By Dr. Julia Gaines MD, FAAP
Parents, remember the old days when mosquitoes were just an itchy pain in the neck? Well, those days, like the days without cell phones, seem to be over. Staph infections, West Nile virus, chikungunya, dengue fever, and now Zika virus have taken a childhood summer staple to a more concerning level. In years past, we focused our efforts on keeping kids from scratching their itchy bumps but now we would much prefer they just avoid getting bitten!
Now, I don’t want to be an alarmist – we see kids covered in mosquito bites every summer and I have yet to diagnose anything more concerning than secondary skin infections that may require oral antibiotics. But the risk that the mosquito carries a virus that can make you sick is definitely increasing. I’m not going to get into what diseases these viruses can cause – suffice it to say, we’d really just rather your child doesn’t get any of them.
So let’s talk protection!
There are two species of mosquitoes that carry diseases in the United States – the Culex mosquito which can carry West Nile virus, and the Aedes mosquito which can spread Zika virus, chikungunya, and dengue fever. The Culex is most active at dawn and dusk while the Aedes is active throughout the day. So unless your kids are playing outside at midnight, you’re out of luck. The female of both species requires a blood meal to reproduce and lays her eggs in still water. Certainly, everyone should try to eliminate any standing water on their property in kiddie pools, buckets, bird baths, flower pot saucers, etc., but it’s impossible to eliminate all standing water during a rainy Georgia summer. Clothing can help protect you, but it’s probably not practical to dress your kid in long sleeves and pants and send them out to play in 90 degree weather. We want kids to be active and play outside rather than stay glued to video games all day, so it’s time to talk bug spray.
There is a dizzying array of mosquito repellants available to buy and they range from very effective to completely useless. None of the available products actually kill mosquitoes – they all work by repelling the mosquito so she’ll go look somewhere else for her blood meal. And on that topic, there is no evidence that eating garlic or any other food will make you less likely to get bitten (vampires, yes, mosquitoes, no).
Currently, there are three active ingredients approved by the EPA for use in humans that actually work – DEET, picaridin, and oil of lemon eucalyptus. Soybean oil, IR3535, citronella, and a variety of essential oils have found to be only slightly better than nothing by which I mean they work for about 10 minutes before the mosquito finds you attractive again. Equally useless are repellant wristbands, ultrasonic products, and citronella candles. The combination sunscreens/mosquito repellants are not recommended. They need to be reapplied at different rates so it just gets confusing.
DEET is a synthetic chemical while picaridin and oil of lemon eucalyptus are derived from plants. Please remember that synthetic is not automatically bad and natural automatically good; in fact, oil of lemon eucalyptus is not safe for use in children under 3 years while DEET is. However, if you are trying avoid synthetic chemicals, picaridin has been shown to be safe and efficacious.
So what do all the numbers mean?
Is DEET 35% stronger than 10%? As it turns out, not at all! This was actually a surprise to me, but DEET is DEET is DEET. As the percentage increases, the only thing that changes is how long the product works. A spray with 10% DEET will last 1-2 hours while a product with 30% DEET will last about 8 hours. This is also true for picaridin. A product with 20% picaridin will last about 8 hours and it goes down from there. So, read your labels to see how often you need to reapply and don’t use something stronger than you need, especially with young kids.
Apply the product lightly – drowning the kid in it doesn’t protect them more than if you used a judicious hand. Spray clothing and exposed skin, not skin that is covered by clothes. To protect the face, spray the product on your hands and wipe your child’s face, avoiding the eyes and mouth. I would avoid spraying young children’s hands as you know they are going right in the mouth. It turns out the Aedes mosquito is particularly attracted to the smell of sweaty feet (I know!), so spray everyone’s feet and ankles. And plop that dirty sweaty kid in the bath at the end of the day and wash everything off.
So, to summarize, mosquitoes and their germs, bad, mosquito repellants good if you pick the right one. Since products with oil of lemon eucalyptus can’t be used in young children, to keep it simple I’d look for a product with DEET or picaridin. If you need a long lasting product (for summer camp, long hikes, etc) chose a product with 30% DEET or 20% picaridin. If you just want to protect your child when they play in the backyard for an hour, 10% of either ingredient should suffice. Unless you just want to make your child smell good while the mosquitoes are biting him, don’t waste your money on the “natural” products with citronella or other plant oils.