[ The Real McCoy Online Home ]                                                                                                                     January 14, 2011

Cold-weather injuries

Some of the more common cold-weather maladies, according to “Knowledge,” the official safety magazine of the U.S. Army, are:

Chilblains are a nonfreezing cold injury resulting from repeated, prolonged skin exposure to cold and wet (high humidity) temperatures above freezing. Exposed skin becomes red, tender and hot to the touch and usually is itchy. These symptoms can worsen to an aching, prickly (pins and needles) sensation and then numbness. Chilblains can develop in exposed skin in only a few hours. The most commonly affected areas are the ears, nose, fingers and toes.

Immersion Foot/Trench Foot
Immersion foot/trench foot is a nonfreezing injury that results from prolonged exposure to wet conditions between 32 degrees Fahrenheit to 60 degrees Fahrenheit or inactivity with damp socks and boots. Immersing feet in cold water, not changing socks frequently, not maintaining proper hygiene and allowing sweat to accumulate inside boots or socks will soften the skin, causing tissue loss and often infection. Symptoms in affected areas include cold, swollen, discolored and waxy flesh accompanied by tingling sensations, numbness and pain. In extreme cases, the flesh dies and amputation may be necessary.

Frostnip is the freezing of the top layers of skin tissue and is considered the first degree of frostbite. Frostnip usually results from short-duration exposure to cold air or contact with a cold object such as metal. Exposed skin such as the cheeks, ears, fingers and wrists are more likely to develop frostnip. The top layer of frozen skin becomes white and waxy and feels hard and rubbery while the deeper tissue is still soft. Affected areas feel numb and may become swollen but do not blister. Frozen skin thaws quickly, becoming red and painful with eventual peeling. Complete healing usually occurs within 10 days, and frostnip normally is reversible.

Frostbite is the actual freezing of skin tissue. It can extend through all layers of the skin and freeze muscle and bone. Frozen skin may turn red and then gray-blue with blisters. In the worst cases, the skin dies and turns blue-black. At this stage, amputation often is required. Deeply frozen skin feels “wooden” to the touch and the affected body part is too stiff to move. Instantaneous frostbite can occur when skin comes in contact with super-cooled liquids, including petroleum, oils and lubricants; fuel; antifreeze; and alcohol — all of which remain liquid at temperatures as low as minus 40 F.

Hypothermia is a potentially life-threatening condition. It is defined as a general cooling of the body’s core temperature below 95 F (normal body temperature is 98.6 F).

Hypothermia sets in when body heat loss exceeds the body’s heat production due to prolonged cold exposure. Although hypothermia usually is associated with cold climates, it can occur at temperatures well above freezing, especially when a person is exposed to wet conditions over an extended period of time. Signs and symptoms of hypothermia change as body temperature falls.

Mental functions typically decline first, marked with impaired decision-making ability, slurred speech, disorientation, incoherence, irrationality and possible unconsciousness. Muscle functions deteriorate with shivering and loss of fine-motor ability (e.g., unable to complete tasks with hands), progressing to stumbling, clumsiness and falling.

In severe cases, shivering ceases and the victim exhibits stiffness and an inability to move. Pulse and respiration rates can decrease, progressing to unconsciousness, irregular heartbeat and death. Unfortunately, early signs and symptoms of hypothermia can be difficult to recognize and may go undetected. Victims may deny they are in trouble, so believe the symptoms, not the victim.

Dehydration is a lack of water in the body. Most people associate dehydration with hot weather, but it is very easy to become dehydrated in cold weather. Soldiers can fall victim to dehydration when they fail to drink enough liquid and underestimate fluid loss from sweating.

Proper hydration is especially important in cold weather because dehydration adversely affects the body’s resistance to cold injury, increasing the chance of cold-weather injuries. Remember that proper hydration is essential to supplying the fuel and energy necessary for heat production.

More Fort McCoy safety information is available at the safety section of the Fort McCoy Extranet (available through the Fort McCoy public website at http://www.mccoy.army.mil) or by calling the ISO at 608-388-3403.

(See related story.)

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