Many people get a rash from poison ivy, poison oak, and poison sumac. This rash is caused by an oil found in the plants. This oil is called urushiol (you-ROO-shee-all). The itchy, blistering rash often does not start until 12 to 72 hours after you come into contact with the oil.
The rash is not contagious and does not spread. It might seem to spread, but this is a delayed reaction.
Most people see the rash go away in a few weeks. To make the skin feel more comfortable during this time, you’ll find tips from the American Academy of Dermatology here:
If you have a serious reaction, you need to see a doctor right away. Swelling is a sign of a serious reaction — especially swelling that makes an eye swell shut or your face to swell.
You should see a doctor if the rash covers a large part of your body, you have large blisters, or cannot sleep.
If you have trouble breathing or swallowing, go to an emergency room immediately.
What you see and feel on your skin is caused by urushiol (you-ROO-shee-all). Urushiol is the oil in poison ivy, oak, and sumac. You find this oil in all parts of the plants — the leaves, stems, and even the roots. Within minutes of contact with urushiol, the skin starts to absorb it. But you don't feel this. And you don't see a rash right way.
If this is your first contact with urushiol, you may not see a rash. Or it may take a week for the rash to appear. The rash also can appear within hours or a few days. If you have a reaction to the oil, you can have these signs (what you see) and symptoms (what you feel):
The rash is very itchy and can appear on any part of the body. The rash can continue to appear on new parts of the body when:
You cannot give the rash to someone else. Even if the person touches the rash or the fluids in the blisters, the person cannot get the rash. The person has to touch the oil to get the rash.
Who gets this rash?
Most people (85 percent) develop a rash when they get urushiol on their skin. The first time you get this oil on your skin, you may not get a rash. The next time this oil gets on your skin you can become sensitive to it. Once you are sensitive to it, a rash appears. About 15 percent of people do not become sensitive to this oil and never develop a rash.
Adults who had rashes as a child often find that they are less sensitive as adults. They may completely lose their sensitivity and never get another rash when the oil touches their skin. Adults who never had a rash as a child may become sensitive to the oil.
What causes this rash?
There are 3 ways to get this rash:
It is not possible to get this rash from touching someone who has the rash. The skin absorbs the oil too quickly. You cannot get a rash from getting the fluid in the blisters on your skin.
If you have any of the following symptoms, go to the emergency room right away:
How do dermatologists diagnose poison ivy?
A dermatologist can usually look at the rash and tell you whether your rash is due to poison ivy, oak, or sumac.
How do dermatologists treat poison ivy?
If you have a serious reaction, you will likely need prescription medicine. Your dermatologist may prescribe a steroid ointment that you can apply to the skin. To treat a severe case, a strong medicine like prednisone may be necessary.
If you have an infection, your dermatologist may prescribe an antibiotic. You likely have an infection if you develop a fever or have pus, pain, swelling, and warmth around the rash.
If you are not sure what caused your rash, you should see a dermatologist. Rashes appear on the skin for many reasons.
A rash from poison ivy, oak, or sumac usually lasts 1 to 3 weeks. Most rashes go away without treatment. While your skin heals, it often itches.
A rash from poison ivy, poison oak or poison sumac is caused by an oil found in these plants called urushiol (you-ROO-shee-all). When this oil touches your skin, it often causes an itchy, blistering rash.
Most people can safely treat the rash at home. However, if you experience any of the following symptoms, go to the emergency room right away.
To treat a rash from poison ivy, poison oak, or poison sumac and help stop the itch, dermatologists recommend the following:
If your rash is not improving after seven to 10 days, or you think your rash may be infected, see a board-certified dermatologist. A dermatologist can treat your rash and any infection and help relieve the itch.
Prevent a rash from poison ivy, oak, or sumac
There are two ways to prevent a rash:
Read the Poison ivy information at The American Academy of Dermatology to learn more about identifying these plants.
How to protect your skin from poison ivy, oak, and sumac
Sometimes you cannot avoid these plants. When you find yourself in this situation, there are some precautions you can take:
If you find yourself in an area with poison ivy, oak, or sumac, it helps to know the following:
If you get a rash from poison ivy, poison oak, or poison sumac, you can usually treat the rash at home. If you have a serious reaction, seek immediate medical care by going to the emergency room or calling 911.