The Differences Between Poison Ivy, Poison Oak, and Poison Sumac

How do you distinguish between these poisonous plants, and what's the best way to treat rashes that appear after touching them? We spoke with experts to find out.

Poison ivy, poison oak, and poison sumac are pests—and if your child comes in contact with one of them, he'll be itchy and uncomfortable for weeks. As a preemptive strike, here's a quick guide to these plants, including how they differ and where they typically grow.

How to Spot Poisonous Plants

Poison ivy, poison oak, and poison sumac are made of compound leaves—multiple leaflets that make up one leaf—which makes them fairly easy to identify. Also, "be on the lookout for a dull, waxy sheen on the plant," says Parents advisor Jody A. Levine, M.D., director of dermatology at Plastic Surgery & Dermatology of NYC. "This is urushiol, the toxic substance that causes the reaction." This oil can be found on every part of the plants, including the stems, berries, roots, flowers, and of course, the leaves.

Hawaii and Alaska are the only two states in the U.S. that don't grow any of these poisonous plants. And although poison sumac is partial to bogs and swamps, ivy and oak can wreak havoc just about anywhere—in backyards, parks, fields, wetlands, forests, and along streams and the side of the road.

Read on for more information about identifying these poisonous plants.

Father And Son In Woods Look at Rocks In Hands
Erin Kunkel

Poison Ivy

Remember this saying: "Leaves of three, let it be!" Poison ivy has three glossy almond-shaped leaflets with jagged edges that come to a point. The leaves are usually shiny green but can change to orange-red with hints of yellow in the fall. Some plants have berries that range in color from white to green-yellow to amber.

Eastern poison ivy grows as a rope-like vine and can be found along the East Coast and Midwest, as well as some southern and western states. Western poison ivy is a shrub and grows almost everywhere in the continental U.S., excluding California and a handful of southeastern states.

Poison Ivy
Getty Images. Getty Images

Poison Oak

This rash-causing culprit also falls under the 'leaves of three' category and is a tricky one to spot. "Poison oak is very good at camouflaging itself to blend in with the plants around it," says Dr. Levine. The fuzzy leaflets have uneven, scalloped edges. The plant can also yield clusters of green-yellow or white berries.

Poison oak grows as a low shrub or vine and matches the colors of other changing foliage. It's not as widespread as poison ivy and is usually found along the West Coast (Pacific poison oak) or in the Southeastern states (Atlantic poison oak.)

Poison oak
Mark Rightmire/MediaNews Group/Orange County Register via Getty Images. Mark Rightmire/MediaNews Group/Orange County Register via Getty Images

Poison Sumac

Compared to ivy and oak, this plant is quite different. "Poison sumac takes on a 'fern-like' appearance, growing between seven and 13 leaflets on a reddish stem," says Dr. Levine. The green leaflets, which are oval-shaped with a pointy top, tend to run in pairs up the stem. This tall shrub or small tree flourishes in bogs and swamps, may have glossy pale-yellow or cream-colored berries, and can change colors with the seasons. Poison sumac is found in nearly the entire east coast, parts of the Midwest, and in a handful of southern states.

Poison Sumac Plant
Peder Digre/Shutterstock

My Kid Touched a Poisonous Plant—Now What?

Should your child come in contact with any of these plants, clean the skin with soap and lukewarm water. "The oils can wash off completely if you do this within 15 minutes of exposure," says Renee Miller, R.N.,of Vanderbilt University Medical Center's Poison Control Center, in Nashville.

Rashes usually develop within 24 to 48 hours, and they'll be itchy and blistery. "If you were theoretically in a place where all three plants were together and you brushed all three plants, the rash would be indistinguishable," says Parents advisor Lawrence F. Eichenfield, M.D., professor of pediatrics and dermatology at University of California, San Diego and chief of pediatric and adolescent dermatology at Rady Children's Hospital. "It's the urushiol oil that is the irritant common to all three."

Small rashes from contact with these plants can be treated at home with wet compresses, cool baths, and calamine lotion—all of which will relieve the itch. Antihistamines can help with itching, but consult your pediatrician about further treatment. If your child is severely allergic to the plants, she can develop life-threatening anaphylaxis that requires immediate medical attention.

How to Protect Against Poisonous Plants

There are a couple of things you can do to reduce the risk of exposure. You can apply Ivy Block, a topical lotion sold OTC at most drugstores, for added protection against poison ivy, oak, and sumac. The key ingredient is bentoquatam and it helps prevent the skin from absorbing urushiol oil (note that it's not for children under age 6). Also, if you know your child will be playing in an area where he's likely to brush up against a lot of greenery, then insist he wear a long sleeve shirt and long pants tucked into boots, if possible.

Parents might also want to get rid of poison ivy, poison oak, and poison sumac from their yards. Never burn the plants; the smoke you inhale could cause severe allergic respiratory problems. Here are two safer options for removal:

  • Hire a professional who will pull the plant, shrub, or vine up by the roots.
  • Remove the plants yourself with proper protective gear .
  • Use herbicides that treat ivy, oak, and sumac. Note that the herbicide will also kill any other plants in the area, and leaving the roots intact comes with a chance of regrowth.
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