CDC
- A poison sumac rash is usually accompanied by redness, swelling, blisters, and an intense itch.
- After you come in contact with poison sumac, you need to clean the area with soap and water.
- Then, you should try anti-itch creams like calamine or hydrocortisone cream or take an oatmeal bath.
- Visit Insider's Health Reference library for more advice.
Poison sumac is a shrub or small tree that grows in wet, wooded areas of the Eastern United States. Poison sumac grows year-round and any part of the plant, including the leaves, stems, and berries, can cause an allergic reaction.
Touching the plant triggers a rash that usually isn't dangerous, but can be very uncomfortable and may last for weeks. If you get a poison sumac rash, there are several remedies you can try at home that may reduce your symptoms and help you heal more quickly.
Poison sumac rash symptoms
Poison sumac works the same way as poison ivy and poison oak – all three plants contain an oil called urushiol that causes an allergic reaction in most people.
You can get a poison sumac rash by touching the plant directly or by touching something contaminated with the oil, like clothing.
After coming into contact with poison sumac, you will usually develop a rash on your skin with symptoms like:
- Redness
- Swelling
- Intense itch
- Blisters
"If it's your first time being exposed to this chemical, it might take up to 2 weeks for the rash to appear," says Troy Madsen, MD, a professor of emergency medicine at the University of Utah.
But if you've had a previous reaction to poison sumac, your immune system will be more familiar with the plant and a rash might appear as soon as one day after being exposed, Madsen says.
How to treat poison sumac
Poison sumac rash will generally fade on its own over time, but the symptoms can be extremely uncomfortable. There are several at-home remedies you can use to control itching and pain and your doctor can offer treatments for more severe cases.
1. Wash with soap and water
If you think you've come into contact with poison sumac, the first step you should take is to wash the area with soap and water. This can help limit the severity of the rash by removing any oil that's still on your skin, Madsen says.
"However, once you've been exposed, washing with soap and water likely won't completely prevent a reaction," says Madsen.
2. Try calamine lotion
If your poison sumac symptoms are mild, you can try gently rubbing over-the-counter calamine lotion on your skin.
Calamine lotion creates a cooling sensation as it evaporates off your skin, which can calm the itching. It can also help dry up any fluid that leaks from blisters on your rash.
3. Use hydrocortisone cream
Hydrocortisone cream is an anti-inflammatory steroid cream that can help reduce poison sumac symptoms like redness, swelling, and itching on your skin.
You can find hydrocortisone cream over the counter, but "if this isn't working, a prescription steroid cream may be more effective for treating these symptoms," Madsen says.
More severe cases of poison sumac rash may need a higher concentration of the steroid to control your symptoms.
4. Take an oatmeal bath
"Lukewarm baths can be great for symptom relief for any type of itching, and oatmeal baths in particular have been recommended for rashes and itching," Madsen says.
Oatmeal contains compounds that bind to your skin and create a protective barrier against any irritants. It's best to use colloidal oatmeal, which is a powder made from ground oats.
To make an oatmeal bath, follow these steps:
- Fill your bathtub with lukewarm water.
- Sprinkle one cup of colloidal oatmeal powder into the bathwater.
- Soak in the bath for 15 minutes.
- Get out of the bath and quickly pat your skin dry.
- Use a gentle moisturizer like Cetaphil.
5. Use a cool compress
A cool compress can help calm inflamed skin and reduce itching from a sumac rash.
To make a cool compress, soak a clean washcloth in cold water and then wring it out so it doesn't drip. Then lay the compress on your skin over any affected areas. You should remake the compress whenever it stops feeling cool.
You can also use ice wrapped in a towel, but putting ice directly on your skin can make irritation worse.
It works best to use a cool compress on your rash for 15 to 30 minutes at a time, several times per day, Madsen says.
6. Take an antihistamine
Typically over-the-counter antihistamines help reduce common allergy symptoms like sneezing, itching, and cough. But they can work for poison sumac in a pinch.
"Antihistamine medications don't seem to work as well for this type of rash as they might for other types of itching, but I still recommend that patients try these for some symptom relief," Madsen says.
If antihistamines aren't helpful, you can try other remedies or reach out to your doctor for another treatment option.
When to see a doctor
If poison sumac symptoms are getting worse or haven't cleared up after seven to ten days, you should contact your doctor.
"It's worth trying some over-the-counter treatments, but don't hesitate to talk with your doctor if you're not able to control the symptoms well at home," Madsen says.
For example, if your rash spreads to your eyes, mouth, or genitals you should see a doctor immediately.
You should also contact your doctor if you have any signs of infection, including:
- Puss coming out of your rash
- Yellow scabs
- Red streaks on your skin
- A fever over 100 degrees Fahrenheit
Insider's takeaway
Poison sumac can cause an itchy and uncomfortable rash but there are several ways you can relieve your symptoms. Using at-home treatments like calamine lotion and cool compresses is often helpful for poison sumac rash, but in more severe cases, you may need to contact your doctor for treatment.
If your symptoms are severe or aren't getting better with treatment, or if you have signs of infection, seek medical attention as soon as possible.