frostbite

Frostbite is tissue damage caused by freezing of the skin and deeper tissues due to exposure to cold, wind, and moisture. It most often affects the fingers, toes, ears, nose, and cheeks and commonly occurs during winter activities or in outdoor work.

Causes include prolonged exposure to freezing temperatures, especially with wind chill or wet conditions. High-risk groups include outdoor workers, mountaineers, swimmers, the elderly, and children, as well as people under the influence of alcohol or sedatives.

Pathophysiology involves ice crystal formation within and around cells, reduced blood flow, and inflammatory responses that can lead to tissue necrosis. Frostnip is a milder, reversible form with numbness that does not involve deep tissue freezing; frostbite affects deeper layers.

Staging commonly includes frostnip, superficial frostbite, and deep frostbite. Frostnip presents with cold, pale skin and numbness. Superficial frostbite features waxy skin and blisters; deep frostbite causes hard, white or blue skin with loss of sensation and possible tissue death.

Diagnosis is clinical. Imaging and lab tests are not routinely needed unless deep tissue injury is suspected or to guide procedures. Assess for hypothermia and other cold injuries.

Treatment focuses on safe rewarming and prevention of further injury: move to a warm environment, remove wet clothing, and avoid rubbing. Rewarm in 37–39 C water for 15–30 minutes until sensation returns, then protect blisters and dress wounds. Do not refreeze tissue or apply dry heat; seek medical care for deep frostbite or infection. Prognosis ranges from good for mild frostbite to permanent impairment with deep injury; prevention includes appropriate clothing, keeping dry, and avoiding excessive alcohol.