Mosquitoes: Prevention and Treatment

Professor Roy Benaroch, M.D.

Mosquitoes are more than an itchy nuisance.

a mosquito resting on a green leaf
The first step of mosquito prevention begins in your own back yard.

Though uncommon, serious diseases such as West Nile Encephalitis and dengue fever can be spread by mosquito bites in the USA. Our newest worry, Zika virus, is especially dangerous to pregnant women and their unborn babies — and there will almost certainly be US cases this summer.  Itchy mosquito bites can be scratched open by children, leading to scabbing, scarring, and the skin infection impetigo. Prevention is the best strategy.

Try to keep your local mosquito population under control by making it more difficult for the insects to breed. Empty any containers of standing water, including tires, empty flowerpots, or birdbaths. Avoid allowing gutters or drainage pipes to hold water. Mosquitoes are “home-bodies”—they don’t typically wander far from their place of birth. So reducing the mosquito population in your own yard can really help.

Most biting mosquitoes are active at dusk, so that’s the most important time to be vigilant with your prevention techniques. Light colored clothing is less attractive to mosquitoes. Though kids won’t want to wear long pants in the summer, keep in mind that skin covered with clothing is protected from biting insects like mosquitoes and ticks. A T-shirt is better than a tank top, and a tank top is better than no shirt at all!

Use a good mosquito repellent. The best-studied and most commonly available active ingredient is DEET. This chemical has been used for decades as an insect repellant and is very safe. Though rare allergies are always possible with any product applied to the skin, almost all children do fine with DEET. Use a concentration of about 10%, which provides effective protection for about two hours. It should be reapplied after swimming. Children who have used DEET (or any other insect repellant) should take a bath or shower at the end of the day.

Other agents that are effective insect repellants are picaridin, oil of lemon eucalyptus, and IR3535 (also known as ethyl butylactylaminopropionate. Tasty!) These are probably not more effective than DEET, but some families prefer them because of their more pleasant smell and feel. Other products, including a variety of botanical ingredients, work for only a very short duration, or not at all. The CDC has extensive info on these products here.

There are also yard sprayers or misters, devices that widely spray repellants or pesticides. I couldn’t find much in the way to independent assessments of these products, but there’s no reason to think they wouldn’t work. Still, I’m leery about the idea of spraying chemicals all over the place, when we know that DEET sprayed on your child is effective and safe for both child and environment.

About “Organic” or “Natural” insecticides or repellants – those are just  marketing words. Organic compounds are no more or less likely to be dangerous to people or the environment than non-organic compounds; likewise, “natural” in no way implies that something is safe or effective (or even “natural” in the sense that most people mean that term.) These words are tossed around as part of the typical salad of meaningless marketing-speak on labels. Ignore them.

There are also devices that act as traps, using chemicals or gas to attract the mosquitoes from your yard. Although I don’t have much independent confirmation that these work, they are probably environmentally friendly and safe.

Some children do seem more attractive to others to mosquitoes, and some children seem to have more exaggerated local reactions with big itchy warm welts. To minimize the reaction to a mosquito bites, follow these steps:

  1. Give an oral antihistamine like Zyrtec or Claritin, or old-school oral Benadryl (do NOT use topical Benadryl. It doesn’t work, and can lead to sensitization and bigger reactions.)
  2. Apply a topical steroid, like OTC hydrocortisone 1%. Your doctor can prescribe a stronger steroid if necessary.
  3. Apply ice or a cool wet washcloth.
  4. Reapply insect repellent so he doesn’t get bitten again.
  5. Have a Popsicle.
  6. Repeat all summer!
Professor Roy Benaroch, M.D. is Adjunct Assistant Professor of Pediatrics at the Emory University School of Medicine
His lecture series 
Medical School for Everyone: Pediatrics Grand Rounds is now available to stream on The Great Courses Plus.
This content is for informational purposes only. Communicating via this post does NOT create a doctor-patient relationship. If you have a medical concern specific to your child, contact your own pediatrician.