What is frostbite?

Frostbite is freezing of the skin and body tissues just under the skin. It can occur when part of your body is exposed to temperatures or wind chills at or below freezing.

Full recovery from frostbite is likely if damage is limited to the skin and uppermost tissue layers. Permanent damage may result when blood vessels are injured. Tissues then die because of the lack of oxygen.

How does it occur?

When parts of the body are exposed to freezing temperatures for too long, the flow of blood to the area stops and body tissues are damaged. The top layer of skin, along with the tissues and blood vessels underneath, can be injured. Strong winds during cold weather can quicken the tissue damage. The areas most often affected are the nose, cheeks, ears, fingers, and toes.

What are the symptoms?

Frostbitten skin may:

• feel prickly or have no feeling

• be hard, pale (white or blue), and cold

• become red, swollen, and painful as it warms up

• become blistered or turn black if frostbite is severe.

How is it diagnosed?

Frostbite is diagnosed from your history and an exam of the affected area for signs of frostbite.

What is the treatment?

Treatment for frostbite must begin promptly, ideally by emergency medical personnel. If medical help is not available, find shelter and give first aid as quickly as possible.

Thaw the affected area by one of these methods:

• Immerse the area in warm water (about 105 degrees F, or 40 degrees C).

• Dry and cover the area with warm clothes and then layers of blankets.

• Warm the area with warm parts of the body, such as the armpits or abdomen.

The person with frostbite should drink hot fluids such as coffee or tea. Never drink alcohol or smoke. Never rub, apply snow to, or put intense, direct heat on the frostbitten areas. If the feet or toes are frozen, do not walk on them and keep the feet raised.

Rewarming takes up to an hour and can be painful. Acetaminophen, ibuprofen, or aspirin may be taken for the pain.

Normal color and feeling should return to the skin. Cover the thawed area, which may become blistered, with a clean bandage or cloth.

If the frostbitten areas do not look normal after thawing, go to an emergency medical facility at once. Treatment at an emergency medical facility may include:

• a shot of a strong pain reliever

• rapid rewarming of the affected area in warm water, such as a whirlpool bath

• hyperbaric oxygen (oxygen at greater than normal atmospheric pressure) given in a special chamber to deliver high levels of oxygen to frostbitten tissues.

How long will the effects of frostbite last?

Rewarming the skin from the frostbite takes up to an hour.

The length of time for recovery from frostbite depends on the amount of tissue damage. Often skin damage is temporary if it is treated promptly and only the top layers are affected. You may not know the full extent of damage until 6 weeks after the frostbite.

Frostbitten skin will be very sensitive to cold temperatures for several months or longer.

When underlying blood vessels are damaged by frostbite, cutting off blood supply, the tissue dies. This dead tissue can become infected. Gangrene is possible and can be fatal. Sometimes the dead area has to be amputated, which can mean the loss of fingers, toes, or other frostbitten body parts. Amputation should be performed only by someone experienced with treating frostbite injury. However, amputation does not have to be done in every case. Often the blackened areas of severe frostbite heal if they are properly cared for under medical supervision.

How can I take care of myself?

Try to prevent frostbite. Seek shelter before your judgment becomes impaired, which is likely in the situations where you might become frostbitten.

If you have frostbite, remember that prompt treatment is very important. Find shelter as soon as possible, try to warm the affected areas, and drink hot fluids. Do not drink alcohol, smoke, rub the affected areas, walk on frozen toes or feet, or go back out into the cold. Get medical help as soon as possible.

What can be done to help prevent frostbite?

Follow these guidelines:

• Be aware of the wind chill effect even when the temperature is over 32 degrees F (0 degrees C).

• Dress in layers of warm clothing protected by an outer covering that is windproof and waterproof.

• Be sure your clothing provides protection for your head, ears, nose, hands, and feet. Also, try to keep your hands and feet dry.

• Watch for any numbness or prickly feelings, which may mean that you are starting to get frostbitten. Avoid alcoholic beverages, which might cause you to ignore these signals of frostbite.

• Memorize the first aid treatment for frostbite.

• Rewarm fingers or hands by tucking them in your armpits.

• Find out if any drugs you are taking increase your potential for frostbite (for example, heart medicines such as beta-blockers).

• Take extra precautions if you have atherosclerosis or any other condition that affects your blood flow.