Frostbite is the medical condition in which localized damage is caused to skin and other tissues due to freezing. Frostbite is most likely to happen in body parts farthest from the heart and those with large exposed areas.The initial stages of frostbite are sometimes called frostnip.he several classifications for tissue damage caused by extreme cold include: 1  Frostnip is a superficial cooling of tissues without cellular destruction. 2  Chilblains are superficial ulcers of the skin that occur when a predisposed individual is repeatedly exposed to cold.