Tips Offered to Prevent Cold Weather Injuries

Stripe-News and information for Walter Reed Army Medical Center Personnel

Cold weather injuries have been a concern throughout military history. These injuries are broken down into two categories -- freezing and nonfreezing.

Freezing cold injuries occur whenever air temperature is below 32 degrees Fahrenheit. Freezing limited to the skin surface is called frostnip. Frostnip involves freezing of water on the skin surface, causing the skin to become reddened and possibly swollen. Although painful, there is usually no further damage after rewarming the damaged area.

Repeated frostnip in the same area can dry the skin, causing it to crack and become very sensitive. Frostnip should be taken seriously since it may be the first sign of frostbite.

When freezing extends deeper through the skin and flesh, the injury is called frostbite. Frostbite occurs when skin tissue and blood vessels are damaged. As frostbite develops, skin will become numb and turn to a gray or waxy-white color. The area will be cold to the touch and may feel stiff or woody. With frostbite, the forming of ice crystal formation and the lack of blood flow to a frozen area damages the tissues. After thawing, swelling may occur, worsening the injury.

Freezing cold injuries most commonly affects the toes, fingers, earlobes, chin, cheeks, and the nose the body parts that are often left uncovered in cold temperatures.

Nonfreezing cold injuries can occur when conditions are cold and wet (air temperatures between 32 and 55 degrees Fahrenheit) and the hands and feet cannot be kept warm and dry. The most prominent nonfreezing cold injuries are chilblain and trench foot.

Chilblain is an inflammatory swelling or sore caused by exposure to cold and wetness. It appears as red, swollen skin, which is tender, hot to the touch, and may itch. This can worsen to an aching, prickly ("pins and needles") sensation, and then numbness. While painful, it causes little or no permanent impairment.

Trench foot is a very serious cold injury which develops when the skin of the feet is exposed to moisture and cold for prolonged periods. The average duration of exposure resulting in trench foot is three days. Often, the first sign of trench foot is itching, numbness or tingling pain. Later the feet may appear swollen, and the skin mildly red, blue or black. Untreated, trench foot can eventually require amputation. Nonfreezing cold injuries mostly occur in the lower limbs of the body, such as the lower legs and the feet.

Ways of preventing cold weather injuries are:

* Wear several layers of clothing, rather than one or two "bulky" layers. Air is trapped between these layers and acts as insulation against the cold. Clothing filled with wool, down, and synthetic foams may help retain body heat.

* Always wear a hat, scarf and facemask. As much as 70 percent or more of the body's heat can be lost through radiation and convection from an uncovered head. A scarf or facemask may help prevent frostbite injuries to the nose and ears.

* Drink warm liquids like tea and hot chocolate. Sugar contained in these beverages helps the body to generate additional heat. Avoid alcoholic and caffeine beverages, which can give people a false sense of warmth.

* Avoid wet clothing, shoes and socks.

* Insulated gloves and socks may help to prevent frostbite injuries to fingers and toes. Avoid skin contact with metal objects exposed to the cold for extended periods.

November 22, 2002
by Marques Walker
Preventive Medicine