Despite their names, poison ivy, poison oak and poison sumac aren’t really poisonous. The burning, itching skin rash that results when skin comes in contact with these plants is caused by an oil called urushiol. When bare skin touches these plants, or when the oil is transferred to the skin from contaminated objects like clothing, tools or even pets, the substance quickly enters the skin. Within 24-72 hours, itching, red bumps and oozing blisters can appear, persisting for one to three weeks.
Contrary to conventional wisdom, poison oak and poison ivy are not spread through the fluid that oozes from the blisters. Instead, any delayed skin reactions likely are caused by further contact with clothing or other objects contaminated with the oil.
You can remove the oil from the skin with gentle, extended washing with soap and water, preferably within 30 minutes of contact. Use a dish detergent, which binds effectively with the oil. Gently scrubbing the fingernails with a soft brush can help prevent spreading the oil to other parts of the body.
Calamine lotion or hydrocortisone cream can lessen itching and rash. However, see your doctor if severe blistering, swelling or itching occur; if the rash appears around the eyes, lips or genitals, or over a large area of the body; or if the blisters become infected and ooze pus.
Wash clothing and shoes with soap and hot water, and clean contaminated items with rubbing alcohol or a diluted bleach solution. Wash pets with pet shampoo and lukewarm water, if they have been in contact with one of these plants.
To avoid contact with the leaves of poison ivy, poison oak and poison sumac, wear long sleeves, long pants, gloves and socks when you’re in bushy or overgrown areas where these plants may grow. Wash your clothing and shoes after returning, and keep pets away from these areas.