The skin is the body's largest organ. It serves many important functions, including regulating body temperature, maintaining water and electrolyte balance, and sensing painful and pleasant stimuli. The skin keeps vital chemicals and nutrients in the body while providing a barrier against dangerous substances from entering the body and provides a shield from the harmful effects of ultraviolet radiation emitted by the sun. In addition, skin color, texture, and folds help mark people as individuals. Anything that interferes with skin function or causes changes in appearance can have important consequences for physical and mental health.

Last full review/revision October 2006 by Robert J. MacNeal, MD