Sign warning of ticks to hikers in a forest. Shutterstock.

If you spend a lot of time working or playing outside or if you live in an area with a lot of tick activity, maybe you’ve considered wearing permethrin-treated clothing to keep ticks from attaching and biting. While repellents containing DEET are still the main recommendation for use on exposed skin, the insecticide permethrin is available for use on clothing only (not skin).

Permethrin-treated clothing has previously been tested and shown to be effective against mosquitoes as well as the blacklegged tick, the vector of Lyme disease. Now a new study from researchers at the Centers for Disease Control (CDC) has confirmed that permethrin also works well against the American dog tick and the lone star tick. Permethrin doesn’t quite act like a repellent that stops mosquitoes or ticks from getting on you in the first place. Instead it incapacitates any pests that do get on your clothing, hopefully before they can bite or attach.

In the CDC study, both lab-reared and field-collected ticks of the three species were exposed for varying lengths of time to 10 different types of permethrin-treated clothing available from manufacturer Insect Shield –100% cotton as well as synthetic and blend T-shirts, pants, and socks.

When the test ticks initially made contact with permethrin-treated clothing, they showed irritation, causing them to drop off of vertical treated surfaces such as a pant leg. Continued forced exposure resulted in all loss of normal movement leaving the tick unable to bite. Even better news – the blacklegged tick nymph seems to be more strongly affected by permethrin than other tick stages. This is important because the nymph is the stage most often responsible for transmission of Lyme disease as well as several other diseases.

IS PERMETHRIN-TREATED CLOTHING SAFE TO WEAR?

While EPA considers permethrin to be a likely human carcinogen if swallowed, it says that the amount allowed in manufactured clothing is too low to be a concern to humans. Tests show that permethrin-treated clothing leaches only very small amounts onto skin. One manufacturer has even developed styles to help protect pregnant women from bites and the risk of the Zika virus.

HOW TO GET PERMETHRIN-TREATED CLOTHING

(1) There are manufacturers like Insect Shield and Burlington that produce clothing that is pre-treated with permethrin. Such permethrin-treated clothing is sold primarily by stores that specialize in outdoor wear such as L.L. Bean, Orvis, and Duluth Trading. Effectiveness can vary; some products claim to remain effective against mosquitoes at 70+ washings.

(2) If you’re hard to fit, you might appreciate the fact that there are companies such as Insect Shield that will treat clothing you already own. You mail it in, they treat it and send it back.

(3) You can buy 0.5% permethrin spray to treat your own clothing, tents, boots, hats, etc. if you carefully follow the label directions and spray evenly and thoroughly. Self-treated clothing will not remain effective for nearly as many washes as manufactured clothing. The National Pesticide Information Center has info on how to do this and much more on their Permethrin Treated Clothing web page.

Bottom line? In situations where you need to prevent mosquito and tick bites, CDC recommends wearing permethrin-treated clothing — along with the use of a repellent such as DEET on exposed skin. For more on the use of skin repellents, see Do Insect Repellents Work Against Ticks? and Mosquito Repellents Tested and Rated.