Frostbite

Frostbite is a localized cold injury in which body tissue freezes. It occurs when tissue temperature falls sufficiently for ice to form within the tissue, most often affecting exposed or poorly insulated areas such as the fingers, toes, ears, and nose. The severity depends on factors including temperature, duration of exposure, wind, moisture, and local blood flow .^1,2

Frostbite injury develops through both direct freezing and subsequent damage to the circulation. Ice crystal formation and shifts in water and electrolytes can injure cells, while cold-induced constriction of blood vessels reduces tissue perfusion. During and after thawing, microvascular injury, inflammation, and thrombosis can produce further ischemic damage. Severe frostbite can therefore lead to irreversible tissue death .^1,2

Frostbite is distinct from frostnip, a milder cold injury in which tissue does not freeze. In frostnip, numbness and pallor resolve after warming without permanent tissue damage. Frostnip can, however, occur under conditions that also favor the development of frostbite .¹

Frostbite is also different from hypothermia. Frostbite is primarily a localized freezing injury to tissues, whereas hypothermia is a fall in the body's core temperature below 35°C. The two conditions can occur at the same time during severe cold exposure but describe different physiological problems .¹