Frostbite – freezing of skin and subcutaneous tissue – occur when a temperature that is much lower than a freezing point affect a part of the body (see Chilblains article for comparison). The blood flow to the affected area is interrupted and, in severe cases, the skin cells are permanently damaged.
Frostbite can affect any part of the body, but fingers, feet, nose and ears are in the greatest danger. Frozen skin is solid, pale, cold and painless. As the skin unfreezes, it becomes red and hurts. Anyone who is exposed to two hours (or longer) of great cold can be frozen, but the most sensitive are people with atherosclerosis or people treated with beta blockers.
To protect yourself from frostbite, wear a few layers of warm clothing underneath the unobtrusive cloak that protects you from the wind. Protect your ears, arms, and feet (and nose, if possible). Remember that exhaustion, alcohol and lack of oxygen at high altitudes may have a negative effect on your ability to reason, as you will not be mindful of the physical disturbances that alert you to the appearance of frostbite.
Frostbite should be treated immediately. Every minute of delay reduces the chances of healing. So, remember the instructions to overcome these problems before exposing yourself to cold conditions where there may be no medical help available.
If you do not recover completely after warming up, contact your doctor as soon as possible. There is a danger of dry gangrene that may require amputating the frozen part of the body. But, if you approach treatment quickly, frostbite usually has no effect.