Correct statement(s) concerning cold injury include:

a. Chilblain is a form of local cold injury characterized by pruritic papules, macules, or plaques on the skin associated with repeated exposure to cold temperatures

c. Frost nip is reversible with warming of the tissue and will result in the return of sensation and function with no tissue loss

Cold injuries limited to digits, extremities, or exposed surfaces are the result of either direct tissue freezing (frostbite) or more chronic exposure to an environment just above freezing (Chilblain or pernio; trenchfoot). Chilblain or pernio are descriptive forms of local cold injury characterized by pruritic, red-purple papules, macules, plaques or nodules in the skin. This pathology appears to be provoked by repeated exposure to cold but not freezing temperatures. Trenchfoot or cold emersion foot describes a non-freezing injury of the hands or feet, typically in sailors, fishermen, or soldiers resulting from chronic exposure to wet conditions and temperatures just above freezing. Frost nip is the mildest form of cold injury characterized by initial pain, pallor, and subsequent numbness of the affected body part. The injury is reversible and warming of the cold tissue results in return of sensation and function with no tissue loss. Frostbite is more severe and common form of cold injury and essentially describes local freezing of tissues. The mildest form (first degree injury) is associated with hyperemia and edema but without blistering. Second, third and fourth degree frostbite have progressive degrees of tissue injury and are noted by either characteristic clear blisters (second degree) or more hemorrhagic vesicles which are generally smaller than second degree blisters (third degree frostbite). In fourth degree frostbite, tissue necrosis, gangrene and full thickness tissue loss can be seen.