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Poison ivy rash Overview
Poison ivy rash is caused by an allergic reaction to an oily resin called urushiol (u-ROO-she-ol). This oil is in the leaves, stems and roots of poison ivy, poison oak and poison sumac.
Wash your skin right away if you come into contact with this oil, unless you know you’re not sensitive to it. Washing off the oil may reduce your chances of getting a poison ivy rash. If you develop a rash, it can be very itchy and last for weeks.
You can treat mild cases of poison ivy rash at home with soothing lotions and cool baths. You may need prescription medication for a rash that’s severe or widespread especially if it’s on your face or genitals.
Poison ivy rash is caused by a sensitivity to an oily resin called urushiol (u-ROO-she-ol), which is found in the leaves, stems and roots of poison ivy, poison oak and poison sumac.
At least 50 percent of the people who come into contact with these plants develop an itchy rash. The most dangerous type of exposure occurs when the plant is burned and the smoke is inhaled, which can affect your lungs.
Mild cases of poison ivyrash require no medical treatment. For more severe or widespread rashes especially if it’s on your face or genitals your doctor may suggest taking corticosteroid pills, such as prednisone, for a few weeks.
Symptoms of Poison ivy rash
Signs and symptoms of a poison ivyrash include:
- Redness
- Itching
- Swelling
- Blisters
Often, the rash looks like a straight line because of the way the plant brushes against the skin. But if you come into contact with a piece of clothing or pet fur that has urushiol on it, the rash may be more spread out. The reaction usually develops 12 to 48 hours after exposure and typically lasts two or three weeks.
The severity of the rash depends on the amount of urushiol that gets on your skin. A section of skin with more urushiol on it may develop a rash sooner. You can also transfer the oil to other parts of your body with your fingers.
Your skin must come in direct contact with the plant’s oil to be affected. Blister fluid doesn’t spread the rash.
Causes of Poison ivy rash
Poison ivyrash is caused by an oily resin called urushiol found in the leaves, stems and roots of poison ivy, poison oak and poison sumac. Urushiol is very sticky, so it easily attaches to your skin, clothing, tools, equipment or pet’s fur.
You can get a poison ivy reaction from:
- Direct touch. If you directly touch the leaves, stem, roots or berries of the plant, you may have a reaction.
- Touching contaminated objects. If you walk through some poison ivy and then later touch your shoes, you may get some urushiol on your hands, which you may then transfer to your face by touching or rubbing. If the contaminated object isn’t cleaned, the urushiol on it can still cause a skin reaction years later.
- Inhaling smoke from the burning plants. Even the smoke from burning poison ivy, poison oak and poison sumac contains the oil and can irritate or harm your nasal passages or lungs.
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.
Outcome
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. You will find dermatologists’ tips for treating the rash and relieving the itch as your skin heals at Poison ivy: Tips for treating and preventing.
