How to Avoid and Deal With a Poison Oak Rash

When asked, Is there anything you’d change about yourself? I have an easy answer: I’d be immune to poison oak. The stuff has attacked me at least a hundred times. Often it’s just an annoying rash, but one time I got it so bad that I had to take prescription drugs to keep my airway open. Then there was the time when I was river guiding and used a poison oak bush as an emergency toilet while trying to hide a savage case of Giardia from my clients. The level of discomfort I experienced still makes me squirm.

So what causes the rash? It's an allergic reaction to an oil the plant produces called urushiol. The stuff covers its leaves, branches, and vines. Urushiol is also made by poison sumac and poison ivy. About 70 percent of people are allergic to the oil, but here’s my first bit of advice: always assume you’re susceptible and do your best to prevent any contact. 

Below is my prevention system and, if need be, mitigation routine, plus some extra beta from buddies who also spend a lot of time thrashing through the woods. 

How to Avoid Getting a Rash

Identify the Plant

Jason Brooks, a field biologist and friend of mine, says the best way to identify poison oak is to look at the number and color of the leaves. Specifically “three leaves at the end of the branch, with two leaves across from each other and a terminal leaflet at the end,” he says. During the spring and fall, the leaves turn bright red; spring is when they have the highest amount of urushiol. To get a visual before you head out, download the Rashplants App, which is chock-full of high-res poison oak photos.

Assume All Oak Is Poisonous

Regular oak leaves look similar, and the two plants often live next to each other. If you see an oak, move away.

Don’t Pet Dogs that Might Have Been Exposed

I’ve had dozens of cases where I was ultracareful but still got nailed. My best guess: I brushed against a dog carrying the oil. The oil doesn’t bother their skin and loves to cling to their fur. If you have any doubts, encourage your dog to rinse off in a river or lake on the trail. Then at home, wash them with a shampoo made for greasy hair or, in a pinch, douse them with dish soap. I prefer Dawn for poison oak washing.

Cover Yourself

A physical barrier between your skin and the plant is the best way to keep yourself protected. My buddy Saylor Flett, an outdoor educator and professional guide, once donned a Tyvek painter's suit while hiking to a climb in the Kings Canyon area of the Southwestern Sierras, because the trail was an ocean of poison oak. It worked, even if he was miserable doing it.

Brooks uses Carhartt’s double front work pants, and I like a lightweight longsleeve UPF top like the REI Sahara Long Sleeve Shirt. If it’s too hot to wear double-layer pants, I suggest covering your legs with mud. (Seriously.)

If it’s raining, moisture can carry the oils through your clothing and onto your skin. To prevent that, I hike in waterproof pants like the Columbia Outdry PFGs. Both Flett and Brooks suggested removable gaiters like the Outdoor Research Men’s Verglas, which are more breathable and can be taken off once you’re out of the danger zone.  

Wash Your Clothes

If my wife touches poison oak with one finger, it can spread all over her body. So as soon as I get home, I throw all my potentially tainted clothes in the washer. I recommend washing those clothes by themselves in cold water with a regular detergent.  

Wash Your Body

If I suspect I’ve come into contact, I try to wash off in the nearest water source, whether it's a lake, river, or mud puddle. If I have to wait until I get home, I take a cold shower and scrub myself with a soap like Tecnu, which is made to trap and remove oils. Dawn dish soap also works. Note: if you’re washing off in the backcountry, make sure to use a biodegradable dish soap like this one from Seventh Generation and keep the suds at least 500 feet from any body of water to safeguard aquatic life.

Take Certo Fruit Pectin

Some people swear that eating Certo Fruit Pectin can help prevent a rash, although it didn’t work for me. 

How to Deal With a Rash Once You Have It

Leave It Alone

Brooks taught me that the best way to deal with a regular poison oak rash is to pretend like it’s not there. (Seek medical help, however, if it’s swelling your eyes shut, swelling around your neck, or otherwise affecting your breathing.) I’ve found that if I don’t touch the rash or put anything on it, the irritation disappears almost twice as fast. “It’s called mental toughness,” Brooks says.

If You Have to, Use Calamine Lotion or Aloe

If the itch is driving you crazy, calamine lotion can help. Aloe vera gel also soothes the itch and is less astringent than calamine. But again, I've found that putting anything on top of the rash prolongs the suffering.