Frostbite & Other Cold Injuries

Winter cold and snow provide a number of opportunities to get outside and participate in activities such as skiing, sledding and snowmobiling. However, without proper protection, cold injuries, such as frostbite, can occur even when the temperature is above freezing (32 degrees F, 0 degrees C). This is especially true if there is a high wind or if a glove or sock gets wet. The information below describes these types of cold injuries as well as what to do to prevent and treat them prior to reaching a healthcare provider.

What type of injuries can be caused by the cold?

Cold injuries are divided into two general groups: those that occur without any freezing of the body tissues and those that result from the freezing of the skin or a body part (generally the fingers, toes, ears or nose). Examples of cold injuries without tissue freezing include chilblains and "trench foot." Frostbite is a cold injury that is associated with tissue freezing.

Cold Injury Without Tissue Freezing

Chilblains

Chilblains is the most common type of cold injury and occurs when there is exposure of the affected area to a dry cold. There is no tissue freezing with a chilblain injury. If you have chilblains, you might notice that the affected area may itch, turn reddish-blue, and be swollen and painful. With time, blisters containing clear fluid may form. The injured area may be very sensitive to the cold in the future. However, there is usually no other permanent damage.

Trench Foot (Immersion Injury)

The cold injury called "trench foot" was named after the condition suffered by many soldiers in the trenches during World War I. "Trench foot," also known as immersion injury, occurs when a body part is exposed to a cold, wet environment. This type of injury may occur when a glove or sock becomes wet. As with chilblains, the affected area is not frozen. The symptoms of immersion injury are similar to those of chilblains, but the damage is usually more serious. The blisters are deeper and resemble the blisters that form after a burn. Again, there is no permanent injury other than cold sensitivity.

Cold Injury with Tissue Freezing

Frostbite

Frostbite occurs when there is freezing of the injured area. When an area of the body freezes, ice crystals form within the cells. These ice crystals cause the cells to rupture, leading to cell death.

Frostbite goes through several stages. When only the surface skin is frozen, the injury is called "frostnip" (a first degree injury). Frostnip begins similarly to chilblains with itching and pain. The skin then "blanches" or looses its blood supply. Eventually, the area loses feeling and becomes numb. Frostnip generally does not lead to permanent damage because only the top layers of skin are involved. Long-term sensitivity to cold can occur from frostnip.