The Dangers of Heat and Cold: Frostbite

Exposure to cold temperatures causes blood vessels near the surface of the body to constrict, reducing blood flow and loss of heat to the surrounding environment. This serves as one of the body’s protective measures against hypothermia, or cooling of the core body temperature. Sometimes there is an unfortunate side-effect of this mechanism, especially in sub-freezing temperatures. It is known as frostbite. When the temperature of the skin or extremities dips below freezing, the water and liquids inside and between cells begin to crystallize. As the water freezes, the microscopic ice crystals rupture and kill cells, causing irreversible tissue damage.

In the past doctors have advocated multiple and sometimes confusing classification systems for assessing the severity of frostbite. Recently some experts have moved towards describing frostbite as either “superficial” or “deep.” Since it’s simple, easy to remember, and effective, we’ll use this method.

The symptoms of superficial frostbite begin with stinging or pain in the affected area, followed by a feeling of numbness and cold. Superficial frostbite may appear as a white or gray patch of skin with surrounding redness. As the condition worsens clear blisters may form in the affected area. Upon palpation, the skin will still feel soft and malleable. If pressing a finger against the affected skin leaves an indentation, there is still healthy tissue underneath the damaged skin.

If the skin is hard to the touch, frostbite may have already reached the deeper tissues. Deep frostbite is also often accompanied by black hemorrhagic blisters and dry, black, necrotic tissue.

Frostbitten limbs or appendages should be rewarmed by immersion in luke-warm or tepid water (about 100°F). However, rewarming should only take place if there is no risk of refreezing. Partial thawing followed by refreezing results in more damage than extended freezing alone. If warmth cannot be maintained, avoid rewarming frostbitten extremities until such a time that continued warmth can be guaranteed. After rewarming, frostbite victims experience severe throbbing pain and redness. Many victims also complain of a persistent prickling or tingling feeling that can last for weeks. Long-term symptoms include cold sensitivity, numbness, and excessive perspiration.

Rubbing or massaging frostbitten areas of the body is not recommended, since it will only worsen the condition of the already-damaged tissues. Pressure dressings or elastic bandages reduce circulation and are not recommended unless necessary to stop bleeding from another injury. In any case of frostbite, medical attention should be sought out as soon as possible, preferably at a burn or trauma center. In severe cases of frostbite there is an extremely high risk of infection, gangrene, and other complications.

As always, the first and most important step in managing frostbite is prevention. Gaining the appropriate knowledge and training is a big step in the right direction. Be aware that extremities such as toes, fingers, ears, lips, and the nose are at the highest risk for frostbite. If you will be pursuing an activity where cold weather is a possibility, always pack for the worst-case scenario. Make sure you’ll have a spare change of dry, warm clothes available, including gloves, socks, and something to cover the head, ears, and face.