Frostbite
Frostbite is a freezing injury to tissue occurring when local tissue temperature falls below 0 °C. It most commonly affects acral sites (fingers, toes, nose, ears) and exposed skin. Severity ranges from transient superficial injury to deep, limb‑threatening tissue loss.
Emergency management aims to prevent further cold exposure or refreezing, recognise and treat coexisting systemic hypothermia, provide effective analgesia, perform rapid controlled rewarming when safe, and arrange timely specialist input.
Pathophysiology
- Freezing produces extracellular and intracellular ice, causing osmotic shifts, membrane disruption and direct cellular injury.
- Cold‑induced vasoconstriction and endothelial damage lead to stasis and microthrombus formation.
- Reperfusion after thaw generates inflammatory injury, oedema and severe pain.
- The combination of direct mechanical, osmotic and ischaemic injury determines depth and reversibility.
- Rewarming can unmask compartment syndromes and further microvascular compromise.
Classification
Frostbite can be described by depth (superficial vs deep) and by degree. Clinical grading guides initial management; definitive tissue outcome may take days-weeks to declare.
Clinical presentation
- History: nature and duration of cold exposure (wet vs dry), insulating clothing, alcohol/drug use, prior rewarming or refreezing, level of consciousness, comorbidities and social factors.
- Examination: early white/waxy, firm skin with numbness; blisters often develop hours after thaw.