Fluid is released into the tissues and is accompanied by local inflammation. The toes, fingers, nose, ears, and cheeks, are the most common sites of freezing cold injury. Frostnip is a mild, reversible freezing of the top layers of skin tissue. Frostbite can be superficial or deep. If there is superficial frostbite, the individual experiences a loss of sensation and the skin turns gray-white.
Deep frostbite affects the skin and the subcutaneous tissues, as well as the muscle and bone.
Deep frostbite will cause numbness. The affected area will be cold, hard and white. If there is absolutely no possibility of the tissue refreezing, the frozen tissue may be rewarmed and insulated until medical attention is received. Caution must be used to avoid applying excessive heat to rewarm frozen tissue, since this may produce a devastating secondary burn injury. It may occur in wet, cold environments or through actual immersion in water.