In cold temperatures, frostbite can set in quickly. Here are the causes, symptoms and treatment of frostbite.
Frostbite, known medically as congelatio, is the condition of skin or tissue damage due to exposure to cold. Frostbite usually affects the parts of the body furthest from the heart, such as the feet, hands, nose and ears.
The earliest evidence of frostbite was discovered in a 5,000-year-old pre-Columbian mummy found in the mountains of Chile. Frostbite was also a common affliction of soldiers. During the Yukon and Alaskan gold rush, miners and others unaccustomed to the extreme cold were particularly susceptible to frostbite.
Classification of Frostbite
Frostbite may be classified in one of three ways:
- Frostnip: the cooling of tissues without cell destruction; often an early stage of frostbite
- Chilblains (perniosis): superficial skin ulcers, due to repeated exposure to cold
- Frostbite: deep tissue destruction
A frostbitten person may also suffer hypothermia, in which the core body temperature drops below 35°C (95°F).
Cause of Frostbite
Frostbite can happen to anyone, although some people are more resistant. At a outside temperature of 0° Celsius (32°F), blood vessels near the skin begin to constrict. Blood flows away from the extremities as the body tries to preserve its core temperature.
Blood flow to affected parts of the body becomes minimal, causing skin tissue to freeze and die.
Causes of frostbite include:
- extreme environmental cold
- wind chill; exposure to high winds
- inadequate or wet clothing
- cramped conditions or low activity level in cold
- exposure to liquid nitrogen or other cryogenic liquids
Cryogenic liquids such as nitrogen or helium (which becomes liquid at extremely low temperature) can freeze the skin on contact.
Frostbite Risk Factors
Certain factors may predispose a person to frostbite. These include:
- medication such as beta blockers
- peripheral neuropathy (nerve damage)
- poor circulation
Pets can also get frostbite. In animals such as cats and dogs, the ears, tail and paws are especially vulnerable. See: Frostbite in Cats: Symptoms and Treatment.
Symptoms of Frostbite
Frostbite symptoms include pain, which varies depending on the degree of frostbite.
The Four Degrees of Frostbite
First Degree: Frostnip
Frostnip occurs when the skin freezes, but no permanent damage results. Initially, frostnip causes itching, tingling and pain. Later, patches of red, yellow or white develop on the skin. Frostnip may cause long-term sensitivity to heat or cold.
Second Degree: Blisters
As frostnip worsens, the skin freezes and becomes hard. The deep tissues are not yet affected. Blisters develop one to two days after exposure. Blisters may blacken and harden, and can appear more serious than they are. The second degree of frostbite usually heals in about a month. The area may permanently lose sensitivity to heat or cold.