First, let’s define what frostbite is. Frostbite is the freezing of the skin and underlying tissue, which causes damage that can lead to tissue death and maybe amputation. Ice crystals literally form within the body tissue, irreversibly destroying cells. Frostbite does not appear as black or purple lesions on the skin, or at least not at first. Frozen flesh will be pale and stiff, and there may be a few blisters. It’s after thawing when the frostbite areas will turn red or purple. Black is a sign of tissue death.
Do you know the difference between frostbite and frostnip? Find out here.
So those iconic pictures of mountaineers with purple and black on their faces is usually seen after their frozen nose has thawed. It’s extremely painful, and recovery or amputation depends on the degree of frostbite damage. Read this post to learn more about the classifications of frostbite.
Wind chill and low temperatures in the winter are a deadly duo. Not only will it cause the human body to lose heat more rapidly, the combo can create perfect conditions for frostbite if time allows. Take a look at the Wind Chill Index chart below from the National Weather Service. As you can see, if temperatures are at 35F (1.6 C) with wind at 20 mph, frostbite could occur within 30 minutes. Of course, as temperature drops and wind speed increases, the time of frostbite onset shortens. For more about ways the body loses heat in the wilderness, see this post.
Some people are more prone to develop frostbite than others. Factors predisposing a person to frostbite are the same as those for hypothermia. Risk factors include exhaustion, diabetes, hypothyroidism, iron deficiency, anorexia, renal failure, tricyclic antidepressants, narcotics, benzodiazepines, steroids, caffeine, alcohol and nicotine.
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Frostbite Prevention = Perfusion + Protection
- Perfusion - (A.K.A. circulation or blood flow) Good blood flow to the extremities, fingers, toes, ears, and nose will help hinder body tissue from freezing. Factors that encourage adequate blood flow are maintaining core body temperature, proper hydration, nutrition, and avoiding the restriction of blood flow with tight clothing or footwear. It’s also a good idea to avoid drugs or foods that cause the blood vessels to constrict, like coffee or energy drinks. And if you are mountaineering, use supplemental oxygen at extreme altitudes.
- Protection - Protect all skin and extremities from the cold. Avoid perspiration and moisture, wet clothing will quickly drop your skin and core body temperature. Use insulation like gloves and other clothing. Use chemical or electrical hand and foot warmers (not directly in contact with skin), perform “cold checks” to periodically assess for the development of frostbite, and minimizing exposure in extreme conditions.
Review the signs and symptoms of frostbite here.
Prevention is better than treatment, especially in the case of frostbite. Treatment is very particular for frostbite. It is not a simple as rubbing your hands together to warm them up. In fact, you should never rub a frostbite area. Here, we cover how care for frostbite and when to thaw frostbite if you are in the wilderness far from help.
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