Frostbite amputations

Areas that are usually affected include cheeks, ears, nose, and fingers and toes. Frostbite is often preceded by frostnip. The symptoms of frostbite progress with prolonged exposure to cold. Historically, frostbite has been classified by degrees according to skin and sensation changes, similar to burn classifications. However, the degrees do not correspond to the amount of long term damage. A simplification of this system of classification is superficial (first or second degree) or deep injury (third or fourth degree).

Frostbite is an injury caused by freezing of the skin and underlying tissues

In the earliest stage of frostbite, known as frostnip, there is no permanent damage to skin. Symptoms include cold skin and a prickling feeling, followed by numbness and inflamed or discolored skin. As frostbite worsens, skin may become hard or waxy-looking.

Exposed skin in cold, windy weather is most vulnerable to frostbite, but it can affect skin covered by gloves or other clothing. You may not realize you have frostbite until someone else points it out.

You can treat frostnip by rewarming. All other frostbite requires medical attention because it can permanently damage skin, muscle, bone and other tissue.

At first, cold skin and a prickling feeling
Numbness
Skin that looks red, white, bluish-white, grayish-yellow, purplish, brown or ashen, depending on the severity of the condition and usual skin color
Hard or waxy-looking skin
Clumsiness due to joint and muscle stiffness
Blistering after rewarming, 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 points it out. Changes in the colour of the affected area might be difficult to see on brown or black skin.

Frostbite occurs in several stages:

Frostnip: Frostnip is a mild form of frostbite. Continued cold exposure leads to numbness in the affected area. As your skin warms, you may feel pain and tingling. Frostnip doesn’t cause permanent skin damage.

Superficial frostbite: Superficial frostbite causes slight changes in skin colour. The skin may begin to feel warm — a sign of serious skin involvement. If you treat frostbite with rewarming at this stage, the surface of the skin may appear mottled. And you may notice stinging, burning, and swelling. A fluid-filled blister may appear 12 to 36 hours after rewarming the skin.

Deep (severe) frostbite: As frostbite progresses, it affects all layers of the skin, as well as the tissues that lie below. The skin turns white or blue-gray, and you lose all sensation of cold, pain, or discomfort in the area. Joints or muscles may stop working. Large blisters form 24 to 48 hours after rewarming. The tissue turns black and hard as it 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 include:

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 F (minus 15 C), even with low wind speeds. In wind chill of minus 16.6 F (minus 27 C), frostbite can occur on exposed skin in less than 30 minutes.

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, excessive sweating, exhaustion, diabetes and poor blood flow in the limbs
Alcohol or drug use
Smoking
Fear, panic or mental illness that impairs your judgment
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, where there’s less oxygen

Complications

Complications of frostbite include:

Increased sensitivity to cold
Increased risk of developing frostbite again
Long-term numbness in the affected area
Excessive sweating (hyperhidrosis)
Changes in skin colour
Changes in or loss of nails
Joint stiffness (frostbite arthritis)
Growth problems in children, if frostbite damages a bone’s growth plate
Infection
Tetanus
Gangrene — decay and death of tissue resulting from an interruption of blood flow to the affected area — which can result in amputation
Hypothermia

Prevention

Frostbite can be prevented. Here are tips to help you stay safe and warm. Limit time 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 in a matter of minutes.

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 the skin. Change out of wet clothing — particularly gloves, hats, and socks — as soon as possible.

Wear a hat or headband that fully covers the ears. Heavy woolen or windproof materials make the best headwear for cold protection. Wear mittens rather than gloves. Mittens provide better protection. Or try a thin pair of glove liners made of a wicking material (such as polypropylene) under a pair of heavier gloves or mittens.

Wear socks and sock liners that fit well, wick moisture and provide insulation. Consider hand and foot warmers as well. Be sure foot warmers don’t make boots too tight, restricting blood flow.
Watch for signs of frostbite. Early signs of frostbite include changes in skin colour, prickling, and numbness. Seek warm shelter if you notice signs of frostbite.

Plan to protect yourself. When travelling in cold weather, carry emergency supplies and warm clothing in case you become stranded. 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 the 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. Keep moving. Exercise can get the blood flowing and help you stay warm, but don’t do it to the point of exhaustion.