Extreme cold can cause a range of injuries and conditions, including frostnip, chilblains, frostbite, hypothermia, and trench foot. Frostnip is the early stages of frostbite.
What is frostbite?
When it is very cold, or if a person is exposed to the cold for a long time, blood flow to some parts of the body, for example the fingers and hands, can drop to dangerously low levels. When there is not enough oxygen-rich blood going to the affected areas, this can lead to tissue cell death.
People who spend a long time in the cold are at risk of frostbite.
At freezing point, 0 degrees Celsius or 32 degrees Fahrenheit, pain associated frostnip can happen after several seconds. Wet conditions can make it worse.
If temperatures drop to freezing, the blood vessels that are near to the surface of any exposed skin start to narrow, or constrict. This is because they are trying to keep the core, or center, of the body warm.
As circulation decreases, tiny blood clots may appear. The tissues and fluids in the affected part can freeze, and this can cause the soft tissue to die. Gangrene may result, and amputation may be necessary. The damage from frostbite can be serious and long lasting.
Any part of the body can be affected by frostbite, but it usually happens on the hands, ears, feet, nose and lips.
What are the symptoms of frostbite?
Like burns, frostbite can be categorized in degrees, depending on how severe it is.
First-degree frostbite, or frostnip, only affects the surface of the skin.
Early symptoms are pain and itching. The skin then develops white or yellow patches, and it may become numb. Frostnip does not usually cause permanent damage because only the top surface of the skin is affected, but the affected areas may be insensitive to heat and cold for a while.
Second-degree frostbite may cause the skin to freeze and become hardened, but it does not affect the deep tissues.
After 2 days, purple-colored blisters may appear in areas that were frozen. These blisters may turn black and become hardened. It can take 3 to 4 weeks for the lesions to heal.
If there is nerve damage, there will be numbness, pain and even total loss of feeling.The decreased sense of heat and cold may be permanent.
Third- and fourth-degree frostbite is when it penetrates deeper, causing deep tissue injury.
Muscles, blood vessels, nerves, and tendons freeze. The skin feels smooth and waxy. The patient may lose the use of an extremity, for example a foot or a hand. In some cases, this is permanent.
Complications of frostbite
In extreme cases, gangrene might result, and it may be necessary to amputate the affected areas, such as fingers or toes. If the finger or toe or other part is not amputated, and it is not treated, this may lead to disease within the body and even threaten a person's life.
Frostbite can lead to systemic disease, such as disseminated intravascular coagulation (DIC), in which small blood clots form in the blood vessels. Cardiovascular collapse and sepsis can also occur. All of these conditions can be fatal.
What is the treatment for frostbite?
Treatment focuses on warming or thawing the affected area. However, rubbing or massaging an area to re-warm soft tissue that has been damaged by third- and fourth-degree frostbite can sometimes lead to more tissue damage.
The affected person should move from the cold place to a warm one immediately. They must remove all wet clothes and replace them with dry ones. Covering the patient with blankets will help to keep them warm and make sure the frostbitten parts are protected.
Warming should be gradual. The patient can put the affected parts in warm water until normal color returns. The affected parts may go red and become swollen when the circulation comes back. When the color returns, the affected areas can be removed from the warm water.
Direct heat, such as a fire, should be avoided. The frostbitten areas may not be able to detect high temperatures, and the patient may burn themselves without realizing.
After removing the areas from warm water, they should be dried gently. A sterile dressing can be put loosely over them to protect them. If there is any infection in the skin or blisters, the doctor may prescribe an antibiotic.
Who is at risk of frostbite?
People who spend a lot of time outside in cold weather are at risk of frostbite and other cold injuries. Young children, older people and those who are homeless are particularly susceptible.
Extreme cold at altitude increases the risk of frostbite.
Factors that increase the chance of frostbite include:
- Medical conditions such as exhaustion, dehydration, circulatory problems, diabetes, hunger and malnutrition
- Mental illness, panic or fear, because these may affect how the person responds to the cold
- Cigarettes, alcohol, or drug abuse
- Some medications, for example, beta blockers
- Previous cold injury or frostbite
- Age, because infants and older people may have more difficulty retaining body heat
- Wearing constrictive clothing or footwear
- Being out in wet and windy weather
- Spending time at high altitude, because of low temperatures and low oxygen levels.
People with a 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 of having severe symptoms.
How can people prevent frostbite?
Anyone planning to spend a lot of time outside in the cold will need appropriate, warm and waterproof clothing. Those working or practicing sports outside during severe winter weather must prepare well to avoid frostbite and other cold injuries.
If it is not possible to avoid spending time outside in extreme cold, the following measures can help to reduce the risk:
- Wearing adequate clothing, preferably in layers, as this traps the warm air inside
- Using a waterproof outer layer
- Using oxygen at altitudes of around 10,000 feet or above, to increase perfusion, or blood flow
- Being aware of symptoms, such as redness, tingling, numbness, pins and needles, and pain.
If a person starts to show symptoms of frostbite, they should seek medical attention.