FROSTBITE

Frostbite is an injury caused by freezing of the skin and underlying tissues. It causes the skin to become very cold and red, then numb, hard and pale. The most common cause of frostbite is exposure to cold-weather conditions. But it can also be caused by direct contact with ice, freezing metals or very cold liquids.

Frostbite usually affects the fingers, toes, nose, ears, cheeks and chin. Exposed skin in cold, windy weather is most vulnerable to frostbite, although frostbite can occur on skin covered by gloves or other clothing. Frostbite requires medical attention because it can damage skin, tissues, muscle and bones. Possible complications of severe frostbite include infection and nerve damage, which may require amputation.

Signs and symptoms of frostbite include:

  • Initially, cold skin and a prickling feeling
  • Numbness
  • Red, white, bluish-white or grayish-yellow skin
  • Hard or waxy-looking skin
  • Clumsiness due to joint and muscle stiffness
  • Blistering after rewarming, in severe cases

Because frostbite causes skin numbness, you may not realize you have frostbite until someone else points it out.

Frostbite occurs in several stages:

  • Frostnip. The first stage of frostbite is frostnip. With this mild form of frostbite, your skin pales or turns red and feels very cold. Continued exposure leads to prickling and numbness in the affected area. As your skin warms, you may feel pain and tingling. Frostnip doesn’t permanently damage the skin.
  • Superficial frostbite. The reddened skin turns white or pale. The skin may remain soft, but ice crystals may form in the tissue. Your skin may begin to feel warm—a sign of serious damage. If you treat frostbite with rewarming at this stage, the surface of your skin may appear mottled, blue or purple. You may notice stinging, burning and swelling. A fluid-filled blister may appear 24 to 36 hours after rewarming the skin.
  • Severe (deep) frostbite. As frostbite progresses, it affects all layers of the skin, including underlying tissues. You may experience numbness, losing all sensation of cold, pain or discomfort in the affected area. Joints or muscles may no longer work. Large blisters form 24 to 48 hours after rewarming. The area subsequently turns black and hard as the tissue dies.

Seek medical attention for frostbite if you experience:

  • Signs and symptoms of superficial or deep frostbite—such as white or pale skin, numbness, or blisters
  • Increased pain, swelling, redness or discharge in the area that was frostbitten
  • Fever
  • New, unexplained symptoms

Get emergency medical help if you suspect hypothermia, a condition in which your body loses heat faster than it can be generated. Signs and symptoms of hypothermia include:

  • Intense shivering
  • Slurred speech
  • Drowsiness and loss of coordination

DIAGNOSIS

The diagnosis of frostbite is usually apparent based on your signs and symptoms, appearance of your skin, and recent exposure to cold.

Your doctor may conduct tests, such as an X-ray, bone scan or magnetic resonance imaging (MRI) test, to determine frostbite severity and bone or muscle damage. Your doctor may also run tests if he or she suspects you have hypothermia, a condition that often occurs with frostbite.

 

RECOMMENDED MEDICATIONS

Treatment for frostbite includes first-aid care and medical treatment, depending on the severity of the frostbite. You can treat very mild frostbite (frostnip) with first-aid measures. All other forms of frostbite require prompt medical attention.

First-aid care

  • Check for hypothermia. Get emergency medical help if you suspect hypothermia.
  • Protect your skin from further exposure. If you’re outside, warm frostbitten hands by tucking them into your armpits. Protect your face, nose and ears by covering them with dry, gloved hands. Don’t rub the affected area and never rub snow on frostbitten skin.
  • Get out of the cold. Once you’re indoors, remove wet clothes.
  • Gently rewarm frostbitten areas. Soak hands or feet in warm water (37ºC to 42ºC) for 15 to 30 minutes. If a thermometer isn’t available, test the water by placing an uninjured hand or elbow in it. The water should feel warm, not hot.

Don’t rewarm frostbitten skin with direct heat, such as a stove, heat lamp, fireplace or heating pad. These can cause burns.

  • If there’s any chance the affected areas will freeze again, don’t thaw them. If they’re already thawed, wrap them up so that they don’t refreeze.
  • Take pain medicine. If you are in pain, take over-the-counter ibuprofen (Advil, others) to reduce pain and inflammation.
  • Don’t walk on frostbitten feet or toes if possible. This further damages the tissue.
  • Know what to expect as skin thaws. If the skin turns red and you feel tingling and burning as it warms, normal blood flow is returning. But seek emergency medical attention if the numbness or pain remains during warming or if blisters develop.

Medical treatment

  • Rewarming of the skin. If it hasn’t been done already, your doctor will rewarm the area using a warm-water bath for 15 to 30 minutes. The skin may turn soft and look red or purple. You may be encouraged to gently move the affected area as it rewarms.
  • Oral pain medicine. Because the rewarming process can be painful, your doctor will likely give you pain medications.
  • Protecting the injury. Once your skin thaws, your doctor may loosely wrap the area with sterile sheets, towels or dressings to protect the skin. You may need a brace or splint if the bone or muscle is involved. And you may need to elevate the affected area to reduce swelling.
  • Removal of damaged tissue (debridement). To heal properly, frostbitten skin needs to be free of damaged, dead or infected tissue. To better distinguish between healthy and dead tissue, your doctor may wait one to three months before removing damaged tissue.
  • Whirlpool therapy. Soaking in a whirlpool bath (hydrotherapy) can aid healing by keeping skin clean and naturally removing dead tissue. You’ll be encouraged to gently move the affected area while it is under water.
  • Infection-fighting drugs. If your skin or blisters appear infected, your doctor may prescribe oral antibiotics.
  • Clot-busting drugs. You may receive an intravenous injection (IV) of a drug (thrombolytic) that helps restore blood flow, such as tissue plasminogen activator (TPA). Studies show that TPA lowers the risk of amputation in people with severe frostbite. But these drugs can cause serious bleeding and are typically used only in the most serious situations and within 24 hours of exposure.
  • Wound therapy. If you have a complex wound, your doctor might suggest a technique called vacuum-assisted closure therapy to promote healing.
  • Surgery. In severe cases, surgery or amputation may be necessary to remove the dead or decaying tissue.
  • Hyperbaric oxygen therapy involves breathing pure oxygen in a pressurized room. Some patients showed improved symptoms after this therapy. But more study on hyperbaric oxygen therapy is needed.

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