FROSTBITE

DEFINITION

Frostbite is damage to the skin and other tissue caused by freezing. The term frostnip is sometimes used for a mild form of frostbite.

DESCRIPTION

Frostbite is caused by exposure to temperatures well below freezing (32°F or 0°C). Dry conditions contribute to frostbite damage. At temperatures closer to freezing, frostnip is more likely to occur. Humid air is also more likely to produce frostnip than frostbite.

In North America, frostbite occurs most frequently in Alaska, Canada, and the northernmost regions of the United States. In recent years, the number of cases of frostbite and frostnip have decreased considerably. One reason for this change is that the general public is better educated about the dangers of these two conditions. Also, warmer clothing and footwear are generally available.

The one group of people among whom frostbite and frostnip has increased are the homeless. Homeless people often have no place to go when the temperature drops. The growing popularity of outdoor sports has also increased the number of people at risk for frostbite and frostnip.

CAUSES

The human body can withstand temperatures a little below freezing for hours before freezing. However, exposure to very cold temperatures can freeze skin in minutes or even seconds. Air temperature, wind speed, and moisture all affect the rate at which the body loses heat. For example, wet clothing increases the risk for frostbite. Water absorbs heat quickly and efficiently. It causes the body to cool off very quickly.

The permanent damage done to the body depends more on how long it was exposed to cold temperatures than on how cold it got. This fact explains why so many people are injured by frostbite. The overnight temperature may not drop very low, but homeless people are forced to remain outside for hours at a time. This long exposure to even mildly cold temperatures can cause frostbite.

Several factors increase a person's risk for frostbite. Alcohol use is a major risk factor for frostbite. Alcohol reduces blood circulation. It causes the body to cool off quickly. It also impairs ones judgement. A person who has been drinking may not notice how cold it is, or realize that he or she is getting frostbite, and stay outdoors even after injury has occured. In one study

Frostbite on fingers. (Photograph by

SIU

. Reproduced by permission of the

National Audubon Society Collection/Photo Researchers, Inc.

)

of frostbite injuries, nearly half occurred among people who had been drinking. Other factors contributing to the risk for frostbite include:

• Psychiatric illness
• Inadequate clothing
• Fatigue
• Infection from a wound
• Atherosclerosis (see atherosclerosis entry)
• Diabetes (see diabetes mellitus entry)
• Previous injuries due to cold temperatures

SYMPTOMS

Most frostbite injuries affect the feet or hands. About 10 percent of all cases involve the ears, nose, cheeks, or penis. The first symptoms of frostbite are a feeling of cold and numbness in the affected body part. The skin then begins to turn white or yellowish. Many patients experience severe pain in the affected part.

Symptoms continue as the body begins to warm up. The pain returns or continues during this period. It may last for days or weeks. As the skin begins to thaw, fluids may collect, causing swelling of the affected area. In more serious cases, deep, blood-filled blisters may form. In the most severe cases of frostbite, the muscles, tendons, nerves, and bones may also be damaged by cold. In such cases, dead tissue may drop off or become infected.

The symptoms of frostnip are less severe. The skin may turn pale. Numbness and tingling are likely to occur in the affected area.

DIAGNOSIS

A first diagnosis of frostbite or frostnip can usually be made on the basis of environmental conditions. A person found unconscious in freezing weather may be presumed to be at risk for frostbite. Physical examination of the skin often confirms this diagnosis. The skin tends to be cold, hard, white, and numb if frostbite is present. As it warms, the skin becomes red, swollen, and painful. Doctors usually classify the extent of frostbite as being superficial or deep. The prognosis for all forms of frostbite is often not clear for many days.

TREATMENT

Frostbite is a potentially serious problem that requires emergency medical treatment. First aid involves replacing wet clothing with warm, dry clothing or blankets. A splint or padding can be used to protect the injured area. Observers should not attempt to warm the patient in the field. The re-warming procedure should take place under controlled conditions in the hospital.

The outcome of a frostbite injury cannot be predicted in the first few days. For that reason, the same treatment is used with all patients. Treatment involves re-warming of the affected area at a temperature of 104° to 108°F (40° to 42°C). The injury is treated with aloe vera and splinted, wrapped, and elevated.

Injections of tetanus vaccine and penicillin may be given. These injections protect the patient against infection. An anti-inflammatory drug, such as aspirin or ibuprofen, may also be given. In some cases, narcotics may be needed to treat the severe pain that occurs with deep frostbite.

In the most serious cases, frostbite may cause extensive tissue damage. Amputation (removal) of an arm, leg, hand, or foot may be necessary. A decision to take this action is usually delayed as long as possible to see if the damaged tissue will recover.

Dr. Beck Weathers who suffered severe frostbite on his face and hands after being trapped in a blizzard on Mt. Everest. (Reproduced by permission of

AP/Wide World Photos

)

Alternative Treatment

Alternative treatments of frostbite should not be attempted until the patient has received medical care. After that point, methods are available for shortening the recovery period. One such method is contrast hydrotherapy. In contrast hydrotherapy, a series of hot and cold water applications is used on the affected area.

Some homeopathic remedies suggested for frostbite recovery include Hypericum and Arnica (pronounced AHR-nih-kuh). Circulation may be improved by drinking hot ginger tea or taking small amounts of cayenne pepper.

PROGNOSIS

A new approach to frostbite treatment was developed in the 1980s. The major emphasis in this method is to re-warm the body as quickly as possible. This method has proved to be very successful. In one study, about twothirds of patients with superficial frostbite recovered completely without tissue loss. The success rate using older methods was only about 35 percent (or about one-third of patients).

The most serious consequence of frostbite may be amputation. People who do not require amputation may still experience long-term symptoms. These symptoms include extreme throbbing pain, a burning sensation or tingling feelings, color changes of the skin, changes in the shape of nails or loss of nails, joint stiffness, excessive sweating, and a heightened sensitivity to cold.

PREVENTION

Frostbite typically occurs when a person is exposed to extreme weather conditions, such as very cold temperatures and high winds. Anyone who expects to encounter these conditions should prepare for them by dressing warmly and staying outside no longer than necessary. Outer garments should be wind- and water-resistant. If clothing becomes wet, it should be replaced as quickly as possible. Alcohol, drugs, and smoking should be avoided if one will be exposed to the elements for long periods of time.

Some groups of people, such as the homeless, may find it more difficult to avoid frostbite. They may not understand the need for protection from the cold or, more often, they do not have the resources to buy the clothing or shelter needed for protection. In such cases, the community may be responsible for providing the protection that homeless people are not able to provide for themselves.

See also: Hypothermia.

FOR MORE INFORMATION

Books

The Burton Goldberg Group. Alternative Medicine: The Definitive Guide. Puyallup, WA: Future Medicine Publishing, 1993.

McCauley, Robert L., et al., "Frostbite and Other Cold-Induced Injuries," in Paul S. Auerbach, ed. Wilderness Medicine: Management of Wilderness and Environmental Emergencies. St. Louis: Mosby, 1995.

Wilkerson, James A., and Cameron C. Bangs, eds. Hypothermia, Frostbite, and Other Cold Injuries: Prevention, Recognition and Pre-Hospital Treatment. Seattle, WA: Mountaineers Books, 1986.

Periodicals

Gill, Paul G., Jr., "Winning the Cold War." Outdoor Life (February 1993): pp. 62+.