Streaks of blisters. Poison ivy, oak, and sumac are plants that contain an oil (urushiol) which can cause a rash called allergic contact dermatitis when they touch your skin. The rash appears as itchy blisters (fluid filled bumps) or hives distributed classically in lines or streaks where the plant brushed against the skin. The rash usually appears 1-2 days from contact, but can occur up to 2 weeks after exposure.
Fluid filled bumps. A poison ivy rash usually looks like collections of fluid filled bumps or vesicles or "blisters" with some redness and streaks of rash along affected areas. Affected areas can include the feet, legs, hands, and arms or really anywhere that exposure has occurred. The rash is usually delayed a couple of days after exposure.