What Is Poison Sumac?
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Medically reviewed by Sameena Zahoor, MD
Poison sumac is a poisonous plant similar to poison ivy and poison oak. Each of these plants contains an oil called urushiol. When you come into contact with this oil, it can cause a skin rash, medically known as contact dermatitis, as well as other health problems. Millions of people in the United States experience rashes after contact with urushiol every year.
What Does Poison Sumac Look Like?
Poison sumac is primarily found in wet and swampy areas east of the Rocky Mountains in the northeast, midwest, and areas of the southeast in the U.S. The plant is more difficult to identify than poison ivy, which has a well-known distinct three-leaf pattern.
Poison sumac grows as a tall, sturdy shrub, with stems that contain clusters of around 7 to 13 leaves. Its leaves are orange in the spring, turn to green in summer, and then change back to yellow, orange, and red in the fall. The shrub is sometimes adorned with glossy, pale yellow or cream-colored berries.
Symptoms of Poison Sumac Rash
If you’ve had contact with urushiol, the oil found in poison sumac, you may develop a red, bumpy rash. Some people may also develop black spots or red streaks on the skin. The rash is usually severely itchy. It can blister and eventually start to leak fluid.
How quickly the rash develops depends on whether you've had a rash caused by urushiol in the past. If you’ve had a rash from poison sumac, ivy, or oak before, you could develop a new rash as quickly as a few hours after exposure. If you’ve never been exposed before, it can take up to 2 to 3 weeks to develop allergic contact dermatitis from the plant.
The rash is not contagious. After first developing, the rash might appear to spread to different areas of the body. These are actually new rashes developing from getting urushiol on that area of skin.
If you’ve never had a urushiol rash before, symptoms could last for 21 days or longer. If you have experienced a rash in the past, your rash will typically last for one to 14 days.
What Causes Poison Sumac Rash?
Most human skin is hypersensitive to urushiol oil. You can develop a rash if you come in direct contact with the oil found in poison sumac. The plant releases oil when it's damaged or burned.
After coming into contact with the oil, you can also accidentally spread urushiol from one body part to another for a very brief period before the oil soaks into the skin. Areas that have less oil on them can have delayed development, making it appear that an earlier rash is spreading. You cannot spread the rash itself from one body part to another, even by touching it directly.
You can develop a rash through indirect contact with urushiol, such as touching clothes, animals, or tools that have the poisonous plant oil on them. In some cases, urushiol can last on surfaces for years.
Risk Factors
You’re more likely to contract a rash from poison sumac if you frequent the areas where it grows. Many people develop the rash in the summer when they are spending more time outside. People who regularly work outside such as farmers, foresters, landscapers, gardeners, painters, roofers, pavers, construction workers, and mechanics, can be at more risk.
How to Treat Poison Sumac Rash
Although the rash from poison sumac is severely itchy, you should try to avoid itching the rash as scratching the skin could lead to infection. The blisters will go away on their own, but there are several ways you can relieve the itch as you wait for the rash to heal.
Methods you can try to reduce the itch include:
Apply a cold wet compress
Make a baking soda paste and apply it to the rash
Take an oatmeal bath
Soak the rash in an aluminum acetate wash
Take an antihistamine such as Benadaryl (diphenhydramine)
Use an over-the-counter or prescription topical corticosteroid or take prescription oral corticosteroids
Avoid scratching blisters
If the blisters are starting to leak, you can apply a skin protectant like zinc acetate, zinc carbonate, zinc oxide, or calamine to dry the blisters and soothe the skin.
Complications of Poison Sumac Rash
While complications from poison sumac are rare, it's important to get care if you need it. If you are experiencing any of these symptoms after developing a rash from poison sumac, it’s important to check in with a healthcare provider right away:
You develop a temperature over 100 degrees Fahrenheit
You notice pus, soft yellow scabs, or tenderness on the rash
You cannot sleep at night due to itching
The rash does not improve after a few weeks
The rash develops on your eyes, mouth, or genital area
The rash covers more than one-fourth of your skin
You have difficulty breathing
Swelling on your face
How to Prevent Poison Sumac Rash
If you are worried about getting the itchy, red rash that comes with poison sumac, there are a few key ways to avoid it. The first step is learning what poison sumac looks like, so you’re aware if you come across the plant.
A few ways to reduce your risk of exposure to poison sumac include:
Washing your clothes and any gardening or work tools regularly, especially if you live or work in an area where poison sumac might grow.
Wearing long sleeves and pants tucked into boots to protect yourself from brushing up against the plant.
Washing your pet if you suspect they could have come into contact with poison sumac. Make sure to wear gloves while washing them to avoid getting the oil on your skin.
If you do happen to come in contact with poison sumac, wash your skin as quickly as you can to help prevent a rash from developing. You can use rubbing alcohol, dishwashing soap, or a poison plant wash to try and remove the oil. Continue to rinse the skin to make sure the oil is gone.
A Quick Review
Poison sumac is in the poisonous family of plants that includes poison ivy and poison oak. These plants contain an oil known as urushiol, which can cause a red, bumpy rash if you come in contact with it directly. You can also be exposed to urushiol indirectly by touching clothes or other surfaces with the oil on them.
The rash can be incredibly itchy and uncomfortable, but it’s very common and easily treatable. Most cases will go away on their own, but if your rash doesn't heal within a few weeks or becomes severe, you should see a healthcare provider for additional treatment.
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