How to Prevent a Poison Ivy Rash from Developing

Part 2 in a series on avoiding, preventing, and treating poison ivy rash.

If the urushiol oil contained in poison ivy comes into contact with your skin, you are at risk of developing a rash in response (unless you are one of the estimated 10 to 30 percent of the population who isn't allergic to the stuff).

Contact with urushiol can happen in multiple ways. The most obvious way is when exposed skin comes into direct contact with any part of the plant, including the leaves, vines, and roots.

The other common, less obvious way urushiol exposure occurs is when it gets on some other object—your dog; gardening gloves or tools; the surface of your pants, shoes, or backpack; etc.—and you then touch the contaminated item. (Urushiol oil is a long-lived substance, and can persist on an object for weeks, months, or even longer.)

And there are still other ways to become exposed. Your legs can get dosed with urushiol oil if you use a weed whacker to take out poison ivy, which disperses the oil into the air. You are also at risk if you burn poison ivy; the smoke will contain urushiol (a particularly hazard if it's inhaled, which can cause inflammation of the airway and lungs).

Stop Urushiol Before it Starts
If you know that you will likely come into contact with poison ivy—doing yard work, say—consider using Ivy Block. The lotion—which you apply like sunscreen—contains bentoquatam, a chemical that seems to effectively prevent skin reactions to urushiol oil. (It gets rave customer reviews on Amazon at least, where a 4-ounce bottle retails for $14.99.) Note that you must apply Ivy Block at least 15 minutes prior to any exposure for it to be effective.

Remove Urushiol ASAP—The Clock is Ticking
If you come into contact with urushiol, you have limited time to remove it before it penetrates the skin and initiates an allergic reaction. There's no hard-and-fast, scientifically proven length of time that this takes (at least that I could find), but it generally falls somewhere in the 15-minute to two-hour time frame. (It can depend on the thickness of the skin; which varies by location on your body.)

To remove urushiol, you'll need to wash the exposed site vigorously with soap and water. Urushiol is an oil, remember, so water alone won't effectively remove it. Alternatively, you can use commercial products like Tecnu and Zanfel, which are more effective at removing (and chemically deactivating) urushiol oil than soap and water alone, especially once urushiol has penetrated the skin. For example, a 2000 study in the International Journal of Dermatology found that Tecnu was effective 70 percent of the time versus 56 percent for a common dishwashing soap.

Decontaminate Your Stuff
It's important to wash any clothes, equipment, and pets that come into contact with poison ivy. Otherwise you may be inadvertently exposed to urushiol days or even weeks later, given that urushiol can remain active for a very long time.

And finally, in the world of future things that will be nice when they arrive, there's one product I've long dreamed of that now appears to be a step closer to reality: a spray that highlights the presence of urushiol oil so you know what to wash. Maybe someday....

Until then, prevent, wash, wash, and wash.

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 “Equipped” is an AMC Outdoors blog, written by Matt Heid.