injury to tissues due to exposure to cold. Usually the first areas of the body to freeze are the nose, ears, fingers, and toes. The flesh feels cold to the touch, and frozen parts become pale and feel numb. There may also be some prickly or itchy sensation. A person suffering from frostbite may feel no warning pain. In mild cases, proper treatment can rather quickly restore normal circulation of blood. In more serious cases the area may become painfully inflamed, and blistering may follow. Especially severe frostbite can cause death of the injured tissues and
gangrene.
Mild frostbite usually appears as a shallow, blanched wheal on the nose, ears, fingers, or toes. After rewarming, the area is slightly reddened for several hours and then resumes a normal appearance. If the frostbite is more severe, deeper tissues are affected and the area appears waxy and feels doughlike to the touch. With rewarming, the area becomes edematous and the patient feels itching, burning, and deep pain. Later on, mild edema may remain and the skin becomes mottled, cyanotic, or red without blistering. Over the following weeks the pain and edema should subside, but the skin may peel and the patient may experience increased sensitivity to cold in that area until healing is complete.
Blistering occurs in deeper frostbite. The vesicles may contain pink or clear fluid that has leaked from damaged cells and tissues. Eventually the vesicles contract and dry out, leaving an eschar that sloughs off and exposes new skin underneath if there has been adequate circulation to the part.
Severe frostbite damages all layers of soft tissue down to connective tissue and bone. The frostbitten area is hard and wooden and appears lifeless. There is no sensation of pain and the patient cannot voluntarily move the frozen part. With rewarming there are aching pain, burning, and blistering. If there is no pain or other sensation after rewarming, the tissue may be dead and amputation may be indicated.
Treatment. Rewarming is best done in an emergency care facility where assessment of the extent of frostbite can be done and appropriate measures taken to rewarm the frostbitten part without further damaging tissue. In the field, it is best to keep the part as warm as possible to prevent further freezing. Blankets and warm clothing are appropriate and, if possible, the frozen area can be placed in contact with any other part of the body that is warm. Rubbing and massaging the area is not recommended because it can only serve to further damage frozen tissue. The victim should not smoke and should avoid caffeine and alcohol because any of these can further restrict blood circulation.
Emergency medical care, if the patient cannot be brought to the hospital and rewarming must be done in the field, includes rapid rewarming in water baths not exceeding 40.6°C (105°F). Hot water can cause further tissue destruction. Tetanus prophylaxis is administered as necessary. If severely frostbitten tissue swells to the point of totally restricting circulation, a fasciotomy may be required to allow adequate blood supply. Vesicles are left intact but frostbitten fingers and toes should be separated with cotton balls and a loose dressing applied. If the patient will be taken outside for transport to a medical facility, rewarming should be started at the hospital.