Frostbite

Frostbite is an injury caused by freezing of the skin and underlying tissues. First your skin becomes very cold and red, then numb, hard and pale. Frostbite is most common on the fingers, toes, nose, ears, cheeks and chin. Exposed skin in cold, windy weather is most vulnerable to frostbite. But frostbite can occur on skin though that is covered by gloves or other clothing.

Frosting, the first stage of frostbite, doesn't cause permanent skin damage. You can treat very mild frostbite with first-aid measures, including re-warming your skin. All other frostbite requires medical attention because it can damage skin, tissues, muscle and bones. Possible complications of severe frostbite include infection and nerve damage.

Signs and symptoms of frostbite include:

  • At first, 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 re-warming in severe cases

Frostbite is most common on the fingers, toes, nose, ears, cheeks and chin. Because of 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 second stage of frostbite appears as reddened skin that turns white or pale. The skin may remain soft, but some ice crystals may form in the tissue. Your skin may begin to feel warm — a sign of serious skin involvement. If you treat frostbite with re-warming at this stage, the surface of your skin may appear mottled, blue or purple. And you may notice stinging, burning and swelling. A fluid-filled blister may appear 24 to 36 hours after re-warming the skin.

Severe (Deep) Frostbite: As frostbite progresses, it affects all layers of the skin, including the tissues that lie below. 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 re-warming. Afterward, the area turns black and hard as the tissue dies.

 Causes:

Frostbite occurs when skin and underlying tissues freeze. 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.

Specific conditions that lead to frostbite:

  • Wearing clothing that isn't suitable for the conditions you're in; for example, it doesn't protect against cold, windy or wet weather or it's too tight.
  • Staying out in the cold and wind too long. Risk increases as air temperature falls below 5 FH (-15*C), even with low wind speeds. In wind chill of -16.6 F (-27*C), frostbite can occur on exposed skin in less than 30 minutes.
  • Touching materials such as ice, cold packs or frozen metal.

Risk factors

The following factors increase the risk of frostbite:

  • Medical conditions that affect your ability to feel or respond to cold, such as dehydration, exhaustion, diabetes and poor blood flow in your limbs.
  • Alcohol or drug abuse.
  • Smoking.
  • Fear, panic or mental illness, if it inhibits good judgment or hampers your ability to respond to cold.
  • Previous frostbite or cold injury.
  • Being an infant or older adult, both of whom may have a harder time producing and retaining body heat.
  • Being at high altitude, which reduces the oxygen supply to your skin.

Prevention:

Here are some tips to help you stay safe and warm:

  • Limit time you're outdoors in cold, wet or windy weather.
  • Pay attention to weather forecasts and wind chill readings. In very cold, windy weather, exposed skin can develop frostbite even in a minute.
  • Dress in several layers of loose, warm clothing.
  •  Air trapped between the layers of clothing acts as insulation against the cold. Wear windproof and waterproof outer garments to protect against wind, snow and rain. Choose undergarments that wick moisture away from your skin. Change out of wet clothing — particularly gloves, hats and socks as soon as possible.
  • Wear a hat or headband that fully covers your ears.
  •  Heavy woolen or windproof materials make the best headwear to protect from cold.
  • Wear mittens rather than gloves.
  • Mittens provide better protection. Or try a thin pair of glove liners made of a wicking material (like polypropylene) under a pair of heavier gloves or mittens.
  • Wear socks and sock liners that fit well, wick moisture and provide insulation.
  • You might also try hand and foot warmers. Be sure the foot warmers don't make your boots too tight, restricting blood flow.
  • Watch for signs of frostbite.
  •  Early signs of frostbite include red or pale skin, prickling, and numbness.
  • Plan to protect yourself.
  • When traveling in cold weather, carry emergency supplies and warm clothing in case you become stuck. If you'll be in remote territory, tell others your route and expected return date.
  • Don't drink alcohol if you plan to be outdoors in cold weather.
  • Alcoholic beverages cause your body to lose heat faster.
  • Eat well-balanced meals and stay hydrated.
  •  Doing this even before you go out in the cold will help you stay warm. And if you do become cold, drinking warm, sweet beverages, such as hot chocolate, will help you warm up.
  • Keep moving.
  • Exercise can get the blood flowing and help you stay warm, but don't do it to the point of exhaustion.

Treatments and drugs:

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 frostbite requires 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. Wear cold protective clothes.

  • Gently re-warm frostbitten areas:

Deepen your hands or feet in warm water of 99 to 108 F (37 to 42* C) for 15 to 30 minutes. If a thermometer isn't available, test the water by placing an uninjured hand or elbow in it. It should feel very warm, not hot.

Don't re-warm frostbitten skin with direct heat, such as a stove, heat lamp, fireplace or heating pad. These can cause burns.

  • Don't soften the affected areas if it will freeze again:

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, Motrin IB, others) to reduce pain and inflammation.

  • Don't walk on frostbitten feet or toes if possible:

This further damages the tissues.

  • 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:

  • Re-warming the skin:

 If it hasn't been done already, your doctor will re-warm 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 re-warms.

  • Oral pain medicine:

Because the re-warming process can be painful, your doctor is likely to give you a drug to ease the pain.

  • 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 move gently 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 that helps restore blood flow (thrombolytic), such as tissue plasminogen activator (TPA). Studies of people with severe frostbite show that TPA lowers the risk of amputation. 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:

 Hyperbaric oxygen therapy involves breathing pure oxygen in a pressurized room. Some patients showed improved symptoms after this therapy. But more study is needed.