Frostbite is the actual freezing of body tissue. It is produced by exposure of flesh
without adequate protection to freezing temperatures, usually below 20F (-7C). The
degree of injury depends upon the actual temperature, the amount of wind present, the
amount and quality of protection, the casualty's history of previous cold injury, and the
length of time the person was exposed. The ears, face, hands, wrists, and feet are
usually the first parts of the body to be frostbitten. Frostbite is classified as being either
superficial or deep.
a. Superficial Frostbite. The following are signs and symptoms of superficial
(1) Blanching. The onset (beginning) of frostbite is signaled by a sudden
blanching (loss of color) of the skin on the nose, ear, cheeks of the face, fingers, and/or
(2) Brief tingling. Blanching is followed by a momentary tingling sensation in
the affected part. Frostbite begins when the tingling or hurting sensation stops.
(3) Redness. After the tingling feeling stops, the affected area becomes red
and swollen. In dark-skinned individuals, the affected area may appear dull and
(4) Flaking skin. Redness may be followed by a sloughing (shedding) of
powdery or branny flakes of skin on the affected area.
(5) Blisters and sloughing. Blisters and sloughing of the skin in sheet-like
layers may occur 24 to 36 hours after exposure to freezing temperatures. Since these
signs are delayed, frostbite can enter into the deep phase without these signs being
b. Deep Frostbite. Signs of deep frostbite are always preceded by signs of
superficial frostbite. Deep frostbite is most common in the feet. If frozen flesh is not
rewarmed properly, gangrene and nerve damage usually result.
(1) Frozen flesh. In deep frostbite, the exposed flesh freezes. The frozen
flesh feels solid or "wooden" to the touch, but is not brittle.
Loss of feeling. The frozen area is completely numb and without pain.
(3) Blisters. Small blisters may appear in 12 to 36 hours unless rewarming
occurs quickly. A red-violet discoloration appears spontaneously 1 to 5 days after the