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, poison oak, and poison sumac are the most common cause of contact dermatitis. Poison ivy, oak, and sumac are treatable. Some can have extreme reactions. Contact 911 and get 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 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 you have a pet that came in contact with the plants, get him 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 are 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 about 10 minutes to take action. You may miss your chance. If you do here are some ways to treat that itchy rash.

Treating the Rash

Once the rash has set in, the three 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 a funny 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 large 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.

Protecting Yourself

Follow the rule of three: keep away from any shrubs or vines with leaves of three. These may be either poison ivy or poison oak (poison sumac is a leaf of 5). All three 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.

• Reviewer: Brian Randall, MD
• Review Date: 11/2012 -
• Update Date: 11/29/2012 -