The Differences Between Poison Ivy, Poison Oak, and Poison Sumac
Learn how to recognize these pesky plants, where they grow, how to avoid them, and how to treat your child's rash if she comes into contact with any of them.
Poison ivy, oak, and sumac are pests. Period. And if your child comes in contact with one of them, he could be itching and uncomfortable for weeks. As a preemptive strike, here's a quick guide to these plants, including how the three plants differ and where each typically grows.
How to Spot the Plants
All three of these plants are made of compound leaves—multiple leaflets that make up one leaf—so when you're trying to identify poison ivy, oak, or sumac, it's actually the number of leaflets that you should count. 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.
You may have heard the saying "Leaves of three, let it be." But this isn't always helpful because many plants with three leaves fall into that description and don't cause a reaction, says Dr. Levine. More specifically, each of the three glossy leaflets usually has jagged edges that come to a point. (That's what's pictured here.) Eastern poison ivy grows as a rope-like vine and can be found all along the East Coast, as well as in the Midwest and 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. Both versions of the plant can produce green or yellow flowers and white to green-yellow or amber berries. The leaves are usually shiny green but can change to orange-red with hints of yellow in the fall.
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 edges of the fuzzy leaflets tend to be more tooth-like than poison ivy and the plant can yield clusters of green-yellow or white berries. Also, the plant can grow as a low shrub or vine and matches the colors of other changing foliage. Poison oak isn't as widespread as poison ivy and is usually found along the West Coast (Pacific poison oak) or in the Southeastern states (Atlantic poison oak.)
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, oval in shape 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.
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 wreck havoc just about anywhere—in backyards, parks, fields, wetlands, forests, and along streams and the side of the road.
The Rash and How to Treat It
Should your child come in contact with any of these plants, the one thing that will be the same is the rash. "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 oil that is the irritant common to all three." When someone brushes up against one of these poisonous plants, the urushiol oil touches the skin and causes an allergic reaction that manifests itself in the form of an itchy, blistery rash.
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 of the rash. However, you should clean the exposed area with soap and lukewarm water as soon as possible. “The oils can be completely washed off 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. If a rash does develop, you’ll typically see it within 24 to 48 hours. 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.
Protection 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, to your child's skin—it can provide 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.
How to Get Rid of the Plants
If you're thinking of burning them, don't. The smoke you inhale could cause severe allergic respiratory problems. So, for removal, you have a couple of options. The first is to simply hire a professional who will come, suited up in protective gear, and pull the plant, shrub or vine up by the roots. The other option involves you coming in close contact with the plant, and therefore putting yourself at risk for exposure. However, there are some herbicides that can be used to treat ivy, oak, and sumac, which can potentially kill the plant. (Note that the herbicide will also usually kill any other plants in the area as well, so they have to be pulled away from other plants.) But by leaving the roots intact, there's always a chance of re-growth.
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