Critical care for frostbite.

Frostbite, a preventable cold-weather injury, occurs when the skin temperature cools to below 0°C with the formation of extracellular ice crystals. On rewarming, an inflammatory response develops, contributing to ischemia and tissue loss. The severity of injury depends on the temperature, duration of exposure, and amount and depth of frozen tissue. Environmental, individual, behavioral, and physiologic factors increase susceptibility to cold. Rapid rewarming and watchful waiting remains the mainstay of treatment. Prevention can be accomplished through increasing public awareness of the adverse effects of cold exposure, and recognizing and mitigating the risks associated with the development of frostbite.