If you’re itching for a summer adventure, a trip to the beach or a hike in the park might be just what you need, but watch where you step—poison ivy could be near. We typically think of this plant as lying deep in the woods, but in fact it’s most commonly found in less remote areas: the edges of your backyard, the shoulder of a highway, even a sand dune on a beach.

And as with other poisonous plants, such as poison oak and poison sumac, even just a slight brush against the poison ivy plant can deposit its oily coating—called urushiol, this is the substance that makes poison ivy “poisonous”—onto your skin. Within four hours and up to four days after exposure, you might experience redness, swelling, and severe itching. Eventually a rash often accompanied by fluid-filled blisters emerges in a line or a streaklike pattern.

“Poison ivy rashes have been getting more severe each season due to global warming and longer growth seasons with stronger urushiol production,” says Jessica Krant, M.D., a clinical assistant professor of dermatology at SUNY Downstate Medical Center in Brooklyn, N.Y., and a member of Consumer Reports’ medical advisory board. To protect yourself, follow these tips. 

What to Look For

Poison ivy grows all across the U.S.; it's less common at high elevations and in deserts. Poison ivy’s glossy flowering leaves are marked with the characteristic three-point leaflets sprouting in different directions. The edges can be smooth or jagged, and the plant can carry greenish-white berries resembling small clusters of grapes.

The plant can snake up a tree, creep along a fence, sprout through the cracks of a sidewalk, and grow low as a shrub. And as with other flowering plants, the leaf color changes with the seasons—green in the summer; yellow, orange, or red in the fall; and red with hints of green in the spring.

Poison oak has fuzzy green leaves and yellowish-white berries, and its leaves also grow in clusters of three. Poison sumac’s leaves cluster in groups of seven to 13 and have smooth edges.  

How You Get a Rash

Wearing long sleeves and long pants can help protect you from poison ivy, but coming in contact with the plant isn’t the only way you can get a rash.

Urushiol can hitchhike on other objects, such as gardening tools and gloves, clothing—even your dog’s fur—and if you touch something that’s been contaminated, the urushiol can be transmitted to you. So be sure to wash these regularly.

It’s a common belief that the rash or fluid from the blisters can be transmitted from person to person or from one body part to another. But that’s not the case. While you might notice that new blisters will crop up on different parts of your body seemingly out of nowhere, that’s because some parts of the body take longer to develop a reaction, says Krant.

In addition, the residual plant oils can linger on most surfaces until they're removed with water or rubbing alcohol, even for years, according to the U.S. Food and Drug Administration. That means you could be reinfecting yourself. 

How to Treat Poison Ivy

If you know you’ve touched a poisonous plant, the first step is to try to prevent the rash from developing by scrubbing your skin with soap and water as soon as possible, ideally within the first 15 minutes of contact, says Krant. Be sure to wash the clothes you were wearing, too. “You only have a reaction if you are actually allergic to the oil,” says Krant. Not everyone is, but you still shouldn’t take a chance.

Should you get a rash anyway, try an oatmeal bath, a cool, wet compress, some calamine lotion, or some over-the-counter cortisone cream to relieve the itch. “You can also make a paste or poultice by adding a little water to baking soda," says Krant. The rash varies in severity from person to person.

If home treatments aren’t helping, Krant says you might need a prescription-strength topical steroid cream. In fact, in one 2016 study, the only patients who reduced the days they were itchy were those prescribed both a strong topical steroid cream and a steroid injection or pill. So consider visiting your doctor if you're having trouble getting relief.