Frostbite

Frostbite, injury to the skin and sometimes the deeper tissues of the body due to freezing or formation of ice crystals in the tissue cells. Frostbite usually develops when the air temperature is below -12° C (10° F), but may occur at a temperature nearer the freezing point (0° C/32° F) when other elements, such as high winds, dampness, or general chilling of the body, are present. The onset of frostbite causes little discomfort and may not be noticed by the victim because the cold has an anesthetic effect on the tissues.

Frostbite develops in three stages: a reddening of the skin, formation of blisters, and finally death of some of the skin cells and the underlying tissues. Clots often form in the blood vessels. Mild cases of frostbite often result in chilblain; more severe cases may result in a dangerous gangrene. Free circulation of the blood inhibits the onset of frostbite.

The parts of the body most often affected are the hands, feet (especially the heels and toes), ears, cheeks, chin, and nose. The recommended first-aid treatment for frostbite is the immediate application of warmth to the injured parts; if possible the affected areas should be soaked in warm water. Vigorous massage should be avoided because it would cause further harm to the damaged tissues.