Superficial Frostbite

Erythema and bulla formation characterize the typical lesions of superficial frostbite. Deep frostbite, in contrast, involves subcutaneous tissue and usually leads to tissue loss. Below-freezing temperature and wind can combine to injure exposed skin within minutes. At special risk are the inexperienced young, the senile elderly, and intoxicated persons of all ages.

All 3 of the teenaged patients shown here incurred superficial frostbite in November and December, when temperatures in their home state of Minnesota ranged from -16ºF to +10ºF (-27ºC to -12ºC), often with associated strong winds. One girl (A) walked several blocks with the wind at her back. The gap between her skirt hem and the tops of her socks left her calves unprotected from the windchill effect. A boy (B) shoveled snow for 1 hour with his head and ears uncovered. Both of these young people recovered uneventfully.

A second girl (C), with the most localized injury of the 3, exposed her great toe to frostbite through a hole in her shoe. The toe became infected after she "popped" the blister with a needle. Debridement and oral cephalexin were necessary to resolve the infection. Intact bullae arising from frostbite contain sterile fluid and should not be disturbed. The best treatment for superficial frostbite is rapid rewarming of the involved body part in water at 100ºF to 106ºF (38ºC to 41ºC). Frostbitten tissue should never be rubbed to rewarm, because this further damages it. Once frostbitten, skin often remains hypersensitive to subsequent exposure and requires careful bundling against cold and wind.

(Case and photographs courtesy of David J. Roberts, MD.)