The scourge of summertime yard workers, campers, and hikers is upon us. Poison ivy, oak, and sumac are all present in East Texas. They typically grow in vines with poison ivy usually having three leaves per stem, thus the old adage “Leaves of three, let it be.” They are called “poison” because of the chemical urushiol which can be found on the leaves, stems, and roots. A person usually has to come in direct contact with the plant; however, the oil may be transmitted by fomites (such as tools or pets that you then contact) or even in the smoke of a burning brush pile.

Poison ivy causes what we call a contact dermatitis - a reactive, inflammatory skin disorder. This is a type of allergic reaction to urushiol, which explains why some people may get it much worse than others. (Countless other plants and chemicals can cause a contact dermatitis.) The rash is variable. A classic case causes small blisters on a red base often arranged in lines, but other presentations may include large blisters or just red bumps. It usually itches intensely. People get the impression that the rash is “spreading” since it may break out in different places over time; however, this is actually due to the fact that different areas of skin have different sensitivities and may take longer to react. It is not contagious.

Treatment usually involves steroids due to their anti-inflammatory properties. Small areas can be treated with creams but larger areas require systemic treatment, either pills, an injection, or both. Calamine and other similar lotions may have some soothing effect for the skin, but we think their role is limited. Benadryl or stronger antihistamines may be prescribed for severe itching. The best advice is avoidance: wear long sleeves, long pants, and gloves when dealing with thick foliage and unknown vines.