What Is Frostbite? What Causes Frostbite? What Is Congelatio?

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Main Category: Dermatology
Also Included In: Blood / Hematology
Article Date: 05 Oct 2009 - 0:00 PDT

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When the skin and surrounding tissues are directly exposed to low temperatures, they can freeze and frostbite occurs. The medical term for frostbite is congelatio. The general term is 'cold injury', but 'frostbite' is commonly used by doctors. It can happen to anyone who is exposed to temperatures below freezing for an extensive amount of time, and without sufficient protection to keep the person warm at all times.

Individuals practicing outdoor sports, such as climbing, hiking, skiing and sailing are particularly at risk of getting frostbite, since they are regularly exposed to longer periods in outdoor extreme cold weather.

Frostbite typically affects parts of the body that are located far from the heart. The body extremities, such as the fingers, toes, nose, ears and penis are most likely to be affected.

The damage to the skin and tissue is caused by the creation of ice crystals. They swell, causing cells to rupture.

Damage to tissue is also caused by the shutting down of arteries and blood vessels that transport critical oxygen and blood supply to the affected areas.

The extent of frostbite differs depending on the length of exposure to the cold weather, and how badly damaged the tissues are. The injury will be considered superficial if only the skin and surface tissues are affected, and it is likely that the affected person will recover fully. On the other hand, if the blood vessels are affected, the damage is more likely to be permanent. If gangrene (dead tissue) occurs, even amputation may be considered indispensable.

Risks from frostbite

Anyone who spends long periods outdoors and is exposed to extremely cold temperatures can be at high risk of getting frostbite. Individuals who know they are going to be exposed to below-freezing temperatures should make sure they are well protected - this means wearing appropriate clothing.

Young children and elderly people are more vulnerable to frostbite because their bodies are not as efficient at controlling body temperature.

People with delicate medical conditions will have an increased risk of getting frostbite, especially those suffering diabetes or Raynaud's syndrome, which cause blood vessel damage or circulation problems. This is also the case if a person is taking certain medicines, such as beta-blockers. Those who have poor health due to smoking, drinking alcohol, or eating high-fat diets, are also more likely to get frostbite when exposed to sub-zero temperatures.

What are the signs and symptoms of frostbite

Research studies have shown that at zero degrees Celsius (32 Fahrenheit) or below, blood vessels that are close to the skin tissue of the extremities react to the low temperatures by contracting in order to help conserve interior body temperatures. However, the if period of exposure is longer than what the body is either used to or prepared for, three potential stages of frostbite may develop.

Frostbite can happen very quickly. Everybody should be aware and alert to the signs and symptoms. Because intense cold has an anesthetizing effect (numbing effect), the skin and tissue may freeze without the person realizing it. Therefore, it is vital to recognize the tingling sensation of frostnip that occurs on the first stage in order to take steps to treat the affected area before more severe symptoms build up.

• First degree frostbite
  
  First degree frostbite, also called frostnip, causes skin to appear yellow or white and feel cold to the touch. Slight burning sensations may be felt as well as other discomforts, such as tingling, soreness or aching in the affected area. Considering all these symptoms, this first stage of frostbite is relatively moderate and can easily be reversed by the gradual warming of the affected area.


• Second degree frostbite
  
  Second degree frostbite develops after a continued and prolonged exposure in cold weather.
  
  In this stage the disappearance of pain and reddening and swelling of the skin is noticeable.
  
  The affected area will become white, numb, and hard, and when the tissue is thawed out, the skin will turn red with exposed and painful blisters.
  
  Swelling and itching will also be felt during the process of warming and thawing of the affected areas. More severe tissue damage will likely occur.
  
  Treatment in this stage may consist of curing blisters and also peeling of the skin.


• Third degree frostbite
  
  Third degree frostbite is extremely dangerous.
  
  The skin will feel waxy and stiff, and tissues will feel frozen or wooden. There may also be damage to tendons, muscles, nerves and bones It is at this stage that the skin. This may occur as a result of the lack of blood circulation to the affected areas.
  
  If third degree frostbite is not treated immediately the damage most likely will become permanent, nerve damage will occur due to oxygen deprivation and all feeling is lost. Frostbitten areas will become discolored, purplish at first, and soon turn black. This is known as gangrene. If gangrene occurs, the affected body part will usually have to be amputated.

Treating frostbite

Preventing frostbite, by taking the necessary precautions, should always be a priority.

However, if frostbite does occur, it is imperative to seek medical attention immediately.

If medical assistance is not available, there are several steps that can be taken to treat frostbite:

• Movement
  
  If the fingers and toes are affected, moving them will help improve circulation, if it is possible to do so. However, the affected area should not be rubbed or massaged. It is important to remove any wet clothes, and keep the body as warm as possible.


• Reheating
  
  The affected areas need to be re-warmed if frostbite is suspected. Warming a frostbitten area of the body can be very painful and preferably should be performed under medical supervision. However in an isolated location, it may not be possible to get medical assistance.
  
  If there is a possible risk of frostbitten areas refreezing, they should not be re-warmed. If they refreeze, they may become permanently damaged. If there is no risk of refreezing, the affected area should be re-warmed slowly for approximately half an hour. This can be done by immersing the area in lukewarm but not hot water.
  
  As the affected area progressively starts to warm, its normal color should begin to come back. The area can be removed from the water once it starts to appear red and swollen. If warm water is not available, softly wrap the person in blankets, or a sleeping bag. Also, another person's body heat can be used to warm the affected person.
  
  It is essential to never re-warm frostbitten skin using direct heat, such as a fire or hot water bottle. The lack of sensation in the skin may cause it to burn.


• Following reheating
  
  The area should be used as little as possible after it has been thawed. It is imperative to keep the skin clean and to avoid infection. The area should be wrapped in clean bandages. Fingers and toes should be wrapped separately. After recovery, the skin of the area will be discolored and will blister. The blisters should be bandaged in a sterile dressing.
  
  When frostbite is superficial, new pink skin regenerates underneath the discolored skin. Typically, within six months the area will be healed. However, some people have lasting problems. These can include pain, numbness and stiffness in the affected area. In some cases, rehabilitation using physical therapy (UK: physiotherapy) can improve circulation.
  
  In the case of severe frostbite, gangrene can develop in the affected area. It will turn a blue or black color. The damage is then permanent. The affected body part will usually require amputation.

How can you prevent frostbite?

Frostbite can occur extremely rapidly at temperatures below freezing. It is essential to take basic measures to guarantee that the skin is properly protected. Don't forget the wind-chill factor (chill factor), which can heighten the effects of frostbite and the velocity of its progression.

Extremities, which are the most vulnerable areas and the first to be affected, must be very well protected. If exposed to sub-zero temperatures for any length of time, a warm hat that protects the head and ears is indispensable, as a significant proportion of body heat is lost through the head. Gloves, or mittens, thick socks, and well insulated boots are essential.

Clothes should always fit well (not too tight or loose). Wearing a number of thin layers is more effective than wearing just a few thick ones. This is because thin layers trap air that warms to the body's temperature and acts as additional insulation. To prevent local pressure and constraint, make certain that each layer of clothing is larger than the one below.

If you work in a chemical laboratory remember than even brief exposure to liquid nitrogen and other cryogenic liquids can cause frostbite - wearing gloves and protective gear is vital.

If you get caught in a severe snowstorm or some outdoor situation where temperatures are very low you should seek shelter as soon as possible. A small cave, ditch, hollow tree or vehicle can help significantly reduce the risk of frostbite, especially if conditions are windy. Physically move your body to keep it warm, especially your hands and feet. If your hands are not adequately protected keep them inside your clothing, next to your body to keep them as warm as possible. Protect your face and nose.

Written by Stephanie Brunner M.A.
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today