Nonfreezing Tissue Injuries

In nonfreezing tissue injuries, parts of the skin are chilled but not frozen.

Nonfreezing tissue injuries include frostnip, immersion foot, and chilblains.

Frostnip is a cold injury in which the chilled areas of skin become numb, swollen, and red. The only treatment needed is warming the area for a few minutes. During warming, the area may hurt or itch intensely. No permanent damage results, although sometimes the area is particularly sensitive to cold for months or years afterward.

Immersion foot (trench foot) is a cold injury that develops when a foot is kept in wet, cold socks and boots for several days. The foot is pale, clammy, and cold. After warming, the foot becomes red and painful to the touch. Sometimes blisters develop, which may become infected. Treatment consists primarily of gently warming, drying, and cleaning the foot; elevating it; and keeping it dry and warm. Some doctors give antibiotics to prevent infection. A tetanus booster is given if the person's tetanus vaccination is not current. Rarely, this type of injury occurs in the hands. Immersion foot can often be prevented by changing socks and drying the feet at least daily.

Chilblains (pernio) is an uncommon reaction that may occur with repeated exposure to cold. Symptoms include itching, pain, and, in rare cases, discolored areas or blisters on the affected area (usually the leg). The condition is uncomfortable and recurrent but not serious. Preventing exposure to cold is the best treatment. The drug nifedipine, taken by mouth, sometimes relieves symptoms.