Insect Repellent Basics

This time of year is perfect for outdoor activities like hiking, camping, fishing, and exploring. It is also insect season. Nicholas Seman, DO, PPG – Family Medicine, provides important details on which insect repellent to choose to prevent unwanted bites, how to apply it, and why it’s so important in the warmer months.

In what situations and/or environments should we apply insect repellent?

Insect repellent should be applied if you are outdoors where you may be exposed to a biting insect that can transmit disease.

Are there certain varieties of insect repellents that you recommend?

As a general rule, if you are going to be exposed to a higher concentration of biting insects, it is better to use a product containing between 10 and 35% DEET. DEET concentrations higher than this should be reserved for situations where the insect infestation is high, the repellent may be partially washed off, or the time spent outdoors will exceed three to four hours.

If possible, microencapsulated formulations are preferred as they will provide protection for a longer period of time with lower concentrations of active repellent. Alternatively, 20% picaridin is a reasonable alternative for people wishing to avoid the unpleasant characteristics of DEET and who are willing to accept a somewhat shorter-acting repellent.

Other repellents have been studied but the results are inconsistent, so current recommendations are DEET or picaridin. Permethrin applied to clothing has also been used and remains relatively useful, but resistance is developing. Clothing treated with permethrin and DEET repellent used in combination in areas with high concentrations of biting insects appears to provide the best overall protection.

Are any of the ingredients in the insect repellent potentially harmful to our health?

Picaridin has an excellent safety profile. It is odorless, non-stick and non-greasy. It does not irritate skin, stain fabrics or degrade plastics. DEET, on the other hand, has a low risk of causing skin irritation, allergic reactions and, very rarely, neurotoxicity. DEET is not a carcinogen, but it can damage some plastics as well as clothing made from synthetic fibers, such as spandex or rayon.

How often should people apply insect repellent?

If you sweat a lot, swim or get water on the treated areas, it’s not a bad idea to reapply. Otherwise, one application of DEET should provide three to four hours of coverage, and picaridin should provide one to two hours of protection against ticks and three to four hours against mosquitoes.

Are there different considerations based on age?

DEET should not be used on people under 2 months old. Pregnant women can safely use repellents, as would anyone who is not pregnant.

How should people apply insect repellent?

Avoid spraying DEET directly on the face. Spray first in the hands then apply on the face avoiding the eyes and the mouth. For children, avoid applying the spray to the hands or fingers, as they usually have the fingers around their eyes or in their mouths. Also avoid spraying DEET under clothing. Do not apply DEET to open wounds, cuts or skin abrasions. Use only the amount of repellent needed.

Why is it important to use insect repellent?

Insects are vectors for many types of disease. These can be quite mild to something serious like West Nile virus or Zika virus, among many other illnesses that can lead to serious complications. Tick-borne illnesses are also a major concern, especially as we see Lyme disease continuing to become more common in our area within our tick population.

If you are going to be exposed to biting insects, consider wearing protective clothing and using insect repellent to prevent bites. If you find a tick embedded in your skin, carefully remove it and discard the insect and contact your healthcare provider as soon as possible. Please also contact your health care provider with any additional questions or concerns and they will be happy to assist you.

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