Blister

A blister is a defense mechanism of the human body. It consists of a pool of lymph and other bodily fluids beneath the upper layers of the skin. It may be formed in response to burns or friction, and helps to repair damage to the skin. If a blister is punctured, it forms an open wound and must be bandaged.

Certain autoimmune diseases feature extensive blistering. These include pemphigus and pemphigoid. Blistering also occurs as part of foodborne illness with Vibrio vulnificus (seafood).