Choose the Best Insect Repellent
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Choose the Best Insect Repellent

summer hike In warm weather, mosquitoes, ticks, flies, and other insects become annoying pests—and potential carriers of disease. So what’s your best protection? There are things you can do:

  • Avoid cultivating insect habitats. Drain standing water where mosquitoes breed.
  • Wear long-sleeved shirts and long pants. Wear them especially at dawn and dusk when mosquitoes are most active.
  • Wear insect repellent. This is the most effective protection from insect bites.

Insect Repellent Basics

There are two kinds of insect repellents: man-made chemicals and plant-based essential oils. The best-known chemical repellent is DEET—the common name for N,N-diethyl-m-toluamide. DEET is the main ingredient in many insect repellents. Repellents with DEET have been shown to be more effective than other products in preventing mosquito bites in particular. Repellents with DEET are available as sprays and lotions.

Repellents With DEET: Are They Safe?

DEET is very safe when used according to the directions. DEET can even be used safely on children and women who are pregnant and breastfeeding.

In rare cases, repellents with DEET may cause skin reactions. However, most of these cases have happened when the product was not used according to the directions, such as applying over broken skin, and using over many days without washing in between.

If you think you have a reaction to a DEET product, wash the treated skin and contact a Poison Control Center near you: 1-800-222-1222.

Using DEET Products Safely

Check the product label for information about how much DEET the repellent contains. The more DEET a repellent contains, the longer it can protect you from insect bites. For example, a study showed that a product with 23.8% DEET gave about five hours of protection from mosquito bites. A product with 6.65% DEET gave almost two hours of protection.

When using products with DEET:

  • Always follow the instructions on the product label.
  • Do not apply repellent under clothing.
  • Do not apply repellent to cuts, wounds, or irritated skin.
  • Wash treated skin with soap and water after returning indoors.
  • Do not spray DEET products in enclosed areas.
  • Do not spray DEET products directly on your face. Spray your hands and then rub them carefully over the face, avoiding the eyes and mouth.
  • Adults are probably best served by using a 10%-30% extended-release DEET product rather than a regular release product with a higher DEET concentration; the lower concentration extended-release products decrease the potential of DEET toxicity or skin reactions.

When using products with DEET on children:

  • The American Academy of Pediatrics suggests using repellent with lower concentrations of DEET (30% or lower) on children over two months old; DEET is not recommended for use in babies under the age of two months. Consult the pediatrician if your baby needs protection from insects.
  • When using repellent on a child, apply it to your own hands and then rub them on your child. Avoid the child’s eyes and mouth and use it carefully around her ears.
  • Do not apply repellent to children's hands. (Children may put their hands in their mouths.)
  • Do not allow young children to apply insect repellent to themselves; have an adult do it for them.

Promising Alternatives to DEET

Most plant-based insect repellents use essential oils from one or more of these plants: citronella, cedar, eucalyptus, peppermint, lemongrass, geranium, and soybean. Of the products tested in a study, a soybean oil-based repellent gave protection from mosquito bites for about 1.5 hours. This is similar to a product with a low concentration of DEET (4.75%).

Use a soybean oil-based product instead of DEET if you:

  • Have had allergic skin reactions to products with DEET in the past
  • Have irritated, sunburned, bruised, or broken skin
  • Have a skin condition such as skin cancer, dermatitis, acne, eczema, or psoriasis

When using soybean oil-based repellent, reapply the product if you are outdoors for longer than 90 minutes, or if you start being bitten by mosquitoes.

Picaridin is a product developed by Bayer. It has been widely used in Europe and Australia. Its effectiveness is comparable to DEET, but it is odorless and does not irritate skin. It is also effective against other insects like fleas or ticks.

What about products that aren’t applied to the skin? Research says that garlic and thiamine (vitamin B1) are not effective.

The Best Repellent for You

Choose a repellent that you will use every time and that will give you enough protection for the amount of time you will be outdoors. If you are worried about using DEET, talk to your healthcare provider for advice. And enjoy a bug-free summer.

RESOURCES:

Centers for Disease Control and Prevention
http://www.cdc.gov/

Environmental Protection Agency Insect Repellent Information
http://www.epa.gov/pesticides/ncidod

National Pesticide Information Center
http://npic.orst.edu/

CANADIAN RESOURCES:

Canadian Public Health
http://www.phac-aspc.gc.ca/

The College of Canadian Family Physicians
http://www.cfpc.ca/

References:

DynaMed Editors. Mosquito avoidance. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/. Updated July 13, 2010. Accessed May 12, 2011.

Fradin MS, Day JF. Comparative Efficacy Of Insect Repellents Against Mosquito Bites. NEJM. 2002;347:13-18.

Goodyer L, Behrens RH. Short report: the safety and toxicity of insect repellents. Am J Trop Med Hyg. 1998;59:323-324.

Insect Repellents. American Academy of Pediatrics. Available at: http://www.healthychildren.org/English/safety-prevention/at-play/pages/Insect-Repellents.aspx. Updated May 17, 2011. Accessed May 17, 2011.

McGready R, Hamilton KA, Simpson JA, et al. Safety of the insect repellent N,N-diethyl-M-toluamide (DEET) in pregnancy. Am J Trop Med Hyg. 2001;65:285-289.

Picardin—a new insect repellent. Med Lett Drugs Ther. 2005;47:46-47.

Reregistration of the insect repellent DEET. US Environmental Protection Agency website. Available at: http://www.epa.gov/pesticides/factsheets/chemicals/deet.htm. Accessed May 1, 2005.

Robb-Nicholson C. By the way, doctor. DEET makes a mess of my fly fishing gear. I've heard there are some new mosquito repellents that don't contain DEET. Are they any good? Harv Womens Health Watch. 2005;12:8.

Roberts JR, Reigart JR. Does anything beat DEET? Pediatr Ann. 2004;33:443-453.

Scheinfeld NS. Insect repellent: more attractive to people, less attraction for insects? Cutis. 2006;77:281-282.

West Nile virus information: follow safety precautions when using DEET on children. American Academy of Pediatrics website. Available at: http://www.aap.org/family/wnv-jun03.htm. Accessed May 1, 2005.

Summer safety tips: part 1. American Academy of Pediatrics website. Available at: http://www.aap.org/advocacy/releases/summertips.cfm. Accessed May 12, 2011.

What you need to know about mosquito repellent. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/ncidod/dvbid/westnile/mosquitorepellent.htm. Accessed May 1, 2005.



Last reviewed May 2011 by Brian Randall, MD


Last updated Updated: 5/12/2011

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.


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