Can Vitamin B1 Keep Mosquitoes Away - and If Not, What Soothes Bites Best?

| by The Pediatric Insider

The Pediatric Insider

© 2010 Roy Benaroch, MD

Summer has barely begun, and LeeAnn has already had enough of mosquitoes. She wants to know, “Does taking Vitamin B1 really help keep mosquitoes from biting? How much is safe for children?”

I remember a trip to the Florida Everglades as a child with school—surrounded by mosquitoes, alligators, and miles of swamp, our teachers told us that mosquitoes are a vital part of the food chain, and essential to the ecosystem. Blah blah blah.

I hate those bloodsuckers. The mosquitoes, I mean. Not the teachers.

Anyway: mosquitoes are more than an itchy nuisance. Though uncommon, serious diseases such as West Nile Encephalitis and dengue fever can be spread by mosquito bites in the USA. The itchy 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.

Biting mosquitoes are most 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. 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.

Two other agents that are effective insect repellants are picaridin (the active ingredient in Cutter Advance) and oil of lemon eucalyptus. These have no advantage over 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.

What about LeeAnn’s question about vitamin B1? Also known as thiamine, this vitamin is very safe to give to your children—it’s water-soluble, meaning that excessive amounts will come out in the urine. Several websites recommend this, but the few studies I could find showed that it wasn’t effective. It’s usually sold as 100 mg tablets, and one of these a day for a school-aged child would be safe to try.

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 antihisamine like Benadryl, Zyrtec, or Claritin (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 pediatrician 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!