PhillyHealthInfo.org
The College of Physicians of Philadelphia


Fight the Itch!

First comes the itching, then a red rash, and then blisters. These symptoms of poison ivy, poison oak, and poison sumac can start from a few hours to several days after exposure to the plant oil found in the sap of these poisonous plants.

Recognizing Poison Ivy, Poison Oak, and Poison Sumac

imagePoison Ivy: Found throughout the United States except Alaska, Hawaii, and parts of the West Coast. Can grow as a vine or shrub. Each leaf has three glossy leaflets, with smooth or toothed edges. Leaves are reddish in spring, green in summer, and yellow, orange, or red in fall. May have white berries.




imagePoison Oak: Grows as a low shrub in the eastern United States, and in tall clumps or long vines on Pacific Coast. Fuzzy green leaves in clusters of three are lobed or deeply toothed with rounded tips. May have yellow-white berries.




imagePoison Sumac: Grows as a tall shrub or small tree in bogs or swamps in Northeast, Midwest, and parts of the Southeast. Each leaf has clusters of seven to 13 smooth-edged leaflets. Leaves are orange in spring, green in summer, and yellow, orange, or red in fall. May have yellow-white berries.




Not Contagious
Poison ivy and other poison plant rashes can’t be spread from person to person. But it is possible to pick up the rash from plant oil that may have stuck to clothing, pets, garden tools, and other items that have come in contact with these plants. The plant oil lingers (sometimes for years) on virtually any surface until it’s washed off with water or rubbing alcohol.

The rash will only occur where the plant oil has touched the skin, so a person with poison ivy can’t spread it on the body by scratching. It may seem like the rash is spreading if it appears over time instead of all at once. But this is either because the plant oil is absorbed at different rates in different parts of the body or because of repeated exposure to contaminated objects or plant oil trapped under the fingernails. Even if blisters break, the fluid in the blisters is not plant oil and cannot further spread the rash.

Tips for Prevention

Tips for Treatment
Don’t scratch the blisters. Bacteria from under your fingernails can get into the blisters and cause an infection. The rash, blisters, and itch normally disappear in several weeks without any treatment. But you can relieve the itch by:

See a Doctor

This information provided by the US Food and Drug Administration.