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Frostbite is an injury caused by freezing of the skin and underlying tissues. First your skin becomes very cold and red, then numb, hard and pale. Frostbite is most common on the fingers, toes, nose, ears, cheeks and chin. Exposed skin in cold, windy weather is most vulnerable to frostbite. But frostbite can occur on skin covered by gloves or other clothing.
Frostnip, the first stage of frostbite, doesn’t cause permanent skin damage. You can treat very mild frostbite with first-aid measures, including rewarming your skin. All other frostbite requires medical attention because it can damage skin, tissues, muscle and bones. Possible complications of severe frostbite include infection and nerve damage.
Frostbite is the medical condition in which localized damage is caused to skin and other tissues due to freezing. Frostbite is most likely to happen in body parts farthest from the heart and those with large exposed areas.
Your body works to stay alive first, and to stay functioning second.
- In conditions of prolonged cold exposure, the body sends signals to the blood vessels in the arms and legs telling them to constrict (narrow). By slowing blood flow to the skin, the body is able to send more blood to the vital organs, supplying them with critical nutrients, while also preventing a further decrease in internal body temperature by exposing less blood to the outside cold.
- As this process continues and the extremities (the parts farthest from the heart) become colder and colder, a condition called the hunter’s response is initiated. The body’s blood vessels are dilated (widened) for a period of time and then constricted again. Periods of dilatation are cycled with times of constriction in order to preserve as much function in the extremities as possible. However, when the brain senses that the person is in danger of hypothermia (when the body temperature drops significantly below 98.6 F [37 C]), it permanently constricts these blood vessels in order to prevent them from returning cold blood to the internal organs. When this happens, frostbite has begun.
- Frostbite is caused by two different means: cell death at the time of exposure and further cell deterioration and death because of a lack of oxygen.
- In the first, ice crystals form in the space outside of the cells. Water is lost from the cell’s interior, and dehydration promotes the destruction of the cell.
- In the second, the damaged lining of the blood vessels is the main culprit. As blood flow returns to the extremities upon rewarming, it finds that the blood vessels themselves are injured, also by the cold. The vessel walls become permeable and blood leaks out into the tissues. Blood flow is impeded and turbulent and small clots form in the smallest vessels of the extremities. Because of these blood flow problems, complicated interactions occur, leading to inflammation that causes further tissue damage. This injury is the primary determinant of the amount of tissue damage that occurs in the end.
- It is rare for the inside of the cells themselves to be frozen. This phenomenon is only seen in very rapid freezing injuries, such as those produced by frozen metals.
Symptoms of Frostbite
Symptoms of frostbite include:
- Pins and needles feeling, followed by numbness
- Hard, pale, and cold skin that has been exposed to the cold for too long
- Aching, throbbing or lack of feeling in the affected area
- Red and extremely painful skin and muscle as the area thaws
Very severe frostbite may cause:
- Gangrene (blackened, dead tissue)
- Damage to tendons, muscles, nerves, and bone
Frostbite may affect any part of the body. The hands, feet, nose, and ears are the places most prone to the problem.
- If the frostbite did not affect your blood vessels, a complete recovery is possible.
- If the frostbite affected the blood vessels, the damage is permanent. Gangrene may occur. This may require removal of the affected body part (amputation).
How common is frostbite and who gets it?
Frostbite is uncommon in the UK. Frostbite most commonly affects the following groups of people:
- People who work outdoors in the cold.
- Homeless people.
- Winter outdoor sports enthusiasts such as skiers and climbers.
However, it can affect anyone who is exposed to low temperatures (below freezing) – in particular, those who wear inadequate clothing.
If you have underlying health problems such as narrowing of the arteries, mainly occurring in the legs (peripheral vascular disease) or diabetes, you have an increased risk of developing frostbite.
If you take certain medicines that narrow (constrict) your blood vessels, your risk is increased. Beta-blockers are a good example of this.
You are more at risk of developing frostbite if you smoke, as the chemicals in cigarettes can cause your blood vessels to constrict.
What Are the Treatments for Frostbite?
Most people recover completely from frostbite, though the affected area may be more susceptible in the future to discomfort from cold weather, repeat frostbite, and damage from the sun. The first goal of treatment is to re-warm the affected area.
Frostnip can be treated at home. If you think you may have frostnip, get out of the cold as soon as possible. If your clothes are wet, change into dry clothing. Immerse the affected area in warm water (100º to 105º Fahrenheit) to thaw the frozen tissue. Do not use hotter water as this may burn your skin. If warm water is not available, use your own body heat by, for instance tuck your hands into your armpits or cover your nose, ears, or face with dry hands.
CAUTION: Do not rub the affected area because this may increase damage to the tissue. Do not use a heating pad, heat lamp, stove, fireplace, or radiator to rewarm the affected area. These methods may warm your skin unevenly or may burn your skin, particularly if it’s numb and you cannot tell how hot the skin is getting.
If the skin tingles and burns as it warms, your circulation is returning. The skin may turn red, but should not blister or swell. If the skin does not seem to warm, if it remains numb, or if it does blister or swell, seek immediate medical attention.
Frostbite requires emergency medical care. If you think you may have frostbite, get out of the cold as soon as possible. If you cannot get medical help immediately and there’s no risk that the area might be re-frozen before you get help, warm the affected area as you would for frostnip.