Frostbite is a severe and localized cold-induced injury most commonly affecting the ears, nose, cheeks, chin, fingers, and toes. It is further classified as first degree (superficial localized pallor and surrounding edema), second degree (large blisters that may form eschar), third degree (deeper and smaller hemorrhagic blisters), and fourth degree (tissue necrosis extending to muscle and bone). Diagnosis is usually clinical in susceptible individuals (eg, the homeless, mountaineers, soldiers, those stranded or working in the cold). Technetium (Tc)-99 scintigraphy may predict long-term viability of affected tissue. Treatment involves rapid rewarming with water heated to 37-39 C (98.6-102.2 F) (not hot) to reduce tissue damage and analgesics (eg, opioids) for pain control.
After thawing is complete (usually in 15-30 minutes), localized tissue usually appears red or purple and is soft to the touch. After rewarming, the affected areas are usually air dried and covered with a first layer of nonadherent gauze using aseptic technique. Other treatment measures include tetanus prophylaxis, possible splinting to prevent contractures, daily hydrotherapy, and elevation of the affected area (to reduce edema). Severe frostbite may require early surgical consultation for possible tissue debridement, escharotomy, or amputation.