Frostbite is damage to the skin and underlying tissues caused by extreme cold.

A person with frostbite on the extremities may also be subject to hypothermia (lowered body temperature). Check for hypothermia and treat those symptoms first.

Frostbite is distinguishable by the hard, pale, and cold quality of the skin that has been exposed to the cold for a length of time. The area is likely to lack sensitivity to touch, although there may be an aching pain. As the area thaws, the flesh becomes red and very painful.

Any part of the body may be affected by frostbite; but hands, feet, nose and ears are the most vulnerable. If only the skin and underlying tissues are damaged, recovery may be complete. However, if blood vessels are affected, the damage is permanent and gangrene can follow which may require amputation of the affected part.

Upon warming, it is common to experience intense pain and tingling or burning in the affected area.

Frostbite occurs when the skin and body tissues are exposed to cold temperature for a prolonged period of time. Hands, feet, noses, and ears are most likely to be affected.

Although anyone who is exposed to freezing cold for a prolonged period of time can get frostbite, people who are taking beta-blockers, which decrease the flow of blood to the skin, are particularly susceptible. So are people with peripheral vascular disease (a disorder of the arteries). Other things that may increase the risk of frostbite include: smoking, windy weather (which increases the rate of heat loss from skin), diabetes, peripheral neuropathy, and Raynaud's phenomenon.

The first symptoms are a "pins and needles" sensation followed by numbness. There may be an early throbbing or aching, but later on the affected part becomes insensate (feels like a "block of wood").

Frostbitten skin is hard, pale, cold, and has no feeling. When skin has thawed out, it becomes red and painful (early frostbite). With more severe frostbite, the skin may appear white and numb (tissue has started to freeze).

Very severe frostbite may cause blisters, gangrene (blackened, dead tissue), and damage to deep structures such as tendons, muscles, nerves, and bone.