Poison Ivy rash is caused by an allergic reaction to urushiol, an oily resin found in the roots, stems, and leaves of Poison Ivy, Poison Oak, and Poison Sumac plants. The symptoms are red, itchy, potentially painful blisters and swelling that can form as soon as four hours after contact or up to two days later. The amount of exposure to urushiol and the sensitivity to it determine the severity of the rash, and reactions take two to three weeks to clear without treatment.

Because the substance is extremely sticky, a person can not only get it by touching the plant itself, but by touching something that has come into contact with the plant as well, like a pet, garden tools, or clothing. It will remain on the skin or other items until washed off, so it is important to clean the body and anything that may be affected a soon as possible. At home treatments that may help soothe the skin and bring some comfort are: using an over-the-counter cortisone cream (for the first few days), soaking in a cool bath with either baking soda or an oatmeal-based bath product, applying cool, wet compresses several times a day, applying calamine lotion or creams containing menthol, and taking an oral antihistamine.

Complications can occur when scratching causes blisters to open and become infected by bacteria. If pus is oozing from the blisters, an antibiotic maybe necessary. Call the doctor if this happens or if you have a fever over 100, trouble breathing, the rash is located in the mouth, eyes, or genitals, covers a large area of skin, or does not seem to be improving at all after one week. The doctor may prescribe an oral corticosteroid (like prednisone) to decrease swelling or give you a steroid cream to apply to the area.