Plants have their own ways of protecting themselves. Unfortunately, some of those methods aren’t always safe for humans — as anyone who’s experienced a painful rash from poison ivy, oak or sumac knows.
Jane Sennett, DO, an emergency medicine physician at Atlantic Health, shares more about these irritating plants, including how to spot them, protect yourself and, if you do get exposed, ease symptoms.
What are poison ivy, oak and sumac?
Poison ivy, poison oak and poison sumac are woody plants that are found throughout the continental U.S. While it’s possible to encounter poison oak or sumac in New Jersey, the poison ivy plant is the far more common menace in the northeast. These plants, which are all related to each other, can appear as a vine or bush.
“These plants developed urushiol, an oily resin found in every part of the plant, for defense against microbes, not to irritate humans,” says Dr. Sennett. “Although it’s not meant to harm humans, between 85-90% of humans are allergic to it, and this allergic reaction gets worse with more exposure.”
How does the oil from poison ivy, oak and sumac spread?
The rash from poison ivy, oak and sumac does not spread and is not contagious. However, urushiol tends to stay on the skin, which is why it is so important to wash with soap and water as quickly as you can to avoid transferring the oil to new parts of your body or to other people you encounter. Urushiol can also linger on clothes, gardening tools, animal fur and even dead plants.
This rash first appears as a red, blotchy area one to three days after exposure. After a few days, it may blister and crust over. These rashes often last up to two weeks. Though the rash is painful, it usually heals on its own. Nonprescription topical agents can often help reduce symptoms.
Dr. Sennett warns against scratching the rash, which can lead to a secondary infection. She also cautions against inhaling smoke from burned poison ivy, oak or sumac, since urushiol can be aerosolized and cause a severe — sometimes deadly — reaction in the lungs.
How to treat poison ivy, oak and sumac
Urushiol takes 10-15 minutes after exposure to seep into the skin. If you’ve been exposed, wash the area with soap and water, dish detergent, or, in a pinch, isopropyl alcohol (never apply alcohol to the rash once it’s blistered) to get the oil off.
Rashes from poison ivy, oak and sumac are treated the same. You can ease symptoms with at-home treatments like:
- Cool compresses
- Calamine lotion (not Caladryl lotion, which contains Benadryl and can make the rash worse)
- Cortisone cream (taking care to avoid the eyes and mouth)
- Oral antihistamines
- Topical products like Zanfel and Tecnu to remove urushiol
Your doctor may also suggest a course of steroids to relieve pain and itching.
Most patients don’t need to seek immediate care for exposure to these plants. However, talk to your doctor right away if you have:
- Difficulty breathing
- Exposure to the eyes, mouth or genitals
- Fever
- Swelling or pus around the rash
How to prevent poison ivy, oak and sumac exposure
According to Dr. Sennett, the most important thing you can do to avoid poison ivy, oak and sumac is to know your area and if these plants are present there. Be sure to:
- Check for poisonous plants before making a bonfire or collecting firewood.
- Pull long hair back.
- Use vinyl gloves when working outdoors, since leather gloves can absorb urushiol.
- Wear long sleeves and pants.
- Shower within 10-15 minutes of suspected exposure. Avoid hot water, which can open your pores and allow urushiol to seep in.
- Wash all clothes, gloves, tools and pets right away.
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