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When you are out in the cold, your body's first priority is to maintain its core (optimal) temperature. To do that, it shifts blood away from your extremities, such as your hands and feet, and toward the central organs of your body—the heart and lungs. This is your body's way of ensuring that blood flows to the organs that need it most. This redirection of blood, however, increases the risk of injury from cold to your fingers, toes, or other extremities.

Body tissues actually freeze when they are frostbitten. Ice crystals form in the cells, causing physical damage and permanent changes in cell chemistry. When the ice thaws, additional changes occur that may result in cell death.

There are two degrees of frostbite:

• Superficial frostbite occurs if only the skin surface is affected.
• Deep frostbite affects the underlying tissues, as well.

In this patient, deep frostbite caused permanent tissue damage and three toes on the right foot required amputation.

Frostbite is caused by exposure to very cold temperatures. The elderly and the young are particularly susceptible to frostbite. Other risk factors include:

• Not dressing properly for the weather, staying out in the cold too long, or getting wet while you are exposed to the cold.
• Having a medical condition that affects your circulation, such as diabetes and atherosclerosis.
• Having had a previous injury that was caused by the cold.
• Taking certain drugs, including alcohol and nicotine, or medications such as beta-blockers—which decrease the flow of blood to the skin.

It is important to recognize the signs of frostbite so that you can seek medical help, if needed. Symptoms include:

• The affected area becomes numb.
• The skin may feel frozen, but deeper tissues are soft (superficial frostbite) or the entire affected area feels solid, hard and frozen (deep frostbite).
• The skin may appear waxy, white, or grayish.

Seek medical care promptly if you suspect that you or someone you are with has frostbite. In some cases, frostbite can have very serious outcomes. The lack of blood flow and oxygen to the skin can cause the flesh to die, leading to permanent tissue damage. This may result in the need for amputation of the affected extremities. In some cases, an individual with frostbite will also develop hypothermia, another serious cold-weather condition that requires emergency medical assistance.

If medical care is not immediately available, follow these "do's and don'ts" for treating frostbite:

It is easier to prevent frostbite than it is to treat it. If you must go out in the bitter cold, be prepared.

Observing the five commonsense precautions below will help ensure that your winter outings end safely:

1. Dress appropriately.
   Light, loose, layered clothing provides both ventilation and insulation. Top off your outfit with a water-repellent (not waterproof) fabric.
2. Protect your head, hands, and feet.
   Substantial heat loss occurs through the scalp, so a warm hat is vital. Mittens are warmer than gloves, and two pair of socks (wool over lightweight cotton) will help keep your feet warm.
3. Do not drink alcohol or smoke before going out into the cold.
   Alcohol, caffeine, and nicotine leave the skin more prone to thermal injury.
4. If you get wet, get inside!
   Remove wet clothing as quickly as possible.
5. Check yourself every half hour or so for signs of frostbite.
   If your fingers, toes, nose, ears or any other body parts feel numb, go inside immediately.