Bug repellents

Warm weather means joy, but it can also means bugs.

And bugs are more than just annoying: they can be dangerous. But I find that many parents are reluctant to use insect repellent because they worry about chemical exposures. So here’s what you need to know to keep your child safe and healthy this Summer.

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For those who just want the quick and dirty version, read the top section. If you’re interested in more background info, read further!

What do I really need to know?

• It is a common fallacy that natural = better.

• Yes, DEET is safe after your baby is 2 months old. Choose a product that is at least 20% DEET, but not higher than 30%. Picaridin is an alternative that works well.

• Mosquito netting is an option. For younger babies this works well, eg over the stroller. Just make sure you can still see your child (the netted ones are best) and it allows for ventilation so your child doesn’t overheat.

• Apply only as much as you need. You only need to apply the product to exposed skin (not under clothes), and avoid hands in infants and toddlers to minimize the risk of ingestion.

• Wear the right clothes. Light long-sleeved pants and shirts provide a layer of protection and mean you don’t have to use as much insect repellent.

• Apply only once a day. In general you should not need to reapply bug repellent more than once a day except in unusual circumstances.

• Don’t use suncreen/insect repellent combos. Remember, sunscreen needs to be applied every 2 hours so you would end up applying your bug repellent far more than necessary than needed if you use a combo.

• Bright colors, flowery prints and scented soaps are more attractive to bugs.

The Pediatrician Mom Tip: Apply sunscreen UNDERNEATH bug repellent the first time. After that the sunscreen will go on top.

• Using a spray increases the risk of inhalation. If you have no other option, spray in your hands first then rub on your child.

• Using wipes is an option, but they likely won’t last as long.

• Wash hands with soap and water before eating. Because kids are kids.

• Check for ticks at the end of the day. YES, EVEN IF YOU USED INSECT REPELLENT.

• Don’t use on cuts or irritated skin.

Why is bug repellent important?

Biting insects can cause more than just discomfort and itching. They can transmit infections, some of them quite serious. These are somewhat location-dependent, for example: I grew up in Malawi (Central Africa) and we were always concerned about malaria. Tick-borne illnesses were less of a problem there.

In the US, we worry about tick-borne and mosquito-transmitted illnesses (such as Lyme disease, Ehrlichia, and West Nile). Check the CDC guidelines for information on your destination if you’re planning to travel.

The best way to protect your child from any of these diseases is to use effective insect repellent, and to use it correctly (and safely). 

There are several options for effective products. DEET is probably the best studied, and is extremely effective. It is approved for >2 months, and is the main component of insect repellent products in the US. It also has a good safety profile.

Other products include Picaridin, and Oil of Lemon Eucalyptus are also considered effective, but are not as well studied. Some of the options out there may not be as reliably safe.

How does bug repellent work?

Different products likely have different mechanisms of action, and we don’t completely understand them. But in general, the concept is this: bugs are attracted to carbon dioxide, which we all naturally release as we exhale. Many repellants work by disguising the scent of the carbon dioxide..

But what about the chemicals? Can they harm my baby?

It is always worth being thoughtful and minimalist about the products we use on our children. But it is also important to think through risks and benefits accurately, and not be swayed by some of the misinformation found online. There is a common misconception that just because a product is natural or found in the environment, it is somehow safer.

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One way to limit the need for a bug repellent is to avoid unnecessary exposure using other methods.

Some of the concerns related to DEET are that it can cause skin irritation and rashes (but so can the others). DEET-associated toxicity is actually very rare, and is usually a result of ingestion rather than absorption through the skin.

The Pediatrician Mom Tip: As with all things, this is about risks vs benefits. The risk of an insect-borne illness in most cases outweighs the risk of toxicity from an insect repellent.

The deets on DEET:

DEET is considered very effective against mosquitoes and ticks. It is well-studied and safe, and is available in a wide range of concentrations.

The concentration does not reflect how potent a product is - it actually reflects the duration of action. As a ballpark, 10% DEET is effective for approximately 2h, while 20-25% DEET is effective for ~4-5h. Beyond about 30%, increasing the concentration doesn’t make as much of a difference, so I aim for between 20-25% for my own children if I’m unsure how long we’ll be out.

Choose the lowest effective concentration for the amount of time you expect to spend exposed. Keep in mind that swimming, sweating, and rain are going to decrease the effective duration.

The Pediatrician Mom Tip: For young babies, you can also put insect repellent on hats and clothes too. Just keep in mind that DEET can affect fabrics and young children sometimes suck on their clothes.

Picaridin

This is an insect repellent that is overall considered effective against mosquitoes and ticks. Concentrations of ~20% are about as effective as DEET for short periods. Picaridin is more widely used abroad, and generally considered safe.

The same principle applies: the higher the concentration, the longer the duration of action, but there is one study that showed that beyond the first hour, DEET may be superior for ticks.

Picaridin does come in wipe and lotion form, but these products usually are lower in concentration and may need to be reapplied frequently.

What about natural products?

Oil of Lemon Eucalyptus is a synthetic version of a chemical from the lemon eucalyptus plant. The active ingredient is P-menthane-3,8-diol. Although some studies indicate that it is effective against mosquitoes and gnats, other studies have shown inconsistent and lower efficacy compared to DEET or Picaridin (and likely shorter duration of efficacy). Of note: it can cause eye injury and is not recommended for children under 3 years.

The Pediatrician Mom Tip: Note that Oil of Lemon Eucalyptus is not the same as Lemon Eucalyptus essential oil.

Citronella is not considered to be as effective or long-lasting for mosquitoes compared to DEET, and it is not really effective for ticks. Citronella candles are fine as a second layer/back-up if you’re in your yard, but I would not rely on them as your primary repellent.

Other products (eg: lemongrass oil, cinnamon oil, soybean oil, sandalwood, peppermint oil, clove oil, etc) make the rounds every year as “natural alternatives” to the standards. But these are not considered effective (especially to protect from ticks), have not been studied as well, and are not regulated. Remember: just because something is natural doesn't make it safer.

What products should you use?

I use DEET or Picaridin for my own family. If you’re curious about the specific products that we buy, I link them on my Amazon favorites page.

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I also have two post on sun protection: sun protection and product recommendations.

I hope this provides some reassurance as you plan your summer fun!