some people develop black spots or streaks instead of a reddish rash. "Poison ivy is not contagious. However, the part of poison ivy that causes allergic reactions [aka urushiol] can be spread on ...

In black-spot poison ivy dermatitis, a black lacquerlike substance forms on the skin when poison ivy resin is exposed to air. Although the Toxicodendron group of plants is estimated to be the most ...

there might be a visible black substance, called urushiol, on the leaves or stems. This is the same compound found in other poisonous plants like poison ivy and is responsible for causing a rash ...

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.

This member of the Anacardaceae family, which also includes poison oak and poison sumac, contains an oil resin that causes a horribly itchy and bumpy rash ... spot-treat or paint the poison ivy ...