Frostbite occurs when the skin is exposed to extreme or prolonged cold. The skin freezes, as do tissues beneath the surface of the skin. In extreme cases, muscle, nerves, and blood vessels may also freeze.
Skin may freeze within minutes when exposed to temperatures that fall below freezing. Even if temperatures are above freezing, the skin is likely to freeze if it’s wet or exposed to severe wind chills.
Frostbite also occurs when your skin directly contacts very cold surfaces. This type of exposure may immediately freeze the skin that touches the frozen surface.
You’re more likely to suffer frostbite when exposed to cold weather under any of the following circumstances:
- you’re not appropriately dressed for freezing conditions
- your body is weakened due to fatigue, hunger, dehydration, physical labor, injury, or alcohol consumption
- you smoke (smoking narrows blood vessels and slows down circulation, allowing frostbite to advance more rapidly)
- you suffer from medical conditions such as diabetes, depression, cardiovascular disease, or peripheral vascular disease (these conditions may weaken your ability to notice and appropriately respond to the cold)
- you take beta-blocker medications
Young children and the elderly are also more likely to suffer from frostbite.
Most cases of frostbite include the following symptoms:
- skin feels prickly and/or numb
- skin is discolored (red, white, gray, or yellow)
- pain around the exposed area
Frostbite is severe when the following symptoms emerge:
- blisters on the skin
- skin turns black
- joints and muscles are stiff or not functioning
Regardless of the severity of frostbite, seek medical care if you have frostbite and any of the following:
- swelling, redness, or discharge in the frostbitten area
Most cases of frostbite are diagnosed based on a physical exam, and your description of where, when, and how the frostbite occurred. If frostbite is severe, X-rays or bone scans may be used to assess damage to bone and muscle.
For immediate first aid treatment, do the following:
- Seek shelter from the cold.
- Warm your hands by tucking them under your arms.
- If possible, go indoors and remove wet clothing and jewelry.
- Once inside, place your hands and feet in warm water, and cover the rest of your body with a blanket.
- Avoid sources of heat such as lamps, fire, or heating pads. These can burn frostbitten skin.
- If you think you’re dehydrated, drink warm drinks.
- See a doctor as soon as possible.
You can treat most cases of frostbite by warming the affected areas in water. A doctor will also sterilize the affected skin and wrap it in dressings. When skin is raw from frostbite, you're prone to getting an infection. If your skin is infected, your doctor may prescribe antibiotics.
In the most extreme cases, bone, muscle, and nerves experience damage. Amputation surgery may be necessary. Doctors may try to repair tissues with drugs called thrombolytics, which they’ll deliver intravenously (through a vein). These drugs can cause severe bleeding, and are usually a last resort to avoid amputation.
Your body’s natural response to extreme cold is to direct blood to your heart and lungs. Keeping these organs warm prevents hypothermia. Hypothermia occurs when your body can't produce enough heat to protect itself from the cold.
You should treat hypothermia before treating frostbite. While frostbite is painful and can result in permanent damage to exposed areas, hypothermia is a more serious cold weather threat. Frostbite on your arms and legs can indicate hypothermia because it takes a while for frostbite to spread that far. Frostbite usually occurs on your toes, nose, cheeks, ears, and chin.
The best thing you can do to prevent frostbite is to dress appropriately for severe weather. Be aware of weather forecasts before you go out. Don’t plan to spend an extended amount of time outside when the weather is below freezing. Avoid going outside when temperatures fall below 0ºF.
If you plan to be outside in cold weather, wear multiple layers of clothing. Be sure that none of your skin is exposed. Your clothing should be loose-fitting and waterproof.
Sometimes, you can’t anticipate frostbite. You never know when your car will break down. For that reason, it's good to keep an emergency kit handy with blankets, gloves, hats, and nonperishable snacks. Being prepared helps you stay protected.