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
You can buy many
different kinds of insect repellents. Some work better than others. DEET
provides the longest-lasting protection against mosquito bites.1
If you have a question or concern
about the use of insect repellents, or if you are pregnant or nursing, talk with your doctor.
(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 it is combined with DEET, permethrin provides even better
protection against mosquitoes. Permethrin keeps working even after you wash
your clothes. You can buy clothes that already contain permethrin (such as BugsAway, Bug Shield, or Buzz Off) to help protect against mosquito bites.
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
Read and follow all instructions on the label. The U.S. Environmental Protection
Agency (EPA) recommends the following precautions for using insect
CitationsFradin 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/.
August 20, 2012
E. Gregory Thompson, MD - Internal Medicine & W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
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