Frostnip is characterized by:

• A. Numbness and whiteness with reversible superficial freezing.
• B. Deep tissue freezing with tissue loss.
• C. Does not involve the skin.
• D. Permanent numbness.

Answer: (A)

Frostnip is a mild cold injury that affects only the surface of the skin. The skin appears pale or white and is numb due to superficial freezing and vasoconstriction, but there is no tissue damage. Because the freezing is shallow, warming restores sensation and color without lasting injury—it's reversible with proper rewarming.

This differs from frostbite, where freezing penetrates deeper into tissues and can lead to tissue damage or loss, so the deep tissue freezing with tissue loss describes frostbite, not frostnip. The statement that frostnip does not involve the skin is not correct, since frostnip clearly involves the skin. Permanent numbness would indicate deeper injury or nerve damage typically associated with frostbite, not frostnip.