by Paul Auerbach, M.D.
reposted with permission from the Medicine for the Outdoors Blog
There is a plethora of insect repellents on the market. Many of the newer repellents are intended to replace DEET (N,N diethyl-m-toluamide), which is an excellent and reliable repellent, but which carries a distinctive odor, can dissolve certain fabrics, and has been associated with rare reports of toxicity when used in high concentrations. Newer insect repellent choices include picaridin, which is advertised to be odorless, nontoxic, and non-injurious to clothing and tents. Wanting to give it a try, I carried a bottle of
Cutter Advanced Insect Repellent (With Picaridin!) on a fishing trip this past summer to British Columbia. The main component in this product is picaridin 7%.
In previous years, I have relied upon DEET, namely,
DEET PLUS Composite Insect Repellent Lotion from Sawyer Products, which contains as its main component 17.5% DEET, and which has always been very effective. I have been using this product for years, because I continue to replenish my first aid kid from a supply I obtained nearly a decade ago. Despite this period of time, the repellent continues to perform very well and with no apparent decrease in its effectiveness.
The Cutter Advanced Insect Repellent with picaridin was easy to apply and, as advertised, was colorless and odorless. However, in my subjective, one-person observation, it wasn't as effective against the mosquitoes at our camp as was DEET. I took care to carefully apply the picaridin-containing spray to the exposed skin on my forearms, hands, face, neck, and legs, but found that I continued to be bitten by mosquitoes. The spray worked to a certain degree, as I did receive as many bites as I suffered without using the spray, but on many occasions, I needed to add the DEET Plus lotion in order to keep the mosquitoes off my skin. Furthermore, when I used DEET Plus alone instead of the picaridin spray, the former seemed to be much more effective.
Does this mean that there is no role for picaridin? Not at all. It certainly lessened the number of mosquito bites, and it is true that it is easy to apply and sports the physical characteristics as advertised. However, I have heard from a few others that their experience with picaridin has been the same, namely, that it seems to be less effective when the mosquitoes are plentiful and/or voracious, and that if an application is not perfect (e.g., a patch of skin is not treated), the mosquitoes are not repelled by picaridin in the vicinity (e.g., on treated skin) to the same degree that they might be if DEET had been used.
My recommendation at this time is that picaridin has a place as a mosquito repellent, but the user should be aware that if there is a serious concern about mosquito bites (e.g., with transmission of disease, such as West Nile virus or malaria), one should still be utilizing a DEET-containing product, use mosquito netting, pre-treat clothing with permethrin, and so forth.
PLEASE remember to preview the 25th Anniversary & Annual Meeting of the Wilderness Medical Society, which will be held in Snowmass, Colorado July 25-30, 2008.