What is frostbite?

Frostbite is a freezing injury to the body's tissues caused by prolonged exposure to cold. It can cause lifelong (permanent) damage to the body. The most common places affected by frostbite are the fingers, toes, cheeks, chin, ears, and nose. Ice put directly on the skin and left too long can also lead to frostbite. 

What causes frostbite?

Frostbite is caused by exposure to cold temperature, often below 32°F (0°C). Intense cold can freeze the water in the body's cells. How severe the symptoms are depends on several things. These include air temperature, length of time in the cold, wind chill, dampness, and type of clothing worn.

Who is at risk for frostbite?

Frostbite can happen in minutes, or it can take hours. It depends on certain conditions and health problems you may have that put you at greater risk.

Some conditions may lead to an increased risk for frostbite, such as:

• Reduced blood circulation from health conditions, such as peripheral arterial disease (PAD), diabetes, peripheral neuropathy, or Raynaud disease

• Limited blood flow to the hands or feet due to gloves, boots, socks, or other clothing items that are too tight

• Not having the correct clothing to match the weather

• Windy conditions, which cause more rapid cooling of the skin and body

• Certain medicines, such as beta blockers

• Smoking

• Alcohol or drug intoxication that results in impaired sensitivity to the cold

What are the symptoms of frostbite?

The following are the most common symptoms of frostbite:

• Redness or pain in a skin area

• A white or grayish-yellow skin area

• Skin that feels abnormally firm or waxy

• Numbness

• Blisters (filled with clear fluid or possibly blood-filled in more severe cases)

• Black, dead skin and tissues (gangrene) in severe cases

In most cases, the person is unaware of frostbite because the frozen tissues are numb. The symptoms of frostbite may look like other health conditions or problems. Always check with your healthcare provider for a diagnosis.

How is frostbite diagnosed?

If there are symptoms of frostbite, seek medical care right away. Frostbite and hypothermia both occur when skin is exposed to cold and body temperature falls.

A healthcare provider will ask about your exposure to the cold, and look at symptoms, such as the condition of your skin. The provider will ask if you have a health condition that may put you at risk for frostbite. Tests you may have can include X-ray, bone scan, or MRI. These tests can help figure out the tissue damage (bone or muscle) and help guide treatment. You will also be checked for hypothermia. Hypothermia is a more serious health condition and needs emergency medical care.

How is frostbite treated?

With frostbite, body tissues become frozen. Permanent damage may happen if the affected area is not treated right away. If frostbite occurs, protect the person with the following recommendations and then get medical care:

• Get the person into a warm room as soon as possible. Take off any wet clothing.

• Cover the person or area in warm blankets.

• Don’t walk on frostbitten feet or toes to avoid more serious damage.

• Immerse the areas affected by frostbite into warm (not hot) water until normal skin color returns. Don’t soak the affected area too long (no more than 30 minutes).

• Warm the affected area using body heat. For example, placing frostbitten fingers in the armpit.

• Don’t rub or massage the affected area as this can cause further damage. Handle the area gently.

• Don’t use anything hot, such as a heating pad, stove, or furnace, to warm the affected area. These areas are numb and may burn easily due to a lack of sensation.

• Gently wash the frostbitten area, dry, wrap in sterile bandages, and keep it clean so it doesn’t get infected.

• Talk with the healthcare provider about using an oral antibiotic or topical ointment.

You can follow these same recommendations if you are the person with frostbite.

Refreezing of thawed tissue can make tissue damage worse. So it is very important not to try thawing frostbitten tissues unless it is certain that refreezing will not happen. Delay thawing frozen tissue until a safe and warm location can be reached. A frostbite condition most often goes away over a period of weeks or months.

Hospital treatment for frostbite is careful rewarming. This is done using warm water. During this process, the frostbitten part will start to throb. Pain medicine will likely be given to help make the process less painful. In severe cases, other medicines may be used. These include blood thinners (medicines that dissolve blood clots) and medicines that widen blood vessels to improve blood flow to the frostbitten area.

What are possible complications of frostbite?

The affected body part may throb for a few weeks to months. Tingling or feelings of electric shock may also be felt. There may be cold sensitivity, chronic numbness, chronic pain, and other symptoms that can last years. Other problems that can occur include infection and tetanus. You may need a tetanus shot.

Rewarmed tissue must be watched to see if it recovers. If tissue dies, a condition called gangrene can happen. Surgery may be needed to remove the dead tissue. In the most severe cases, amputation of an affected area may be needed to prevent spreading of gangrene.

How can frostbite be prevented?

To prevent frostbite, do the following in cold weather:

• Dress for the weather. Wear enough of the appropriate clothing layers to keep you warm and dry. Cover exposed body parts to protect them from the cold.

• Eat enough food.

• Don't drink alcohol and don't smoke. They make the skin more sensitive to cold.

• Try not to get wet.

• Carry emergency supplies when you are out in cold weather.

• If you use an ice pack, only use it for up to 15 minutes every 1 to 2 hours. To make an ice pack, put ice cubes in a plastic bag that seals at the top. Wrap the bag in a clean, thin towel or cloth. Never put ice or an ice pack directly on the skin.

• Watch for symptoms of frostbite, such as cold, prickly skin, numbness, skin color changes, or stiffness of body tissues.

When should I call 911?

Call 911 if you have:

• Body temperature below 95°F (35°C)

• Skin that is cold, numb, or tingly

• Skin that is blue, white, gray, or waxy

• Symptoms, such as confusion, memory loss, slurred speech, or slow and uncoordinated body movements

• Heartbeat changes

• Chest pain or trouble breathing

• Loss of consciousness

Key points about frostbite

• Frostbite is when body tissues become frozen due to prolonged exposure to cold.

• Symptoms include redness or pain, numbness, a white or grayish-yellow skin area, and skin that feels abnormally firm or waxy.

• The affected area should not be rubbed or massages. Don’t use anything hot, such as a heating pad, to warm the affected area. These areas are numb and may burn easily.

• Permanent damage may happen if the affected area is not treated right away.

• If tissue dies, a condition called gangrene can happen. You may need surgery to remove the dead tissue. Amputation may be needed in the most severe cases.