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Summertime Rashes: Poison Ivy, Oak, and Sumac
Coming into contact with poison ivy, oak, or sumac can really put a damper on your summertime fun. People who are allergic to these plants can develop an extremely itchy, red skin rash with bumps and blisters. The oil from the poisonous plants is called urushiol and it adheres to whatever it touches (like skin, clothing, or pet hair) making it a nuisance even after you have left the plant far behind.
The rash is called contact dermatitis—an inflammatory response of the skin that occurs when it has come in contact with an allergen (a substance that may induce an allergic reaction). In the United States, contact with poison ivy, oak, and sumac are the most common cause of contact dermatitis. All are treatable, but sometimes extreme reactions occur. Call emergency medical services or go to an emergency room if you have trouble breathing or swallowing after exposure to these plants.
Ideally, the best step is to prevent any problems (mild or severe) from occurring in the first place. Before you head to the woods or sand dunes this summer, learn about this irritating trio of poisonous plants.
Preventing the Rash
If you think you have been exposed, you have a short window of opportunity to prevent a rash from breaking out. It takes about 10 minutes for urushiol to seep into the skin. As soon as you realize that you may have come in contact with one of these plants, thoroughly wash the area with soap and water.
Anything that comes in contact with the urushiol has to be washed off to prevent repeat exposure. If you have come in contact or think you have come in contact with these plants wash all clothes in a washing machine. Urushiol can stay on clothes for a very long time if unwashed.
If you have a pet that came in contact with the plants, get them into a bath or shower and scrub with pet soap. If you can, make sure you wear disposable gloves so you do not get exposed to the urushiol. It is not likely your pet will be affected, but you can develop a rash if you touch your pet's fur.
You may want to remove the plants that exist near your home. Make sure to wear gloves while doing gardening work. Wash or dispose the gloves when you're done. Do not burn the plants. Smoke from the plants can be inhaled and cause shortness of breath and itchy, watery eyes.
Remember, you have a short window of time to take action. If you miss that window, there are ways to treat that itchy rash.
Treating the Rash
If the rash has set in, the main goals of treatment are to stop the itching, decrease inflammation, and prevent infection.
Itching can make you very uncomfortable, but it may also encourage scratching the area. Constant scratching may lead to an infection through breaks in the skin. Once you have an infection, it will make the healing process longer. Be on the lookout for infection. Signs of infection include increased redness, tenderness, and/or swelling in the affected area, whitish or yellowish (rather than clear) fluid oozing from the blisters, and an odor. If you suspect infection, call your doctor right away.
Treatment for Mild Reactions
Most of the time, reaction is mild with the rash covering a small portion of your body. Most likely, you can treat yourself at home with:
- Cool compresses—to decrease relieve itching
- Calamine lotion—to dry out the affected area and alleviate itching
- Baths with oatmeal—to ease the itch
Treatment for More Severe Reactions
If you have a more severe outbreak that has blisters, or the rash covers a larger area of your body, see a doctor. You may need additional treatment that includes prescription medication such as:
- Oral antihistamines—to lessen the itching
- Topical corticosteroid cream or ointment—to reduce inflammation and itching
- Oral corticosteroids—to treat severe cases that involve a large area, the face, around the eyes, or the genitals
If you have it now or had it before, take some time to learn about these poisonous plant so you can stay rash-free in the future.
Keep away from any shrubs or vines with leaves of 3. These may be either poison ivy or poison oak. Poison sumac is a leaf of 5. All 3 plants also grow berries in the early fall.
Here are some other ways you can protect yourself:
- Learn what the plants look like, and avoid all contact with them.
- When you are in wooded areas, wear long pants and sleeves. Consider gloves if working with your hands.
- Use a topical product that contains quaternium-18 bentonite. It is an over-the-counter medication that can prevent a rash if applied at least 15 minutes before exposure. (IvyBlock, for example).
- If your clothes or gloves come in contact with poison ivy, oak, or sumac, try not to touch them. Throw them away or wash them in soap and water as soon as possible. If you have to handle your clothes, immediately wash your hands so you do not get poison ivy from your clothes.
Know what you are getting into ahead of time if at all possible and take the necessary precautions. It will help you keep the poison away and enjoy the outdoors.
American Academy of Dermatology
Family Doctor—American Academy of Family Physicians
Canadian Dermatology Association
The College of Family Physicians of Canada
Allergic contact dermatitis. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated April 28, 2014. Accessed November 5, 2014.
Outsmarting poison ivy and other poisonous plant. US Federal Drug Administration website. Available at: http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm049342.htm. Updated October 14, 2014. Accessed November 5, 2014.
Poison ivy, oak, and sumac. American Academy of Dermatology website. Available at: https://www.aad.org/dermatology-a-to-z/diseases-and-treatments/m---p/poison-ivy. Accessed November 5, 2014.
Usatine RP, Riojas M. Diagnosis and management of contact dermatitis. Am Fam Physician. 2010;82(3):249-255.
- Reviewer: Michael Woods, MD
- Review Date: 11/2014
- Update Date: 11/05/2014