You can lower your chance of being bitten by an insect or spiderlike animal (arachnid) by using insect repellents. Mosquitoes, biting flies, and ticks can cause annoying bites and sometimes a serious disease. Mosquito bites can spread infections such as West Nile virus, a virus that causes swelling of the brain (encephalitis), and malaria in some parts of the world. Tick bites can cause serious diseases such as Lyme disease and Rocky Mountain spotted fever. Bites from biting flies are painful and may cause a skin infection.
You can buy many different kinds of insect repellents. Some work better than others. DEET provides the longest-lasting protection against mosquito bites.1 It is important for pregnant and nursing women to follow these tips for safe use of insect repellents. If you have a question or concern about the use of insect repellents, talk with your doctor.
DEET (N,N-diethyl-3-meta-toluamide) is the most effective insect repellent.
Picaridin is an insecticide that has been available for use in Europe for many years. It is available in the United States in a 7% concentration spray. It may work as well as DEET in repelling insects. Higher-strength concentrations that are sold in Europe protect against mosquitoes for up to 8 hours. Picaridin is odorless and does not feel sticky or greasy. It is less likely to cause skin irritation than DEET. And it does not damage synthetic fabrics or plastics. The American Academy of Pediatrics (AAP) does not recommend the use of Picaridin on children younger than age 2 months.
Permethrin is a plant-based insecticide that works on contact. You spray it on clothing and other fabrics, such as mosquito netting and tent walls. Permethrin should not be applied directly to the skin. When combined with DEET, permethrin provides even better protection against mosquitoes. Permethrin keeps working even after you wash your clothes.
P-menthane 3,8-diol. This insect repellent is commonly known as lemon eucalyptus oil. When oil of lemon eucalyptus was tested against mosquitoes found in the U.S., it provided protection similar to repellents with low concentrations of DEET. It provides up to 2 hours of protection against mosquito bites. Do not apply more than 2 times a day, and do not use this product on children younger than 3 years.
Soybean oil. Insect repellents that contain 2% soybean oil provide 1 to 4 hours of protection from mosquitoes when applied to the skin. Soybean oil is safe to use on infants and children.
IR3535. This repellent is a chemical similar to the amino acid alanine. Tests have shown that it can protect against mosquito bites for up to 1 hour.1
Citronella is a lemon-scented oil, derived from a plant, that repels mosquitoes. It is not as effective or as long-lasting as DEET. The product can be reapplied frequently to increase its effectiveness. Citronella can be found in lotions or in candles for outdoor use. Citronella applied to the skin provides 15 to 20 minutes of protection from mosquitoes. There is no scientific evidence that citronella candles are effective.
Other plant oils. Other plant oils, such as lavender and geranium, provide less than 30 minutes of protection against mosquitoes. These products aren't recommended.
There are other products advertised as mosquito repellents that don't effectively prevent mosquito bites. These include:
- Fradin MS, Day JF (2002). Comparative efficacy of insect repellents against mosquito bites. New England Journal of Medicine, 347(1): 13–18.
- Committee to Advise on Tropical Medicine and Travel (2005). Statement on personal protective measures to prevent arthropod bites. Canada Communicable Disease Report, 31: 1–20. Available online at http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/05vol31/asc-dcc-4/.
|Primary Medical Reviewer||E. Gregory Thompson, MD - Internal Medicine|
|Specialist Medical Reviewer||W. David Colby IV, MSc, MD, FRCPC - Infectious Disease|
|Last Revised||March 7, 2012|
Last Revised: March 7, 2012
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