When outdoor temperatures drop to near or below freezing, frostbite can occur after exposure to cold conditions for an extended amount of time. Frostbite can involve damage to the skin, tissue, and even underlying nerves, muscles, tendons, and bones in more severe cases. The body reacts to exposure to cold by constricting its blood vessels, which restricts the flow of blood and oxygen, particularly in the feet, hands, ears, nose, and lips. A lack of circulation can lead to dead skin and tissue.

Frostbite most commonly affects the elderly and diabetics, as they have poorer circulation to these areas. Children are also more susceptible to frostbite because of their smaller extremities. Those who are exposed to cold temperatures for long periods of time, such as outdoor workers and the homeless, are at an increased risk for developing frostbite.

Superficial frostbite affects only the three layers of the skin and can penetrate to the third, or subcutaneous layer. Deep or advanced frostbite is a very serious condition, when the damage has spread to the nerves, muscles, tendons, and even bones. In this case, the skin may turn white, blue, or even black. The frostbitten areas may have gangrene, or dead tissue, which may need to be surgically removed to prevent infection. Although frostbite sufferers can fully recover, they may experience a lasting sensitivity to cold and be more prone to future cases of frostbite.

If frostbite strikes, immediately get medical help and find a warm environment. Rather than warming the skin with too hot of a source, such as sitting close to a portable heater or fireplace, gradually return the skin to a warmer temperature. Thawing the skin and then subjecting it to refreezing is particularly dangerous.

Frostbite can be prevented by avoiding prolonged exposure to freezing temperatures. If you will be outside in frigid temperatures, keep the feet warm and dry by wearing appropriate socks and boots. Go inside frequently to warm up, and be sure to remove any wet clothing, as wet skin is more prone to frostbite. Again, do not thaw and refreeze frostbitten skin.