Frostbite is injury to the skin and other tissues that results from prolonged exposure to cold. It can occur with exposure to below-freezing temperatures for several hours, or to above-freezing temperatures if there is a strong wind or if the person is at high altitude or wet. Frostbite usually affects the hands, feet, nose, cheeks, and ears; it can also affect the genitals in males. Superficial frostbite injures the skin and tissues just beneath it. It typically resolves in 3 to 4 weeks. Deep frostbite, which also affects muscle, nerves, and blood vessels, may result in tissue death, a condition known as gangrene.

The following are signs and symptoms of frostbite:

• Pain progressing to numbness
• White color and waxy appearance of the skin of affected area
• Blood rushing to area after it's rewarmed
• Burning sensation and swelling from collected fluid that may last for weeks
• Blisters
• Black scab-like crust, which may develop several weeks later

When exposed to cold conditions, the body tries to preserve heat. To do this, blood vessels near the skin's surface constrict, forcing more blood into the core. This helps prevent hypothermia, a lowering of the body's core temperature below 93°F (34°C). However, it also prevents the extremities from receiving enough blood, allowing them to become cold. At first, the blood vessels alternate between constricting and dilating, to keep the extremities as warm as possible. But under extremely cold conditions, the vessels stop dilating, as core temperature becomes the priority. When skin temperature drops low enough, ice crystals can form around and within the cells, robbing cells of needed water and possibly causing cell death.

These factors increase the risk for frostbite:

• Intoxication with alcohol or other substances
• Very young or very old age
• Cardiovascular disease
• Peripheral vascular disease (narrowing of blood vessels in extremities)
• Diabetes
• Psychiatric illness
• Exhaustion, hunger, malnutrition, or dehydration
• Winter sports, especially at high altitudes
• Outdoor work
• Homelessness
• Severe injury
• Smoking

Your healthcare provider will ask about your exposure to cold, including what the temperature was and how long you were exposed. He or she will also examine your skin, looking for signs of superficial and deep injury, the extent of which may not become apparent until the area rewarms. Blood tests and imaging studies, such as magnetic resonance imaging (MRI), may be needed to determine the severity of your injury as well as any complications, such as infection.

Take these steps to help prevent frostbite:

• Wear several layers of warm clothing that do not constrict movement and that provide protection from wind and water.
• Wear dry, warm gloves, socks, and insulated boots.
• Cover your head, preferably with earflaps in extreme conditions. Thirty percent of heat loss occurs through the head.
• Drink plenty of fluids and eat plenty of food during lengthy outings. Do not drink alcohol.
• Watch for the development of white patches on the face and ears of your companions. These may signal frostbite.

It's important to get conventional medical care as soon as possible for frostbite. Mild frostbite is treated by rewarming the affected area, washing it with an antiseptic, applying a sterile dressing, taking daily whirlpool baths, and resting in bed. If medical care is not available immediately, rewarm a mildly frostbitten area in a bath of warm water. It's important not to use hot water, fire, a household heater, or the like (unless warm water is not available) because these methods may burn the skin before the feeling returns. Remove any jewelry from the affected area before rewarming because the area may swell. Never rub or massage frozen body parts, and avoid walking on a frostbitten foot if possible.

Deep frostbite is treated by rapid thawing (only if there is no danger of refreezing) in a warm water bath. The patient should be hospitalized and have the frostbitten area elevated. Medication may be given to control pain. Healthcare providers will take steps to prevent or treat any infection. Twice-daily warm whirlpool baths with an aseptic solution are used until healing has occurred, which may take weeks to months. Cotton is often placed between affected toes or fingers to separate them and help them heal. Deep frostbite is often accompanied by hypothermia, a medical emergency that requires hospital care.

Your provider may prescribe drugs, such as narcotic analgesics to treat pain, nonsteroidal anti-inflammatory drugs (NSAIDs) to treat pain and inflammation, antibiotics to prevent or treat infection, or tetanus toxoid to prevent tetanus.

If frostbite has caused tissue death in any area, such as a hand or foot, the extremity or area may require amputation. Typically this decision is not made for several months, when the extent of the damage is more evident. (At first, frostbite may look worse than it is because the skin may be more seriously affected than the underlying tissues.) If, however, the person has serious infection, wet gangrene, or pain that won't respond to treatment, surgery may be required sooner. Some healthcare providers use a sympathectomy—surgery to remove a section of nerves—to decrease severe swelling, help save tissue, and forestall complications. Long-term benefits of this surgery have not been proven.

As stated, it is important to seek conventional care for frostbite as soon as possible to prevent serious tissue damage. While nutritional supplements may enhance conventional treatment, drinking fluids and eating plenty of food before and during exposure to cold remain the key to avoiding and treating frostbite because they help maintain the body's core temperature.

• Vitamin C

In a well-designed, controlled animal study, rats with frostbite were given oral vitamin C together with either a warm water bath (as used in conventional care) or a warm bath containing Indian black tea. Each of these groups did better than the rats that received only standard care (namely, a warm water bath alone), suggesting that vitamin C may be a good addition to standard, medical treatment of frostbite. In addition, the group that received oral vitamin C in combination with the Indian black tea baths did the best of the three. The ingredients in the black tea that may have contributed to the additional improvement are as follows:

• Quercetin – reduces frailty of blood vessels
• Caffeine – helps the blood vessels relax thereby increasing blood flow
• Theophylline – may enhance one's ability to generate body heat

When taken prior to cold exposure, the following fat-soluble antioxidants may help protect against development of frostbite or other cold-induced injuries:

• Vitamin E

• Cayanne pepper (Capsicum spp) in topical form has long been used traditionally in China and Japan to treat frostbite.
• Poplar buds (Populus spp. including P. nigra, P. canadensis, and P. tachamahaca), also known as balm of Gilead and balm of Mecca, may be used in mild cases of frostbite as an ointment or other topical formula (containing 20% to 30% bud exudate) to alleviate the pain and reduce the risk of infection associated with frostbite.

There have been few studies examining the effectiveness of specific homeopathic remedies. A professional homeopath, however, may recommend one or more of the following treatments for frostbite based on his or her knowledge and clinical experience. Before prescribing a remedy, homeopaths take into account a person's constitutional type. In homeopathic terms, a person's constitution is his or her physical, emotional, and intellectual makeup. An experienced homeopath assesses all of these factors when determining the most appropriate remedy for a particular individual.

• Agaricus — primary remedy for the burning, itching, redness, and swelling associated with frostbite
• Apis mellifica — for the burning or stinging sensation and redness associated with frostbite, particularly if there is excessive swelling; individuals who benefit from this remedy may also have a dull pain the back of the head 
• Carbo vegetabilis — for individuals who feel faint or who have difficulty breathing
• Lachesis — for frostbite with a blue or purple discoloration; the skin may bleed easily and irreversible tissue damage may result if it is not treated; this remedy is most appropriate for individuals who are restless and unsettled
• Silicea — for frostbite in thin, frail people who typically feel cold and tired; this remedy is most appropriate for individuals who have pus-filled wounds

Frostbitten areas should never be massaged or vigorously rubbed.

The outlook for frostbite depends on the depth of tissue injury and can range from complete recovery to amputation.

Possible complications of frostbite include the following:

• Increased sensitivity to cold
• Changed skin color
• Faulty nail growth in an affected hand or foot
• Profuse sweating
• Pain with use of the affected area
• Altered sensation in the affected area
• Arthritis
• Skin cancer

Because the damage caused by frostbite is not always immediately evident, healthcare providers will want to monitor your condition over weeks or even months to determine the severity of the injury.

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