Bullous pemphigoid is a blistering skin condition that most often affects the elderly. This is a close-up picture of the typical blisters. Large blisters, like these, are called bullae.

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.

This is a typical early appearance of a poison ivy rash, located on the leg. These early lesions consist of multiple small blisters, often in a line where the skin has brushed against the poison ivy plant. The rash is caused by skin contact with the oily sap (resin) of these plants. The oily resin usually enters the skin rapidly, and is seldom transferred from person to person. The rash is not caused by the fluid from the blisters. Thus, once the person has washed the oil off the skin, the rash is usually not contagious.