With summer around the corner, a very common question I get in the office is about bug safety, how can bites be prevented, what insect repellants are effective and safe? The primary concern of most families is protection from mosquitos and ticks that can be vectors for West Nile virus and Lyme disease.
There are some simple but important steps to take to minimize exposure to biting insects. Avoid using fragranced products and bright colors/floral print clothing that can attract insects or arthropoda . Try to avoid areas where insects nest such as stagnant standing water or gardens in full bloom especially at dusk. Wear long sleeved shirts and pant legs tucked into socks to decrease risk of tick attachment. Examine the skin after being outdoors. In addition to these simple steps, there are several repellant options available to protect your family from insects that transmit disease as you enjoy exploring nature and have fun in the sun.
The CDC advises use of products containing active ingredients that have been registered with the EPA. An EPA registration number indicates the materials have been evaluated for efficacy and human safety. This means that when used as directed the EPA does not expect the ingredients to cause significant adverse effects to human health or the environment. Currently products the CDC finds to be most effective contain the active ingredients DEET, Picaridin, and Lemon Eucalyptus oil.
DEET (N,N-diethyl-m-toluamide) is considered the "gold standard" in repellants. It has been in use for more than 50 years, originally designed for jungle warfare. It has the broadest spectrum of coverage for arthropoda and the longest duration of protection. DEET is available in concentrations of 4-100%. The maximum effectiveness can be achieved at 30% but the duration of action increases as the concentration increases so 7% DEET product provides about 90 minute protection while 30% DEET product provides about 5 hrs and 100% DEET provides 12 hours of protection.
The AAP recommendation for repellants is DEET for individuals over 2 months old.
There are several DEET containing products available including some combination products with sunscreen. Both the AAP and CDC do not recommend DEET/sunscreen products because sunscreen should be reapplied, while ideally you should choose a repellant that will give you the protection you need for the duration of your time outdoors in one application. Sunscreens should be applied first according to directions. Adverse reactions are uncommon with DEET but can include skin irritation, allergy and rare neurotoxicity. Neurotoxicity, including seizures, have been associated with inappropriate use such as oral ingestion or chronic exposure to high concentrations. However, when used as directed at appropriate concentrations (generally 30% or less) DEET is considered safe and the most effective repellant.
Picaridin (2-(2-hydroxyethyl)-1-piperidinecarboxylic acid 1-methyl propyl ester) is plant derived compound effective against mosquitos and ticks that has been used in Europe and Australia for several years before becoming available in the US in 2005.
Picaridin is available in 7, 15, and 20% concentrations. These repellants are as effective as DEET at higher concentrations but have a shorter duration of action. Picaridin is well tolerated as an odorless, non-greasy topical that has no toxicity in humans. Environmental considerations are also positive in that Picaridin does not stain or degrade fabrics. The AAP has not published an opinion on Picaridin as a repellant.
Lemon Eucalyptus oil (p-Methane-3,8-diol) is a bio pesticide. The active ingredient can be found naturally in eucalyptus leaves and twigs or synthesized as PMD. It is widely used in China and is considered about half as effective as DEET. PMD repels Mosquitos and biting flies but not ticks and is available in 10-65% solutions. Adverse reactions are rare but include eye irritation. PMD has not been studied in children under 3 years old and should not be used in this group. The AAP has not published an opinion on PMD.
In General application of insect repellant should be restricted only to exposed areas of the body and not underneath clothes. Any product should be removed with soap and water when no longer needed. When applying to the face products should be applied to hands and spread on face avoiding eyes, and hands should be washed after application. Repellant should only be reapplied if insects begin biting. All three active ingredients are considered safe for both human use and the environment if used as instructed on product labeling.
In summary, DEET is considered the most effective and longest lasting protection against mosquito and tick bites that may convey West Nile Virus or Lyme disease.
For most situations a product obtaining 10-30% DEET should be effective and can be used safely in people age 2 months and older. A reasonable alternative for those willing to accept a shorter duration of action and want to avoid the odor or stickiness that can be associated with DEET is a 20% Picaridin solution.
We hope you find this brief overview helpful and Wish you all a great safe summer!