms-diagnosis-treatment/index.html) says to seek immediate medical attention for high fever, neck stiffness, muscle weakness, confusion or tremors. Know the limits going in: NYC Health says there is no treatment for West Nile and most people who become infected get better on their own, and the CDC says no licensed vaccines or medicines are available to prevent West Nile virus disease in people. NYC Health's line is simple: if you develop West Nile symptoms, contact your doctor. For the symptoms on the CDC's list, go now. ### Common questions **Is the mosquito spray harmful to people or pets?** NYC Health's statement is that no reported diseases in people or pets have been linked with the use of pesticides in its West Nile virus control efforts since 1999. Its 2026 truck spraying notices, most recently for September 21 and 23, named Duet, an EPA-registered mosquito control product applied with truck-mounted equipment. The city still tells residents to stay indoors during spraying when possible, and to stay inside if they have asthma or other respiratory conditions. **What time of day do West Nile mosquitoes bite in New York City?** Around dusk and dawn, according to NYC Health, which says people with severely compromised immune systems should limit time outdoors then. The CDC 's guidance is to avoid being outside between dusk and dawn, when the mosquitoes that spread West Nile virus are most active. **How do I report standing water in New York City?** Call 311. NYC Health says standing water can be reported that way, and asks New Yorkers to eliminate it around their own homes first, including water in buckets, flowerpots, birdbaths, tarps, gutters and other containers. If you have already been bitten, our guide to treating mosquito bites covers what helps. **How many West Nile virus cases has NYC reported in 2026?** As posted on NYC Health's Summary Data page on October 2, 2026: 29 cases of West Nile neuroinvasive disease and 6 cases of West Nile fever, with positive blood donors tracked separately and not counted. The state's report dated September 28, 2026 listed 34 New York City cases, and the state says its New York City data are derived from the city health department's website, so the city page is the primary count. **Is NYC still spraying for mosquitoes?** Nothing is scheduled as of October 2, 2026. NYC Health's Mosquito Control page says there are no events currently scheduled. Its most recent spraying was scheduled for September 21 in parts of Manhattan and September 23 in parts of Brooklyn and Queens. The city says it alerts the public at least 24 hours before a pesticide application. ### About Longsleeve The city's repellent guidance names active ingredients, not brands, and picaridin is one of the four it lists. Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). Its label lists up to 14 hours of protection from mosquitoes and ticks, including mosquitoes that may transmit West Nile virus. None of this is medical advice. If you develop a rash or a fever after a bite, call your doctor and tell them what bit you. ### Related reading - [West Nile Virus in the U.S.](https://longsleeve.com/blog/west-nile-virus). How Culex mosquitoes and birds move the virus, and the CDC's national picture. - [Standing water and mosquitoes](https://longsleeve.com/blog/standing-water-mosquito-control). The CDC's once-a-week container routine. - [Mosquito season by region](https://longsleeve.com/blog/mosquito-season-by-region). What actually ends a season, and why New York runs into late fall. - [Mosquito bite treatment](https://longsleeve.com/blog/mosquito-bite-treatment). What helps, what does not, and when to see a doctor. - [The field guide](https://longsleeve.com/facts). Species, ranges, and four repellent actives side by side. ### Sources 1. NYC Health, West Nile Virus Summary Data. [https://www.nyc.gov/site/doh/health/health-topics/west-nile-virus-reports.page](https://www.nyc.gov/site/doh/health/health-topics/west-nile-virus-reports.page) 1. CDC, West Nile Virus Current Year Data (2026). [https://www.cdc.gov/west-nile-virus/data-maps/current-year-data.html](https://www.cdc.gov/west-nile-virus/data-maps/current-year-data.html) 1. CDC, About West Nile Virus. [https://www.cdc.gov/west-nile-virus/about/index.html](https://www.cdc.gov/west-nile-virus/about/index.html) 1. NYC Health, Notice of September 8 and September 10 Mosquito Spraying (PDF, posted September 4, 2026). [https://www.nyc.gov/assets/doh/downloads/pdf/wnv/2026/wnv-notice-20260908.pdf](https://www.nyc.gov/assets/doh/downloads/pdf/wnv/2026/wnv-notice-20260908.pdf) 1. NYC Health, Mosquito Control (spray schedule). [https://www.nyc.gov/site/doh/health/health-topics/west-nile-virus-spray.page](https://www.nyc.gov/site/doh/health/health-topics/west-nile-virus-spray.page) 1. CDC, Symptoms, Diagnosis, and Treatment of West Nile Virus Disease. [https://www.cdc.gov/west-nile-virus/symptoms-diagnosis-treatment/index.html](https://www.cdc.gov/west-nile-virus/symptoms-diagnosis-treatment/index.html) 1. NYC Health, West Nile Virus. [https://www.nyc.gov/site/doh/health/health-topics/west-nile-virus.page](https://www.nyc.gov/site/doh/health/health-topics/west-nile-virus.page) 1. CDC, Preventing West Nile Virus. [https://www.cdc.gov/west-nile-virus/prevention/index.html](https://www.cdc.gov/west-nile-virus/prevention/index.html) 1. New York State Department of Health, West Nile Virus. [https://www.health.ny.gov/diseases/west_nile_virus/](https://www.health.ny.gov/diseases/west_nile_virus/) 1. New York State Department of Health, Statewide Mosquito-Borne Disease Activity Report, September 28, 2026 (PDF). [https://www.health.ny.gov/diseases/mosquitoes/reports/2026/docs/mbi_report_2026_mmwr38.pdf](https://www.health.ny.gov/diseases/mosquitoes/reports/2026/docs/mbi_report_2026_mmwr38.pdf) 1. NYC Health, Notice of September 21 and 23 Mosquito Spraying (PDF, posted September 18, 2026). [https://www.nyc.gov/assets/doh/downloads/pdf/wnv/2026/wnv-notice-20260921.pdf](https://www.nyc.gov/assets/doh/downloads/pdf/wnv/2026/wnv-notice-20260921.pdf) 1. NYC Health, Notice of September 14 and 16 Mosquito Spraying (PDF). [https://www.nyc.gov/assets/doh/downloads/pdf/wnv/2026/wnv-notice-20260914.pdf](https://www.nyc.gov/assets/doh/downloads/pdf/wnv/2026/wnv-notice-20260914.pdf) Last reviewed 2026-09-06 · every claim on this page is sourced above ## West Nile Virus: Culex Mosquitoes, Symptoms, Season, Prevention URL: https://longsleeve.com/blog/west-nile-virus > How West Nile virus spreads through Culex mosquitoes and birds, who is at higher risk, what CDC says about symptoms, seasonality, and bite prevention. Source: https://longsleeve.com/blog/west-nile-virus By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 6, 2026 · Updated September 9, 2026 West Nile virus is the leading cause of mosquito-borne disease in the contiguous United States. Culex mosquitoes carry it after feeding on infected birds. Most infections cause nothing at all: the [CDC](https://www.cdc.gov/west-nile-virus/signs-symptoms/index.html) puts it at 80 percent with no symptoms, about 20 percent with a fever, and less than 1 percent with severe illness affecting the central nervous system. **Update, October 2, 2026:** West Nile is active in New York City this season. For the borough counts, where the city's spraying stands, and what NYC Health says to do, read [West Nile virus in NYC, 2026](https://longsleeve.com/blog/west-nile-virus-nyc). Every claim below traces to CDC and EPA sources, listed in full at the end. ### What is West Nile virus? West Nile virus is "a member of the family *Flaviviridae*, genus *Flavivirus*," per the CDC. Surveillance authors note it "was first detected in the Americas in 1999." **Short answer:** West Nile virus is the leading cause of mosquito-borne disease in the contiguous United States. *Culex* mosquitoes pick it up from infected birds and can spread it to people. CDC guidance says about 80 percent of infected people have no symptoms, about 20 percent develop fever, and less than 1 percent develop severe illness affecting the central nervous system. West Nile is a nationally notifiable condition, reported to the CDC through a system called ArboNET. As of August 4, 2026, the CDC's current-year dashboard listed a preliminary 143 cases for 2026, including 99 neuroinvasive cases, across 23 states. ### Which mosquitoes spread West Nile virus, and how? The [CDC](https://www.cdc.gov/west-nile-virus/causes/index.html) describes the natural cycle plainly: "In nature, West Nile virus cycles between mosquitoes (especially *Culex* species) and birds." Mosquitoes pick up the virus from infected birds, and "after about a week, infected mosquitoes can spread the virus to more birds when they bite." Surveillance authors name the vectors: the cycle "primarily involves *Culex* species mosquitoes, particularly *Cx. pipiens*, *Cx. tarsalis*, and *Cx. quinquefasciatus*." The CDC calls people "dead-end hosts because unlike birds, they do not develop high enough levels of virus in their bloodstream to spread the virus to uninfected mosquitoes that bite them." Culex behavior explains the exposure pattern. Per the [CDC](https://www.cdc.gov/mosquitoes/about/culex-mosquitoes.html), adult females lay eggs on "permanent standing water like ponds, edges of lakes, swamps, unmaintained swimming pools," plus containers around the home. Adults "are most active from dusk to dawn." Some "prefer to live near and bite birds," biting people "when other animals are not nearby." Bites do most of the work, but they are not the only route. The virus "can also spread through blood transfusion and organ transplantation," per the [CDC](https://www.cdc.gov/west-nile-virus/about/index.html), and rarely from mother to baby. It does not spread "through coughing, sneezing, or touching." ### What are the symptoms of West Nile virus? Symptoms usually start 2 to 6 days after an infected mosquito bites, per the CDC, but can start anywhere from 2 to 14 days, and longer in people with a weakened immune system. Then a three-way split, straight from the CDC's symptoms page: - **No symptoms.** "Most people (80%) infected with West Nile virus do not develop symptoms." - **Mild illness.** "About 20% of people who are infected develop flu-like symptoms, such as a fever with headache, body aches, joint pains, vomiting, diarrhea, or rash." Most recover completely, "but fatigue and weakness can last for weeks or months." - **Severe illness.** "Less than 1% of people infected develop severe illness that affects the central nervous system, requires hospitalization, or results in death." That last percent is the whole reason West Nile matters. The CDC says central nervous system infection "can cause inflammation of the brain (encephalitis) and the membranes around the brain and spinal cord (meningitis)," with symptoms including "high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis." And "about 10% of people who develop severe illness affecting the central nervous system die." In CDC surveillance for 2009 through 2018, 94 percent of the 12,835 reported neuroinvasive cases were hospitalized. The CDC's trigger line: "Seek immediate medical attention if you experience high fever, neck stiffness, muscle weakness, confusion, or tremors." ### Who is at higher risk of severe illness? Age is the big one. The CDC: "The risk of severe illness increases with age. For example, people 65 and older are three times as likely to develop neurologic illness than people younger than 65." Based on blood donor studies, its clinical page adds, about 2 percent of infected people 65 and older go on to develop neuroinvasive disease, against under 0.5 percent of infected people younger than 65. The other risk factors are "certain chronic medical conditions like cancer, diabetes, high blood pressure (hypertension), or kidney disease," and a weakened immune system, including from medications for cancer, autoimmune conditions, or preventing organ rejection. Outcomes track age just as sharply. Case-fatality among neuroinvasive patients was 2 percent under age 50, 6 percent at 50 to 69, and 21 percent at 70 and older. Recovery is often incomplete: the [CDC](https://www.cdc.gov/west-nile-virus/hcp/clinical-signs/index.html) reports 30 to 40 percent of hospitalized patients discharged to long-term care or rehabilitation, and more than 50 percent still having symptoms over a year later. ### Where and when does West Nile spread in the United States? Geographically, essentially everywhere in the lower 48. The CDC: "All states in the contiguous United States have reported cases of West Nile." During 2009 through 2018, 1,580 of 3,142 U.S. counties reported at least one neuroinvasive case. Risk concentrates. Over that decade, "the highest average annual incidence of neuroinvasive disease occurred in North Dakota (3.16 cases per 100,000 population), South Dakota (3.06), Nebraska (1.95), and Mississippi (1.17)." The largest raw case counts came from California, Texas, Illinois, and Arizona, and six counties inside those four states accounted for 23 percent of neuroinvasive cases nationally. Seasonally, the window is tight. The CDC: "People get infected with the virus during mosquito season, which starts in the summer and continues through fall (typically June through October). The number of people diagnosed with West Nile typically peaks in late August to early September." Surveillance agrees: 89 percent of patients in 2009 through 2018 had illness onset during July through September. Totals still swing, since "the annual number of reported West Nile cases can fluctuate widely, as a result of periodic epidemics." One caveat on every count above: the [CDC](https://www.cdc.gov/west-nile-virus/data-maps/historic-data.html) flags that mild cases "are more likely to be underreported compared to more severe disease (neuroinvasive) cases." Surveillance authors put it at 30 to 70 nonneuroinvasive cases for every neuroinvasive case reported, making the 9,034 mild cases reported only 1 to 2 percent of those expected. ### Is there a vaccine or treatment for West Nile? No, on both counts. The [CDC](https://www.cdc.gov/west-nile-virus/prevention/index.html) states: "No licensed vaccines or medicines are available to prevent West Nile virus disease (West Nile) in people." Its clinical guidance is equally blunt: "No treatment is available for West Nile virus (WNV) disease. Clinical management is supportive." Various drugs have been evaluated, but "none has shown conclusive benefit to date." Care is symptom management. For mild illness the CDC suggests over-the-counter medication like acetaminophen, hydration, and rest, while avoiding NSAIDs if you live in an area with dengue. "Antibiotics do not treat viral infections." Severe illness often requires hospitalization for "intravenous fluids, pain medication, and nursing care." One piece of good news: "Most people infected with West Nile virus are believed to have lifelong immunity." ### How does the CDC say to prevent West Nile? With no vaccine, the CDC's position is that "the best way to protect yourself and your loved ones from West Nile is to prevent mosquito bites." Its recommendations: - "Use an insect repellent registered with the Environmental Protection Agency." - "Wear long, loose-fitting shirts and pants so it is harder for mosquitoes to bite your skin." - "Avoid being outside between dusk and dawn when the mosquitoes that spread West Nile virus are most active." - "Use screens on windows and doors or air conditioning, if available, to keep mosquitoes outside." On repellents, the [CDC](https://www.cdc.gov/mosquitoes/prevention/index.html) lists six active ingredients in EPA-registered products: DEET, picaridin (known as KBR 3023 and icaridin outside the United States), IR3535, oil of lemon eucalyptus, para-menthane-diol, and 2-undecanone. It tells people to "look for an EPA registration number (EPA Reg. No.) on the insect repellent product label," which "means the company provided EPA with technical information on the effectiveness of the product." The EPA is explicit that "EPA and the U.S. Government do not endorse any product or service." CDC tick bite guidance names the same six ingredients; our [Lyme prevention guide](https://longsleeve.com/blog/lyme-disease-prevention) covers that overlap. The rest of the CDC's mosquito guidance: sunscreen first and repellent second, no oil of lemon eucalyptus or para-menthane-diol on children under 3, permethrin-treated clothing and gear (never on skin), and once a week empty, scrub, cover, or throw out items around the house that hold water. At the community level, "mosquito control professionals may use products to kill mosquito larvae (larvicides) or adult mosquitoes (adulticides)." ### What should you do if you think you have West Nile? Talk to a healthcare provider. The CDC says providers diagnose infection based on signs and symptoms, history of possible mosquito exposure, and laboratory testing, and can test for West Nile virus or other infections that cause similar symptoms. Two follow-ups people miss. Blood: "people recently diagnosed with West Nile virus infection should not donate blood or bone marrow for 120 days." Dead birds: avoid bare-handed contact with any dead animal, and use "gloves or double plastic bags to place the carcass in a garbage can." Any decision about testing or treatment belongs with your clinician. ### Where Longsleeve fits Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). Its label lists up to 14 hours of protection from mosquitoes and ticks, including mosquitoes that may transmit West Nile virus. It is fragrance-free, with [nine disclosed ingredients](https://longsleeve.com/ingredients). ### Common questions **What are the odds of getting seriously ill from West Nile?** The CDC says 80 percent of infected people develop no symptoms, about 20 percent get flu-like symptoms, and less than 1 percent develop severe illness affecting the central nervous system. About 10 percent of those die. **Is there a West Nile vaccine?** No. The CDC states that no licensed vaccines or medicines are available to prevent West Nile virus disease in people. There is also no medicine that treats it. Clinical management is supportive. **Which months carry the most risk?** The CDC says infections happen during mosquito season, typically June through October, with diagnoses peaking in late August to early September. CDC surveillance for 2009 through 2018 found 89 percent of patients had illness onset in July through September. **Can you catch West Nile from another person?** Not through ordinary contact. The CDC says the virus does not spread through coughing, sneezing, or touching. It can spread through blood transfusion and organ transplantation, and rarely from mother to baby. Blood and some organ donors are screened. ### Related reading - [West Nile Virus in NYC, 2026](https://longsleeve.com/blog/west-nile-virus-nyc). Borough counts, the September spray schedule, and the city's guidance. - [When Is Mosquito Season?](https://longsleeve.com/blog/mosquito-season-by-region). Health-department months and temperature thresholds, region by region. - [Vector-Borne Disease in the US, by the Numbers](https://longsleeve.com/blog/vector-borne-disease-numbers). One million reported cases, and what the CDC's counts actually measure. - [Standing Water and Mosquito Control](https://longsleeve.com/blog/standing-water-mosquito-control). The only home control with real evidence behind it. - [The Asian Tiger Mosquito](https://longsleeve.com/blog/asian-tiger-mosquito). A daytime biter that breeds in whatever holds water. - [The almanac of biting insects](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. More Longsleeve in your Google feed: ### Sources 1. CDC, About West Nile. [https://www.cdc.gov/west-nile-virus/about/index.html](https://www.cdc.gov/west-nile-virus/about/index.html) 1. CDC, Symptoms of West Nile. [https://www.cdc.gov/west-nile-virus/signs-symptoms/index.html](https://www.cdc.gov/west-nile-virus/signs-symptoms/index.html) 1. CDC, West Nile: Causes and How It Spreads. [https://www.cdc.gov/west-nile-virus/causes/index.html](https://www.cdc.gov/west-nile-virus/causes/index.html) 1. CDC, Preventing West Nile. [https://www.cdc.gov/west-nile-virus/prevention/index.html](https://www.cdc.gov/west-nile-virus/prevention/index.html) 1. CDC, Clinical Signs and Symptoms of West Nile Virus Disease. [https://www.cdc.gov/west-nile-virus/hcp/clinical-signs/index.html](https://www.cdc.gov/west-nile-virus/hcp/clinical-signs/index.html) 1. CDC, Clinical Treatment and Prevention. [https://www.cdc.gov/west-nile-virus/hcp/treatment-prevention/index.html](https://www.cdc.gov/west-nile-virus/hcp/treatment-prevention/index.html) 1. CDC, Data and Maps for West Nile. [https://www.cdc.gov/west-nile-virus/data-maps/index.html](https://www.cdc.gov/west-nile-virus/data-maps/index.html) 1. CDC, Current Year Data (2026). [https://www.cdc.gov/west-nile-virus/data-maps/current-year-data.html](https://www.cdc.gov/west-nile-virus/data-maps/current-year-data.html) 1. CDC, Historic Data (1999 to 2025). [https://www.cdc.gov/west-nile-virus/data-maps/historic-data.html](https://www.cdc.gov/west-nile-virus/data-maps/historic-data.html) 1. CDC, About Culex Mosquitoes. [https://www.cdc.gov/mosquitoes/about/culex-mosquitoes.html](https://www.cdc.gov/mosquitoes/about/culex-mosquitoes.html) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. CDC, Preventing Tick Bites. [https://www.cdc.gov/ticks/prevention/index.html](https://www.cdc.gov/ticks/prevention/index.html) 1. McDonald E, Mathis S, Martin SW, Staples JE, Fischer M, Lindsey NP. Surveillance for West Nile Virus Disease, United States, 2009 to 2018. MMWR Surveillance Summaries, 2021;70(1):1-15. [https://www.cdc.gov/mmwr/volumes/70/ss/ss7001a1.htm](https://www.cdc.gov/mmwr/volumes/70/ss/ss7001a1.htm) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) Last reviewed 2026-08-06 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off) ## Why Mosquitoes Bite Some People More: CO2, Odor, Heat, Color URL: https://longsleeve.com/blog/why-mosquitoes-bite-some-people > Why mosquitoes bite some people more than others, based on studies of carbon dioxide, skin odor chemistry, heat, clothing color, pregnancy, beer, and blood type claims. Source: https://longsleeve.com/blog/why-mosquitoes-bite-some-people By [Andrew Rothaus](https://longsleeve.com/about), Founder · August 6, 2026 · Updated August 16, 2026 Mosquitoes find you with carbon dioxide first, then vision, then heat and skin odor up close. The strongest evidence for why one person gets bitten more than another points to body odor chemistry, especially carboxylic acids produced by skin and skin bacteria. That trait appears stable for years and has a genetic component. ### How does a mosquito find a person? Only female mosquitoes bite, because they "need a blood meal to produce eggs," per the [CDC](https://www.cdc.gov/mosquitoes/about/index.html), which also describes the sensing hardware: antennae are "long feather-like organs that detect carbon dioxide from a person's breath and movement of air," palps "sense odor," and mosquitoes "have two large compound eyes that detect movement." **Short answer:** Mosquitoes use carbon dioxide, vision, heat, and skin odor to find people. The strongest evidence for why one person gets bitten more than another points to skin odor chemistry, especially carboxylic acids associated with skin and skin bacteria. Carbon dioxide helps mosquitoes find the neighborhood; skin odor helps them choose the address. ### Is carbon dioxide why some people get bitten more? Probably not on its own. CO2 switches the system on, but it is a generic animal signal. A 2021 review in Current Research in Parasitology and Vector-Borne Diseases notes that output varies with "metabolic rate, body mass and respiratory activity," then gives the counterargument: "it is unlikely that the variation in attractiveness to mosquitoes is due to differential production of CO2 or lactic acid precisely because of their generalist characteristics." Van Breugel's team cited work showing that given separate plumes, "Aedes followed the skin volatiles rather than the CO2." Breath gets them to the neighborhood. Skin picks the address. ### What does the strongest evidence say about body odor? The best data lives here. In a 2022 Cell paper, De Obaldia and colleagues at Rockefeller University "identified people who are exceptionally attractive or unattractive to mosquitoes." NIH described the setup: "Sixty-four volunteers wore nylon sleeves on their arms for six hours." In a round-robin among eight subjects, the top scorer had "4 times the attractiveness score of the next most attractive subject, and over 100 times greater than that of the two least attractive," and "these differences were stable over several years." The chemistry pointed one direction: "highly attractive people produce significantly more carboxylic acids in their skin emanations," specifically pentadecanoic, heptadecanoic and nonadecanoic acids plus ten unidentified compounds in that class. The limits matter just as much. Per NIH, the study "could not show whether high levels of carboxylic acids were directly driving mosquito preference, only that they were associated with attractiveness." The blend varied between people, so "there may be more than one way for a person to be highly attractive to mosquitoes," and one subject with high carboxylic acid levels was only weakly attractive. Context matters too: preference only shows up when mosquitoes have options, and someone alone in an infested area "may receive many bites, regardless of their overall attractiveness level because they are the only feeding option." ### Do skin bacteria matter? Yes, on narrower evidence. Verhulst and colleagues, in PLoS ONE in 2011, tested 48 men against *Anopheles gambiae* and found that highly attractive individuals "have a significantly higher abundance, but lower diversity of bacteria on their skin than individuals that are poorly attractive." *Staphylococcus* was 2.62 times more abundant in that group. The Cell team noted the link: "skin bacteria contribute to the pool of free fatty acids found on human skin," and skin microbiota is "remarkably stable within an individual over time." ### Is being a mosquito magnet genetic? Partly. Fernández-Grandon and colleagues tested identical and non-identical twins against [Aedes aegypti](https://longsleeve.com/blog/aedes-aegypti) in PLoS ONE in 2015. Identical twin pairs "showed a high correlation in attractiveness to mosquitoes, while non-identical twin pairs showed a significantly lower correlation," giving "a strong narrow-sense heritability of 0.62 (SE 0.124) for relative attraction" and demonstrating "an underlying genetic component." ### Does clothing color matter? There is real lab evidence, with a catch: color only counts once the mosquito has smelled CO2. A 2022 Nature Communications study tracked 1.3 million *Aedes aegypti* trajectories in a wind tunnel and found that "when encountering odor, mosquitoes become particularly attracted to hues that are dominant in human skin," in the long-wavelength range of 590 to 660 nanometers. Blocking those wavelengths "can suppress object attraction." Contrast registered too, with "mosquitoes investigating and preferring darker objects." High-contrast dark clothing is a modest lever at best. ### Do mosquitoes prefer certain blood types? This is the weakest claim in the canon. The most-cited supporting study, Shirai and colleagues in the Journal of Medical Entomology in 2004, is more equivocal than its reputation: blood group O subjects "attracted more Aedes albopictus than other blood groups (B, AB, and A) but were only significantly more attractive than blood group A subjects in 64 human landing tests." Applied directly to forearm skin, ABH antigens "did not, in general, influence the landing preference of mosquitoes among ABO blood groups." The 2021 review is blunter: the suggested association "was later refuted." A 2021 Scientific Reports paper on blood type and host-seeking in *Anopheles stephensi* was retracted in June 2022, the note citing "errors and discrepancies that could not be resolved." ### Does beer make you more attractive to mosquitoes? Two small studies say yes. Shirai and colleagues, in the Journal of the American Mosquito Control Association in 2002, tested 13 volunteers who drank 350 ml of beer and found landing "significantly increased after beer ingestion compared with before ingestion," though "ethanol content in sweat and skin temperature did not show any correlation." Lefèvre and colleagues ran a larger test in Burkina Faso, in PLoS ONE in 2010: 25 volunteers drank a litre of local sorghum beer, 18 drank water. "Water consumption had no effect on human attractiveness to An. gambiae mosquitoes, but beer consumption increased volunteer attractiveness," with orientation toward the odor trap rising to 65 percent against roughly 47 to 53 percent otherwise. Once again, "the level of exhaled carbon dioxide and body temperature had no effect." All 43 volunteers were Burkinabe men aged 20 to 43, and the drink was one litre of dolo, a sorghum beer of roughly 3 percent alcohol. The 2021 review's read is measured, that "there is some evidence showing that beer consumption could be a risk factor for mosquito bites," and wine and spirits remain untested. ### Are pregnant women bitten more? Yes, with field data behind it. Lindsay and colleagues, in The Lancet in 2000, studied 12 groups of women over three nights in The Gambia and found that "pregnant women attracted twice the number of Anopheles gambiae complex, the predominant African malaria-carrying mosquito, than did their non-pregnant counterparts," 6.33 per night against 3.1. They identified "increased heat and increased release of volatile substances from the skin surface." The 2021 review adds a behavioral factor: pregnant women "come out from under mosquito nets more often to urinate at night." If you are pregnant, take repellent questions to your clinician. ### What about garlic and vitamin B? Neither works. The 2021 review states that "contrary to popular belief, garlic and vitamin B, have no apparent effect as repellents." A controlled study found "no effect of vitamin B supplementation," and garlic showed nothing as an *Aedes aegypti* repellent "in a double-blinded, placebo-controlled trial involving humans." A 2018 study did find bananas increased attractiveness to *Anopheles* while green grapes did not, but the review cautions that "the literature on these aspects is quite scarce." ### What does the CDC recommend for preventing mosquito bites? The CDC recommends EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone, and advises looking for "an EPA registration number (EPA Reg. No.) on the insect repellent product label." The rest of its list: loose-fitting long-sleeved shirts and pants, permethrin-treated clothing and gear never applied to skin, window screens kept in repair, air conditioning if available, and weekly emptying of anything holding water. The EPA runs a searchable database of registered skin-applied repellents and is explicit that "EPA and the U.S. Government do not endorse any product or service." If ticks concern you too, see [when tick season runs](https://longsleeve.com/blog/tick-season-when). ### When should you see a doctor about a bite? The CDC explains that as a mosquito feeds "it injects saliva into your skin. Your body reacts to the saliva resulting in a bump and itching." More severe reactions can occur in children, in adults bitten by unfamiliar species, and in people with immune system disorders, with signs including large swelling, low-grade fever, hives, and swollen lymph nodes. The [CDC](https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html) says not to scratch bites and to "see a healthcare provider if symptoms worsen." ### Where Longsleeve fits Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients. Full ingredient details are on our [facts page](https://longsleeve.com/facts). ### Common questions **Do mosquitoes really prefer type O blood?** No. The most-cited study found blood group O subjects attracted more Aedes albopictus than group A subjects only, and ABH antigens applied to skin did not generally change landing preference. A 2021 review says the association "was later refuted," and a 2021 Scientific Reports paper on it was retracted in 2022. **What is the best-supported reason one person gets bitten more than another?** Skin odor chemistry. A 2022 Cell study found that people exceptionally attractive to Aedes aegypti produce significantly more carboxylic acids in their skin emanations, with a gap of more than 100-fold between the most and least attractive volunteers that held for years. It showed association, not causation. **Does holding still or holding your breath help?** Not much. Mosquitoes detect carbon dioxide and air movement with their antennae, odor with their palps, and movement with their compound eyes. CO2 detection switches on their attraction to visual features. **Can I change how attractive I am to mosquitoes?** The core trait looks stable. Researchers proposed that exceptionally high or low attractiveness is a "fixed" trait caused by factors constant over several years, and a twin study reported narrow-sense heritability of 0.62 for relative attraction. Pregnancy and, in two small studies, beer do appear to shift it. For personal guidance, talk to your clinician. ### Related reading - [How to Treat a Mosquito Bite](https://longsleeve.com/blog/mosquito-bite-treatment). Why bites itch, what helps, and when to see someone. - [The Asian Tiger Mosquito](https://longsleeve.com/blog/asian-tiger-mosquito). A daytime biter that breeds in whatever holds water. - [Our field guide to biting insects](https://longsleeve.com/facts). The sourced field guide: species, ranges, and the diseases they carry. - [Do Ultrasonic Repellers Work?](https://longsleeve.com/blog/ultrasonic-repellers). Why sound does not do what the packaging claims. More Longsleeve in your Google feed: ### Sources 1. CDC, About Mosquitoes. [https://www.cdc.gov/mosquitoes/about/index.html](https://www.cdc.gov/mosquitoes/about/index.html) 1. CDC, About Mosquito Bites. [https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html](https://www.cdc.gov/mosquitoes/about/about-mosquito-bites.html) 1. CDC, Preventing Mosquito Bites. [https://www.cdc.gov/mosquitoes/prevention/index.html](https://www.cdc.gov/mosquitoes/prevention/index.html) 1. EPA, Find the Repellent that is Right for You. [https://www.epa.gov/insect-repellents/find-repellent-right-you](https://www.epa.gov/insect-repellents/find-repellent-right-you) 1. van Breugel F, Riffell J, Fairhall A, Dickinson MH. Mosquitoes Use Vision to Associate Odor Plumes with Thermal Targets. Current Biology, 2015. [https://pmc.ncbi.nlm.nih.gov/articles/PMC4546539/](https://pmc.ncbi.nlm.nih.gov/articles/PMC4546539/) 1. De Obaldia ME, Morita T, Dedmon LC, Boehmler DJ, Jiang CS, Zeledon EV, et al. Differential mosquito attraction to humans is associated with skin-derived carboxylic acid levels. Cell, 2022. [https://pmc.ncbi.nlm.nih.gov/articles/PMC10069481/](https://pmc.ncbi.nlm.nih.gov/articles/PMC10069481/) 1. NIH Research Matters, Skin compounds associated with attractiveness to mosquitoes, November 1, 2022. [https://www.nih.gov/news-events/nih-research-matters/skin-compounds-associated-attractiveness-mosquitoes](https://www.nih.gov/news-events/nih-research-matters/skin-compounds-associated-attractiveness-mosquitoes) 1. Verhulst NO, Qiu YT, Beijleveld H, Maliepaard C, Knights D, Schulz S, et al. Composition of Human Skin Microbiota Affects Attractiveness to Malaria Mosquitoes. PLoS ONE, 2011. [https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0028991](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0028991) 1. Fernández-Grandon GM, Gezan SA, Armour JA, Pickett JA, Logan JG. Heritability of Attractiveness to Mosquitoes. PLoS ONE, 2015. [https://pmc.ncbi.nlm.nih.gov/articles/PMC4406498/](https://pmc.ncbi.nlm.nih.gov/articles/PMC4406498/) 1. The olfactory gating of visual preferences to human skin and visible spectra in mosquitoes. Nature Communications, 2022. [https://www.nature.com/articles/s41467-022-28195-x](https://www.nature.com/articles/s41467-022-28195-x) 1. Ellwanger JH, Cardoso JDC, Chies JAB. Variability in human attractiveness to mosquitoes. Current Research in Parasitology and Vector-Borne Diseases, 2021. [https://pmc.ncbi.nlm.nih.gov/articles/PMC8906108/](https://pmc.ncbi.nlm.nih.gov/articles/PMC8906108/) 1. Lindsay S, et al. Effect of pregnancy on exposure to malaria mosquitoes. The Lancet, 2000. [https://pubmed.ncbi.nlm.nih.gov/10859048/](https://pubmed.ncbi.nlm.nih.gov/10859048/) 1. Lefèvre T, Gouagna LC, Dabiré KR, Elguero E, Fontenille D, Renaud F, et al. Beer Consumption Increases Human Attractiveness to Malaria Mosquitoes. PLoS ONE, 2010. [https://pmc.ncbi.nlm.nih.gov/articles/PMC2832015/](https://pmc.ncbi.nlm.nih.gov/articles/PMC2832015/) 1. Shirai Y, et al. Alcohol ingestion stimulates mosquito attraction. Journal of the American Mosquito Control Association, 2002. [https://pubmed.ncbi.nlm.nih.gov/12083361/](https://pubmed.ncbi.nlm.nih.gov/12083361/) 1. Shirai Y, et al. Landing preference of *Aedes albopictus* (Diptera: Culicidae) on human skin among ABO blood groups, secretors or nonsecretors, and ABH antigens. Journal of Medical Entomology, 2004. [https://pubmed.ncbi.nlm.nih.gov/15311477/](https://pubmed.ncbi.nlm.nih.gov/15311477/) 1. Khan SA, Abu Kassim NF, Webb CE, Aqueel MA, Ahmad S, Malik S, Hussain T. Retraction Note: Human blood type influences the host-seeking behavior and fecundity of the Asian malaria vector *Anopheles stephensi*. Scientific Reports, June 17, 2022. [https://www.nature.com/articles/s41598-022-14546-7](https://www.nature.com/articles/s41598-022-14546-7) Last reviewed 2026-08-06 · every claim on this page is sourced above Compare all 631 EPA-registered skin repellents side by side in [The Repellent Index](https://longsleeve.com/repellent-index), our free database built from federal label data. Start with [Sawyer Picaridin Insect Repellent Lotion](https://longsleeve.com/repellent-index/sawyer-picaridin-insect-repellent-lotion) or [Deep Woods Off!](https://longsleeve.com/repellent-index/deep-woods-off)