Signs and Symptoms

The following are signs and symptoms of frostbite:

• Pain or prickling progressing to numbness
• Pale, hard, and cold skin with waxy appearance
• Flushing from 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 after exposure

What Causes It?

When exposed to cold, the body tries to preserve heat. Blood vessels near the skin's surface narrow, forcing more blood into the core to keep the heart and lungs warm. This helps prevent hypothermia, which results when the body's temperature falls below 98°F (34°C). However, it also prevents the extremities (such as hands and feet) from receiving enough warm blood. At first, the blood vessels alternate between narrowing and widening, to keep the extremities as warm as possible. But under extremely cold conditions, the vessels stop widening. When skin temperature drops low enough, ice crystals can form around and within the cells, freezing tissue and possibly rupturing cells. The lack of circulation that occurs when the body directs blood flow away from the extremities may also cause cell damage.

Who's Most At Risk?

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 the extremities)
• Poor circulation
• Taking beta-blockers
• Diabetes
• Hypothyroidism
• Exhaustion, hunger, malnutrition, or dehydration
• Winter sports, especially at high altitudes
• Outdoor work
• Windy and or wet weather
• Homelessness
• Severe injury
• Smoking
• Psychiatric conditions
• Previous frostbite
• Skin damage
• Constricting clothing and footwear

What to Expect at Your Provider's Office

Seek emergency medical care to treat frostbite as soon as possible. Your health care provider will ask about your exposure to cold, including what the temperature was and length of exposure. Your provider will also examine your skin, looking for signs of superficial and deep injury. You may not be able to see the extent of your injury until the area rewarms. Doctors may run blood tests and imaging studies, such as magnetic resonance imaging (MRI), to determine the severity of your injury, as well as any complications, such as infection.

Treatment Options

Prevention

If you are going to be outside in cold temperatures, it's essential to prevent frostbite. Take these steps to keep warm:

• Wear several layers of warm clothing that allow you to move while providing protection from wind and water.
• Wear dry, warm gloves, socks, and insulated boots. Hands and feet account for 90 percent of injuries.
• Replace wet clothes immediately.
• Cover your head, preferably with earflaps, in extreme conditions. About 30% of heat loss occurs through the head.
• Drink plenty of fluids and eat plenty of food during lengthy outings. Do not drink alcohol, smoke cigarettes, or drink caffeine.
• Watch for the development of white patches on the face and ears of your companions. These may signal frostbite.

Treatment Plan

Frostbite is a medical emergency. It is important to get conventional medical care as soon as possible. Remove constricting or wet clothing and immobilize and insulate the affected areas. Your health care provider will treat mild frostbite by rewarming the affected area, washing it with an antiseptic, and applying a sterile dressing. If medical care is not available immediately, seek shelter and rewarm a mildly frostbitten area by immersing it in warm water (98.6 to 102.24°F or 37 to 39°C), or by repeatedly applying warm cloths to the area for 30 minutes. Never use hot water, fire, a heating pad, or other dry heat 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 (however, if you are far from help, it is better to walk on frozen feet than to thaw them out). Wrap the area in dry dressings, putting dressings between fingers and toes to keep them separated. If there is any danger of refreezing, it is best not to thaw the area until you reach warm shelter. Thawing and refreezing can seriously damage tissue.

If there is no danger of refreezing, treat deep frostbite by rapid thawing in a warm water bath. The patient should be hospitalized and have a health care provider elevate the frostbitten area. Medication can help control pain. Providers will take steps to prevent or treat any infection. Deep frostbite is often accompanied by hypothermia, a medical emergency that requires hospital care.

Drug Therapies

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 a tetanus shot to prevent tetanus. Aspirin and ibuprofen may be helpful, but evidence is limited.

Surgical Procedures

Generally, surgical treatment is not used as an early intervention. However, it may be necessary in patients with compartment syndrome.

If frostbite has caused tissue death in any area, such as a hand or foot, amputation may be necessary. The decision to amputate is taken over a period of 4 to 8 weeks after the injury. However, in patients with serious infection, wet gangrene, or pain that won't respond to treatment, surgery may be required sooner.

Complementary and Alternative Therapies

It is important to seek conventional care for frostbite as soon as possible to prevent tissue damage. While nutritional supplements may enhance conventional treatment, maintaining the body's core temperature by dressing warmly, drinking fluids, and eating plenty of food before and during exposure to cold are critical to preventing and treating frostbite.

• Vitamin C -- One well-designed animal study suggested that vitamin C may have some beneficial effect on frostbite when combined with standard medical treatment.

You should never use herbs to self-treat frostbite. Speak to your physician before using any herbal therapies to make sure they are right for you, and that they do not interfere with conventional treatment.

• Aloe vera in topical form improves tissue survival in animal studies. However, no human studies exist to support topical aloe application to treat frostbite.

Few studies have examined the effectiveness of specific homeopathic remedies. A homeopath, however, may recommend one or more of the following treatments for frostbite:

• Agaricus
• Apis mellifica
• Carbo vegetabilis
• Lachesis
• Silicea

Frostbitten areas should never be massaged or vigorously rubbed.

Prognosis/Possible Complications

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

A majority of patients have long-term, residual symptoms including pain, loss of sensation, swelling, hair or nail deformities, and rarely, arthritis.

Following Up

Damage caused by frostbite is not always immediately evident.  Health care providers will monitor your condition over weeks or months to determine the severity of your injury. Many patients have long-term symptoms, including pain, numbness, swelling, and hair or nail deformities.

Supporting Research

Feily A, Namazi MR. Aloe vera in dermatology: a brief review. G Ital Dermatol Venereol. 2009;144(1):85-91. PMID: 19218914 www.ncbi.nlm.nih.gov/pubmed/19218914.

Freer L, Handford C, Imray CHE. Frostbite. In: Auerbach PS, Cushing TA, Harris NS, eds. Auerbach's Wilderness Medicine. 7th ed. Philadelphia, PA: Elsevier; 2017:chap 9.

Grieve A, Davis P, Dhillon S, Richards P, Hillebrandt D, Imray C. A clinical review of the management of frostbite. J R Army Med Corps. 2011:157(1):73-78. PMID: 21465915 www.ncbi.nlm.nih.gov/pubmed/21465915.

Johnson MP. Frostbite. In: Ferri FF, ed. Ferri's Clinical Advisor 2018. Philadelphia, PA: Elsevier; 2018:502-503.e1.

Kemper TC, de Jong VM, Anema HA, van den Brink A, van Hulst RA. Frostbite of both first digits of the foot treated with delayed hyperbaric oxygen: a case report and review of literature. Undersea Hyperb Med. 2014;41(1):65-70. PMID: 24649719 www.ncbi.nlm.nih.gov/pubmed/24649719.

McIntosh S, Hamonko M, Freer L, et al. Wilderness medical society practice guidelines for the prevention and treatment of frostbite. Wilderness Environ Med. 2011;22(2):156-166. PMID: 21664561 www.ncbi.nlm.nih.gov/pubmed/21664561.

Movchan K, Kovalenko A, Zinov'ev E, Shutkin A, Sidorenko V, Donskov V. Experience with surgical necrectomy for deep frostbite using physical means to influence the tissue. Vestn Khir Im I I Grek. 2011;170(1):36-40. PMID: 21506352 www.ncbi.nlm.nih.gov/pubmed/21506352.

Murray MT. Aloe vera (Cape aloe). In: Pizzorno JE, Murray MT, eds. Textbook of Natural Medicine. 4th ed. Elsevier Churchill Livingstone; 2013:chap. 64.

Sawka MN, O'connor FG. Disorders due to heat and cold. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 109.

Zafren K, Danzl DF. Frostbite and nonfreezing cold injuries. In: Walls RM, Hockberger RS, and Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 131.