Poison Oak Rash on the Arm

Poison oak rash on the arm. Several plants produce toxins that cause skin reaction. This is the appearance of poison oak dermatitis. Note the typical linear streaks produced either by scratching or brushing against the plant. (Courtesy of the Centers for Disease Control.)

Poison Ivy on the Knee

This is a typical early appearance of a poison ivy rash, located on the knee. These early lesions consist of multiple small blisters (vesicles), often in a line where the skin has brushed against the poison ivy plant. The person may then spread the toxin to other areas of the body by scratching.

Poison Ivy on the Leg

This is a typical early appearance of a poison ivy rash, located on the leg. These early lesions consist of multiple small blisters (vesicles), often in a line where the skin has brushed against the poison ivy plant. The person may then spread the toxin to other areas of the body by scratching.

Rash

A rash is an eruption of changes in color or texture of the skin.