Written by Dr. Ringpfeil

Poison Ivy

Overview

Poison ivy causes a skin irritation called contact dermatitis and results in a red, itchy rash consisting of small bumps, blisters or swelling. Many people are sensitive to an oily plant resin called urushiol, the common irritating substance in poison ivy, poison oak and poison sumac. It takes only a tiny amount of urushiol to cause a reaction. Urushiol is very sticky and doesn't dry, so it easily attaches to your skin, clothing, tools, equipment and pet's fur. Treatment for poison ivy aims to relieve the itching until the reaction naturally resolves.

Management

The poison ivy reaction is self-resolving and not contagious. However, certain circumstances require clinical attention. For example, a severe or widespread reaction; rash affecting sensitive areas of your body, such as your eyes, mouth or genitals; large blisters or a fever. Scratching a poison ivy rash with dirty fingernails might cause a secondary bacterial infection resulting in pus within the blisters. Treatment of a secondary infection generally requires prescription antibiotics. In rare circumstances, poison ivy may be so severe that hospitalization is indicated.

Treatment and Medication

The urushiol resin enters skin quickly, so try to wash it within 30 minutes of exposure with soap and water or with Tecnu, an oil-removing product. Scrub under the fingernails with a brush to prevent the resin from spreading to other parts of the body. Typically, the poison ivy rash goes away on its own within one to three weeks. Effective relief of symptoms can be achieved with over-the-counter medications like calamine lotion, hydrocortisone cream or aluminum acetate (Domeboro solution) soaks. Antihistamines can stop extreme itching. In severe cases, especially rash around the face or genitals, your doctor may prescribe oral or injected steroids.

Coping

Fortunately, neither the poison ivy rash nor blister fluid is contagious. Since the reaction is based on contact with urushiol, thoroughly clean anything that may be contaminated. If the contact with urushiol has left black stains on clothing or utensils, these need to be exposed off as effective cleansing can no longer be performed. Gently washing off the harmful resin from your skin within minutes after exposure may help avert a reaction.

Prevention

The best way to prevent an allergic or irritant reaction from urushiol is avoidance of contact with poison ivy, poison sumac or poison oak. Know what these plants look like and where they are commonly found. They typically have leaves made of three or more leaflets and climb on other plants or fences. When hiking or engaging in other activities that might expose you to poison ivy, try to stay on cleared pathways. Remove poison ivy from your backyard.