Acute bilateral hand edema and vesiculation

Diagnosis: Second-degree frostbite

Frostbite is the result of tissue freezing, which generally occurs after prolonged exposure to freezing temperatures (typically –4°C or below).^1,2 The majority (~90%) of frostbite injuries occur in the hands and feet; however, frostbite has also been observed in the face, perineum, buttocks, and male genitalia.³

Angiography should be performed on patients with third- or fourth-degree frostbite. In cases of vascular occlusion, tPA and heparin can be started to reduce the risk for amputation.

Frostbite is a clinical diagnosis based on a history of sustained exposure to freezing temperatures, paresthesia of affected areas, and typical skin changes. Evidence is lacking regarding the epidemiology of frostbite within the general population.²

Pathophysiology. Intra- and extracellular ice crystal formation causes fluid and electrolyte disturbances, cell dehydration, lipid denaturation, and subsequent cell death.¹ After thawing, progressive tissue ischemia can occur as a result of endothelial damage and dysfunction, intravascular sludging, increased inflammatory markers, an influx of free radicals, and microvascular thrombosis.¹

Classification. Traditionally, frostbite has been classified according to a 4-tiered system based on tissue appearance after rewarming.² First-degree frostbite is characterized by white plaques with surrounding erythema; second degree by edema and clear or cloudy vesicles; third degree by hemorrhagic bullae; and fourth degree by cold and hard tissue that eventually progresses to gangrene.²

A simpler scheme designates frostbite as either superficial (corresponding to first- or second-degree frostbite) or deep (corresponding to third- or fourth-degree frostbite) with presumed muscle and bone involvement.²

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