It’s that time of year when our skin is once again barraged by the sun throughout the day and those pesky insects all night. Not surprisingly, many of my patients have been asking questions about both sunscreens and insect repellents. To that avail we have devoted this first series of educational questions to those precarious pest preventers, the “bug sprays”. Stay tuned though as we will deal with sunscreens very soon.
Here are a few of the insect repellent (“bug spray”) questions I’ve been getting.
Question: What’s the best bug spray?
Answer: I’m going to answer this without really naming any specific products but I think if you are good about reading the labels it will be helpful. There are a host of chemicals on the market for use as insect repellents. These include the most well known one DEET (or NN-diethyl-3-methylbenzamide) as well as several other less commonly known chemicals (indalone, Rutgers 612, Dialkyl phthalates). There are also some essential plant oils like citronella oil, lemon oil, eucalyptus oil and soy bean oil that can be used. In the last few years, the newest one of these to come to market is a compound called ‘picardin’ which has the effectiveness of low strength DEET but tends to be safer.
I would recommend either using a DEET containing spray or a Picardin containing spray. While the oils sound great because they are certainly going to be fairly safe, they have not shown to be very effective. Another one to avoid in my opinion is skin-so-soft. It’s great if you are in an area with only “one or two mosquitos” but really not good otherwise.
Question: Is DEET safe for children and pregnant women?
Answer: Yes, with exceptions of course. Although there are concerns that DEET can cause seizures in kids, there is no evidence to back this statement up. According to the Am. Academy of Pediatrics it should never be used in children 2 months or less and I would extend this to say that no one under 6 months. For other children use concentrations in the range of 10-30%, wash it off before they go to bed and avoid direct spray to the face. It is also safe for pregnancy (in second and third trimesters) and with breast feeding.
Problems with DEET sunscreens are that it damages certain man made materials such as rayon, spandex and some leather. It can even dissolve plastic and vinyl (I have seen this first hand on a pair of sunglasses) so avoid contact with these materials. This is where Picardin is great because it does none of the above.
Question: Are insect repellents the only thing out there?
Answer: No. As you may already know the insects are horrible in this area because of all of the rain. My real outdoors people (campers, hikers, etc.) can get a chemical spray for your clothing, shoes, tents, and other camping gear that contains permethrin. You can even find it already in some select lines of clothing. It’s a very effective adjunct to insect repellents and not only against mosquitos but ticks as well.
Question: Are the combination sunscreen/insect repellents a good choice?
Answer: No. Although I have noticed the mosquitos are out in full force during even the mid day hours there is a problem with these. Most insect repellents reduce the effectiveness of sunscreens. This could lead to inadvertent burns which nobody wants. Sunscreens are not a once and done thing if you’re going to be out all day. They need reapplication. Insect repellents don’t however require as much reapplication and therefore you may end up using too much or neglecting your sunscreen to avoid over use of the insect repellent. There are some other concerns regarding toxicity of DEET in conjunction with a sunscreen so I just don’t recommend this at all.
Hope this answers some of your questions and perhaps defeats a few of the common myths about insect repellents. Stay safe and itch free.
Brett Kockentiet MD
Affiliated dermatology and Cosmetic Surgery Center of Dublin Ohio