Fight the Bite

by Sarah Givner, MD, MPH

Now that Memorial Day has come and gone, it’s unofficially the start of summer! That means cookouts, camping, swimming and lots of time spent outdoors. It also means lots of bugs, sweat and sun. To kickoff this summer season, we’re kick-starting a summer series about those summer pitfalls — insects, heat illnesses and sun burn.

Insect Repellents

For the majority of us, bug bites are more of a nuisance than a cause for concern, but for a sizable minority, they can be truly debilitating. Bug bites carry the potential for allergic reactions and diseases. This summer season, it’s important for you and your loved ones to use insect repellents to #FightTheBite. Of note, insect repellents only work to prevent bites from biting insects – not stinging ones, such as bees, wasps or hornets.

Insect repellents come in a variety of flavors, if you will. From aerosols and sprays to liquids, creams and sticks, they are a ubiquitous presence in nearly any drug or big box store. Wading through which ones are effective can be daunting. Thankfully, we are here to separate the wheat from the chaff.

Let’s begin by going through what products are NOT effective:

  1. Wristbands soaked in insect repellent
  2. Orally-taken garlic or vitamin B1
  3. Ultrasonic devices that emit sound waves
  4. Backyard bug zappers (that paradoxically may attract insects to your home)
  5. Bat or bird houses

While we all grew up using these products to some degree (who could forget those humming blue backyard lanterns!), they are not considered to be effective per the American Academy of Pediatrics and therefore not worth your time or expense.

Now, let’s go through the stuff that works.

DEET-based repellants:

DEET (or diethyltoluamide) is a synthetic chemical oil used in insect repellent. Developed in 1944 for use by the US Army in jungle terrain during WWII, it became commercially available for civilian use in 1957. Since then, it has become the mainstay of insect repellents and is the most common active ingredient in bug sprays the world over. Currently, DEET is considered the best defense against biting insects.

The amount of DEET in insect repellents varies from product to product, ranging from <10% to >30%. DEET-based products typically last between 2-5 hours. While products with higher DEET concentrations last longer, DEET concentrations >30% do not offer any additional benefit, and are actually contraindicated by the AAP.

Potential side effects of DEET include, based on exposure-type:

  1. Skin Exposure: Irritation, redness, rash, swelling
  2. Eye exposure: Irritation, pain, watery eyes
  3. Ingestion: Stomach upset, vomiting, nausea, and (very rarely) seizures

Of note, combination DEET-Sunscreen products are a NO-NO! They can make the SPF less effective and can over-expose your child to DEET due to the need for frequent reapplication.

Picardin-Based Products

Picardin (KBR 3023, Bayrepel, and icaridin) is another synthetic compound used in insect repellent. Designed to resemble piperine, a natural chemical used in the production of black pepper, it was first made in the 1980s. Since then, it has been widely used as an insect repellent in Europe and Australia, but has only recently crossed the Atlantic and Pacific, becoming commercially available in the US in 2005. It is used to repel mosquitos, biting flies, ticks, fleas and chiggers. The amount of picardin varies from product to product, and typically lasts between 3-8 hours depending on the concentration. The maximum concentration of this product is 20%.

Potential Side Effects of Picardin, based on exposure:

  1. Skin Exposure: Irritation
  2. Eye Exposure: Irritation, redness, burning sensation
  3. Ingestion: No toxicity has been reported in humans; however, liver toxicity has been described in rats in high doses

Essential Oil-Based Products

Essential oils are derived from plants that have natural repellent properties. This group includes both synthetic and natural oils. Some synthetic variants have durations of action similar to those of the more established DEET and Picardin while natural botanical oils typically last between 30min – 2 hours.

Oil of Lemon Eucalyptus

Oil of Lemon Eucalyptus is a synthetic version of the “pure” oil of lemon eucalyptus. Registered by the EPA in 2000, it has been shown to be effective for up to 6 hours.

Potential Side effects: Skin irritation

Of note, Oil of Lemon Eucalyptus cannot be used on children less than 3 due to the potential for skin irritation.

Natural (Non-synthesized) Plant Oils

Natural oils (including soybean, lemongrass, citronella, cedar, peppermint, lavender, geranium or geraniol, and others) are exempted from registration by the EPA. They are considered safe for human use, but their efficacy has not been well-studied. The American Academy of Pediatrics has no recommendation on their use. Reports note that they can last from between 30 min – 2 hours and may not be as effective as conventional repellents.

Potential Side Effects: Skin irritation

Permethrin-Based Products

Permethrin is a synthetic pyrethoid that mimics natural chrysanthemum extract and is used as a clothing tick repellent, killing ticks on contact. It was first registered with the EPA in 1979 for agricultural use and in 1990 as a clothing repellent for the military. Today, permethrin is commonly used in agriculture and for household pest control. It is endorsed by both the EPA and the CDC due to its safety and biodegradability. For personal use, it is ONLY to be used on clothing. Spray-on applications typically last through 5-6 washes with pretreated clothing lasting up to 70 washings! Sunlight and oxygen affect permethrin’s efficacy, so place treated garments in dark, airtight bags when not in use. Once dry, permethrin is odorless.

Potential Side Effects, based on exposure:

  1. Skin Exposure: Irritation
  2. Eye Exposure: Irritation, redness, burning sensation
  3. Ingestion: Sore throat, abdominal pain, nausea, vomiting

Ground-rules for Safe Repellent Use:

  1. Read the label and carefully follow all directions and precautions
  2. Only apply insect repellant to exposed skin or the OUTSIDE of clothes
  3. Spray repellents in open areas to avoid breathing in the fumes
  4. Help apply insect repellents on younger children; supervise older children when using these products
  5. Wash skin with soap and water to remove repellents when they return indoors
  6. Wash clothing after use with insect repellents
  7. NEVER apply insect repellents on children less than 2 months-old

Lastly, insect repellents are not the only way to protect children from biting bugs! Please keep these other tactics in mind while enjoying your outdoor summer season.

Other Ways to Protect Children from Insect Bites

  • Avoid areas known to attract flying insects, such as garbage cans, stagnant pools of water or gardens, orchards or flowerbeds
  • Dress children in lightweight pants, long sleeved shirts, closed-toed shoes and socks if going to a known insect-prone area
  • Avoid scented soaps and perfumes
  • Avoid wearing brightly-colored or floral-patterned clothing
  • Make sure home door and window screens are in good condition
  • Check your children’s skin for ticks at the end of the day
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