frostbite

frostbite (chilblains), injury to the tissue caused by exposure to cold, usually affecting the extremities of the body, such as the hands, feet, ears, or nose. Extreme cold causes the small blood vessels in the extremities to constrict. The blood circulates more slowly and stagnation results. Eventually the body fluids may freeze. The condition is aggravated by tight clothing, physical inactivity, and dampness. Severe frostbite that is not treated may result in gangrene; amputation of the affected part may be necessary. See first aid .

frostbite Freezing of living body-tissue in sub-zero temperatures. Frostbite is an effect of the body's defensive response to intense cold, which is to shut down blood vessels at the extremities in order to preserve warmth at the core of the body. Consequently, it mostly occurs in the face, ears, hands, and feet. In superficial frostbite, the affected part turns white and cold; it can be treated by gentle thawing. In deep frostbite, ice crystals form in the tissues. The flesh hardens and sensation is lost. It requires urgent medical treatment. No attempt should be made at rewarming if there is a risk of refreezing, as this results in the death of body tissue (gangrene).

frostbite (frost-byt) n. damage to the tissues caused by freezing. The affected parts, usually the nose, fingers, or toes, become pale and numb. Ice crystals form in the tissues, which may thus be destroyed, and amputation may become necessary. Frostbitten skin is highly susceptible to bacterial infection.