Frostbite, is a phenomenon that can occur in extreme cold: at temperatures lower than -15°C this phenomenon can occur quickly, but there is also a danger at higher temperatures. Protruding body parts such as nose, ears, fingers and toes can be damaged by the frost.
Frostbite is defined as the damage sustained by tissues while
subject to temperatures below their freezing point (typically
−0.55°C); in the broader sense it can include non-freezing
cold injuries, where tissues do not freeze but are subject to a
sustained and injurious cooling.
Hallam, M. J., Cubison, T., Dheansa, B., & Imray, C. (2010). Managing frostbite. Bmj, 341.
These parts of the body have few muscles (that generate and distribute body heat) and are located well away from the heart, so that less blood flows through the tissue. Due to the low temperatures, the blood vessels constrict, so that even less blood can reach these parts of the body. When combined with
thicker blood, for example due to elevaton, the risk of frostbite increases.
What causes frostbite?
The main cause is of course frost: it must be freezing to be able to speak of frostbite. There are a number of reinforcing factors:
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- Wind: when the wind blows harder, more heat can be removed from the body. As a result, the body and the aforementioned body parts cool down faster and further. This significantly increases the risk of frostbite.
- Altitude: At high altitudes, the body makes extra red blood cells in response to the lower amount of oxygen in the air. This makes the blood more viscous and it flows less easily through the blood vessels. In combination with the aforementioned narrowing of the blood vessels due to the low temperatures, this can lead to a rapid onset of frostbite.
- Smoking: Smoking constricts the blood vessels and makes them less flexible. This increases the chance of frostbite. High cholesterol can also lead to similar problems.
- Wet clothes: Wet clothes promote the release of heat to the environment and therefore cool a body faster.
- Poor blood circulation: Wearing tight clothing restricts blood circulation.
Recognizing (early symptoms of) frostbite
There are several stages in frostbite. Most people in temperate and colder climates have already experienced the first phase themselves: the skin turns white and starts to tingle. We already notice this when, for example, we cycle through the rain at a temperature just above 0°C: there is a lot of wind (wind due to riding a bicycle, even when there is no ambient wind) and the wet hands lose heat quickly. When we cycle for a long time it really hurts and the hands become numb and red: the
second phase has been reached. This is particularly painful when the bloodflow is restored.
When the hands cool even further (to below 0°C) you enter the
third phase: the tissue is damaged and nerves can die. Treatment must follow immediately, otherwise
dry gangrene will develop or
necrosis. This is the death of tissue by freezing. The skin turns black and dies. It may be necessary to
amputate body parts.
Other issues caused by cold weather
Besides freezing, there are other examples of damage that can be caused by low temperatures. An example of this is
chilblains. The toes or fingers swell and itch quite a bit. However, it is quite harmless and usually not chronic. By putting on the right clothing, the most important preventive measures have often already been taken.
A more serious condition is
trench feet. Trench feet became famous during the First World War, when tens of thousands of soldiers stood in the wet trenches day after day with their wet boots. Feet turn red or blue, swell and show blisters and open wounds. In fact, the feet begin to rot while still attached to the body. Gangrene can develop and the feet often have to be amputated to prevent death. Unlike
frostbite, for trench feet it doesn’t have to freeze: temperatures
below 16°C are low enough to lead to trench feet.
Treating frostbite
Below options come / are paraphrased from the academic book “
Handford, C., Thomas, O., & Imray, C. H. (2017). Frostbite. Emergency Medicine Clinics, 35(2), 281-299.”
This parapgraph is divided in two chapters, both derived from above source. The first part is the most important: prevention of frostbite. The second part is treatment of (non-severe) frostbite. For severe frostbite, a physician should always be contacted.
Prevention of frostbite
- Make sure that food & drinks are appropriate for the circumstances.
- Wear decent clothing, layered
- Keep them dry from sweat and avoid constricting items
- Wear good foot wear and take good care of your feet
- Taken altitude increases in consideration
- And wind-chill too
- Don’t rest too long
- Don’t touch metal objects when it is freezing
- When really cold: use mittens (rather than gloves) and don’t take them off unless absolutely necessary
Perform your evaluation of affected tissue in a good area: sheltered and preferably one from which you don’t need to move again any time soon. As soon as you take boots off, tissue might swell and this makes you unable to put them back on. Placing you between a rock and a hard place when done at an inappropriate location.
Treatment of frostbite
Again: only in non-severe cases. Be aware that frostbite might be accompanied with hypothermia. After all: it’s cold, otherwise the tissue wouldn’t be frozen. It’s also likely that more than 1 person of the group is affected.
- Do not rub against the affected tissue. It does heat up the tissue. It also destroys the tissue.
- Do not apply direct heat such as heat pads directly at the tissue.
- Put hands in your armpits or groin. This works with frostnip – not when worse.
- Do not walk on frostbitten feet – unless it is required to go to a safe(r) shelter first.
- Avoid re-freezing of the exposed limbs. So the “warming-up” should be definitely, and not temporarily.
- The limbs can be warmed with warm water. Check the temperature: affected tissue does not have temperature sensation.
- Once warmed, dry in the air. Do not rub.
- Leave blisters intact. They indicate thawing of the tissue. Hang the limb higher, as this avoids swelling.
That’s about as much as you can do. You can consider taking ibuprofen (again, paraphrasing the medical book here!), as this supposedly has an antiinflammatory function.
Don’t hesitate to contact a local physician to check your symptoms and whether extra treatment needs to take place by professionals.