what causes poison ivy to itch?
Poison ivy, oak, and sumac are plants that can cause a red, itchy rash called allergic contact dermatitis . It is the most common skin problem caused by contact with plants. The rash is caused by contact with a sticky oil called urushiol (say yoo-ROO-shee-all) found in poison ivy, oak, or sumac. You can get the rash from: Touching or brushing against any part of these plants, including the leaves, stems, flowers, berries, and roots, even if the plant is dead.
1 Poison ivy, poison oak, and poison sumac are plants than can cause an itchy rash upon contact. 2  A substance called urushiol, found in these plants, causes the rash. 3  The rash is not contagious. 4  The rash usually disappears in one to three weeks.  The majority of cases can be treated at home.