Poison ivy, poison oak, and poison sumac are plants that have a sticky oil that can cause
an itchy, red rash. The rash often shows up in lines or streaks along with blisters or large raised areas (hives). In some people, it causes serious symptoms such as swelling and
widespread, large, oozing blisters.
Home treatment will often relieve mild symptoms.
Prescription medicine may be needed for severe reactions.