Poison oak rash is an allergic reaction to the leaves ... depending on the time of year. Like poison ivy and poison sumac, poison oak releases an oil called urushiol when it sustains damage.

A poison ivy rash will last at least a week and likely more if you've never been exposed before. If you come into contact with poison ivy, the rash will typically appear within 12-48 hours.

Poison ivy, poison oak, and poison sumac are three plants notorious for causing itchy, uncomfortable rashes that can turn a pleasant outdoor experience into a nightmare. These plants contain ...

Poison sumac rash symptoms Poison sumac works the same way as poison ivy and poison oak — all three plants contain an oil called urushiol that causes an allergic reaction in most people.

Medically reviewed by Susan Bard, MDAn itchy rash with blisters can be caused by an allergic reaction; an autoimmune disorder ...