What is poison ivy, oak and sumac?

Poison ivy, poison oak, and poison sumac are plants that can cause a skin rash upon contact. The red, itchy rash often shows up in lines or streaks. It may cause fluid-filled blisters or large, raised hives.

The rash is caused by an allergic reaction to an oil in these plants. The rash may occur when you touch the plant or when you touch objects that have come in contact with these plants. Common examples include clothing, pet fur, sporting gear, or gardening tools.

You can't catch or spread the rash by touching the rash or the blister fluid. The plant oil will already have been absorbed or washed off the skin. The rash may seem to be spreading because it's still developing from earlier contact or because you have touched something that still has the plant oil on it.

The usual symptoms are itching, redness where the plant touched the skin, small bumps or hives, and blisters that may leak fluid. People who are very allergic to the oil may have serious symptoms, such as trouble breathing, swelling of the face, mouth, neck, or genitals, and widespread, large blisters that ooze fluid.

Mild to moderate rash

If you get a mild rash, you can take care of it at home. Here are some tips to help with itching:

• Apply a cool, wet cloth for 15 to 30 minutes several times a day.
• Take short, cool baths.
• Use calamine lotion to help relieve itching.
• Try not to scratch the rash. Scratching could cause a skin infection.

If itching affects your sleep, ask your doctor if you can take an antihistamine that might reduce itching and make you sleepy, such as diphenhydramine (Benadryl). Be safe with medicines. Read and follow all instructions on the label.

Severe rash

See your doctor if:

• The rash covers a large area of your body.
• Your symptoms are severe.

Your doctor may treat your rash with prescription corticosteroid pills, creams, or shots.

If you think you have touched any of these plants:

• Wash your skin right away with plenty of water. If you can, use liquid dish soap or a mild soap and very warm running water.
• Use a brush to clean under your nails.
• Wash any clothing or other items that might have the oil on them. Do it right away.

The best way to prevent future rashes is to learn to identify these plants and avoid them.

When you can't avoid contact with the plants:

• Wear long pants, long sleeves, and closed shoes to help keep the oil from getting on your skin.
• Wear vinyl or leather gloves. Rubber (latex), cotton, or wool gloves offer no protection.
• Use a barrier cream or lotion, such as Ivy X Pre-Contact Skin Solution. It can help keep the oil from coming in contact with your skin.
• If you did not use a preventive product and you have had contact with plant oil, clean it off your skin with an after-contact product as soon as possible. These products, such as Tecnu Original Outdoor Skin Cleanser, can also be used to clean plant oil from clothing or tools.

Experts say not to burn plants like poison ivy, oak, or sumac. When these plants burn, urushiol attaches to smoke particles. Exposure to the smoke can cause a rash on your skin. Breathing in the smoke can also hurt your lungs.

A doctor can usually diagnose the rash by looking at it. The doctor will ask when you were exposed to the plant and how long it took the rash to develop. You'll also be asked about your outdoor activities, work, and hobbies and about other rashes you've had.

• If your doctor prescribed a cream, use it as directed. If the doctor prescribed medicine, give it exactly as prescribed. Call your doctor if you think your child is having a problem with a medicine.
• Use cold, wet cloths to reduce itching.
• Take warm or cool baths with oatmeal bath products, such as Aveeno.
• Keep your child cool and out of the sun.
• Leave the rash open to the air.
• Wash all clothing or other things that may have come in contact with the plant oil.
• Avoid most lotions and ointments until the rash heals. Calamine lotion may help relieve symptoms of a plant rash. Use it 3 or 4 times a day.

To prevent exposure

• If you know that your child might go near poison ivy, oak, or sumac when playing outdoors, use a product (such as Ivy X Pre-Contact Skin Solution) that helps prevent plant oil from getting on the skin. These products come in lotions, sprays, or towelettes. You put the product on the skin right before your child goes outdoors.
• If you did not use a preventive product and your child has had contact with plant oil, clean it off your child's skin with an after-contact product as soon as possible. These products, such as Tecnu Original Outdoor Skin Cleanser, can also be used to clean plant oil from clothing or tools.

Poison ivy, oak, and sumac are plants that can cause a red, itchy rash called allergic contact dermatitis. It is the most common skin problem caused by contact with plants.

The rash is caused by contact with a sticky oil called urushiol (say "yoo-ROO-shee-all") found in poison ivy, oak, or sumac. You can get the rash from:

• Touching or brushing against any part of these plants (including the leaves, stems, flowers, berries, or roots), even if the plant is dead.
• Touching anything that's come in contact with these plants, like clothing, sporting gear, gardening tools, or pet fur.
• Exposure to smoke from burning these plants. Urushiol attaches to smoke particles and can cause a rash on any part of the body.

The rash is an allergic reaction to the oil. You become allergic through contact. After you've come in contact with these plants, your immune system may start to react to the oil as though it's a harmful substance.

The rash is only spread through the oil. You can't catch a rash by touching the blister fluid.