Poison Ivy, Poison Oak and Poison Sumac

The warm weather lures us to take long nature walks or to work in our neglected gardens. However harmless these events may seem, certain green leaved hazards are waiting to share their toxin with a simple brush of the skin. The resulting rash is called contact dermatitis and poison ivy, poison oak and poison sumac are the culprits.

Poison ivy can be a shrub or vine and is found in the Midwest and East. It grows with three leave clusters on a main stem and has yellow to green flowers with white berries. An easy mnemonic to remember is, “Leaves of three, let them be.” Poison oak can be found as a vine or shrub and it also grows three-leaf clusters but they are similar to oak leaves. They also produce yellow berries. Poison sumac is a shrub that can become 15 feet tall with seven to 13 leaves and pale yellow berries on each main stem. It grows in boggy areas, especially in the Southeast.

These plants contain urushiol which is a clear oil found in the leaves, root, stem, fruit and sap. Urushiol can be transferred to you by direct contact to a damaged plant’s sap or indirect contact with an item that has urushiol on it, such as animal fur or gardening tools. Airborne contact can also occur when the plants are burned. Urushiol can also remain potent on inanimate objects for years, depending on the environment.

Approximately 50 to 70 percent of individuals exposed to urushiol will develop contact dermatitis. The initial symptoms include intense itching, redness and swelling of the affected skin which occur within hours to days of exposure. Later blisters may develop in a linear fashion consistent with the contact of the plant. The extent of the reaction depends on the location of the body involved. The face and genitals will have a much more severe response than the thick skin of the hands or feet. Exposed areas should be washed immediately with plain water and clothes laundered.

Symptoms typically resolve within one to three weeks without treatment. However, oral antihistamines, topical steroids and preparations like calamine lotion can help control the itching. Sometimes a prescription strength topical steroid may be required but these should not be used on the face, genitals or skin folds. An oral steroid taper lasting two to three weeks may also be prescribed for more severe cases. It should be noted that topical antihistamines, preparations with benzocaine or topical antibiotics with neomycin or bacitracin should not be used, because the rash could become worse.

Sometimes the blisters may rupture and become infected with increased redness, pain or discharge. It is important if there are any of these signs that a healthcare provider be consulted immediately, as treatment with antibiotics will be required. Medical care should also be sought if you have a fever, the rash worsens or involves the face or genitals, or if the rash covers a large portion of your body.

Prevention is imperative, which includes wearing protective clothing and thick vinyl gloves (urushiol can penetrate rubber and latex), washing yourself and pets immediately after exposure, laundering clothing and avoiding burning the poisonous plants. Keeping these things in mind will help you avoid a very unpleasant experience.