What Is Frostbite (Congelatio)? What Causes Frostbite?

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

email to a friend   printer friendly   opinions  

Frostbite, also known as congelatio is a type of cold injury, and occurs when extreme cold causes localized damage to skin and other tissues - the fluid in the cells of the skin and other tissues freeze, resulting in blood clots in blood vessels, which reduce the supply of essential oxygen to tissues. Frostnip refers to the initial stages of frostbite.

Cold injuries - refers to several conditions caused by extreme cold, such as frostnip, chilblains, frostbite, hypothermia and trench foot.

If temperatures drop to freezing, the blood vessels close to exposed skin start to narrow (constrict) in an attempt to keep the core of the body warm. When it is very cold, or exposure to cold is prolonged, blood flow to some parts of the body, for example the fingers and hands, can drop to dangerously low levels - lack of oxygen-rich blood to the affected area(s) can lead to tissue cell death.

Any part of the body can be affected by frostbite. Most typically, people have it on their hands, ears, feet, nose and lips.

According to Medilexicon's medical dictionary:

Frostbite is Local tissue destruction resulting from exposure to extreme cold; in mild cases, it results in superficial, reversible freezing followed by erythema and slight pain (frostnip); in severe cases, it can be painless or paresthetic and result in blistering, persistent edema, and gangrene. Frostbite is currently treated by rapid rewarming.

Individuals who stay outdoors in the cold for prolonged periods are at risk of developing frostbite. Proper clothing, and if possible reducing length of exposure to the cold can help reduce the risk.

Experts say that young children and elderly people need to be especially careful.

People with some kind of medical condition that affects blood vessels and circulation should be extra careful to protect themselves against frostbite. Some medications, such as beta-blockers may increase the risk of getting frostbite and having severe symptoms.

What are the signs and symptoms of frostbite

A symptom is something the patient senses and describes, while a sign is something other people, such as the doctor notice. For example, drowsiness may be a symptom while dilated pupils may be a sign.

First Degree Frostbite - often called frostnip which only affects the surface of the skin. Initially there is some pain and itching. The skin develops white and/or yellow patches and may become numb.

Frostnip does not usually lead to any permanent damage because only the top surface of the skin is affected. The affected areas of the patient's skin may be especially sensitive for a while.

Second Degree Frostbite - the skin may freeze and become hardened. However, deep tissues are not affected. After a couple of days blisters may appear in areas that were frozen. These blisters may turn black and become hardened. Within three to four weeks the lesions heal. The patient may have especially sensitive skin in the affected areas - this sensitivity may persist for a long time.

Third and Fourth Degree Frostbite - the freezing penetrates deeper, and deep frostbite occurs. Muscles, blood vessels, nerves and tendons freeze. The skin feels extremely smooth and waxy. The patient may lose the use of, for example a foot or hand - this may be temporary or permanent.

Purple-colored blister appear, which eventually go black. If there is nerve damage there will be numbness, pain and even total loss of feeling.

In extreme cases the affected areas, such as fingers or toes may need to be amputated if there is gangrene. Even if amputation is not performed and the areas are left untreated, most likely the fingers or toes will eventually fall off.

Treating frostbite

Treatment focuses on warming or thawing the affected tissue. It is important to avoid refreezing after thawing, because of the risk of even further damage. Initially, if crystals have formed, the patient should avoid moving the affected area, as this may cause further damage.

The affected person should more from the cold to a warm environment immediately. All wet clothing must be taken off and replaced with dry clothes. If necessary, place blankets over the patient to keep them warm and make sure the frostbitten parts are protected.

If possible, rewarming should be done under the supervision of a trained health care professional. Warming should be gradual. Warm water (not hot) is ideal. Place the affected areas in warm water until normal color returns - it is not uncommon for the affected areas to go red and become swollen when circulation comes back. As soon as color has returned the affected areas can be removed from the warm water.

Direct heat, such as a fire should be avoided. The areas have probably lost their ability to detect high temperatures and the patient is at risk of unwittingly burning himself/herself.

The affected areas should not be rubbed - this may cause further damage.

After removing the areas from warm water, dry them gently, and if possible apply a sterile dressing loosely over them to protect them.

Infection - if there is infection in the skin or blisters, the doctor may prescribe an antibiotic.

How can you prevent frostbite?

• Wear adequate clothing. Experts say several layers of clothing which trap warm air inside is ideal.
• Make sure the outer layer of clothing is waterproof.
• If temperatures are extremely low, try spending less time exposed to it.
• Make sure your calorie intake is adequate (which should be higher in extreme cold).
• If you are at high altitude, for example climbing a mountain, take oxygen with you. The use of oxygen will reduce the risk.
• Look out for frostbite signs and symptoms - such as redness, tingling, numbness, pins and needles, and pain.

Written by Christian Nordqvist
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

• Additional
• References
• Citations