Medicine: Environmental Injuries: 2. Frostbite and Trenchfoot

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2. Frostbite and Trenchfoot

I promised AfterEver information on cold injuries. Here is the much-delayed frostbite section.

This article is meant to give some pointers to authors. It is not intended to be comprehensive, and it simplifies many complicated issues. If you find something inaccurate, please email me. If you have questions that are not addressed, I'd be glad to add information to address them.

In this section I will discuss freezing injury, the most severe of which is frostbite, and non-freezing cold injury which is also called trenchfoot. Most of this material comes from Virtual Naval Hospital. I have paraphrased and simplified a great deal.


Frostbite results from the formation of tiny ice crystals in the fluid between the cells of the skin and nearby tissues, and is caused by exposure to temperatures below freezing. As might be expected, the severity and extent of injury increases with colder temperatures and longer exposure. Windchill also increases the likelihood of frostbite, as does damp clothing over the involved body part.

Frostbite most commonly occurs on the face, hands, and feet. Its onset is signaled by a sudden blanching (whitening) of the skin of the nose, ear, or cheek. This may be noticed by the character as a momentary tingling or "ping." Often, the patient feels that his face muscles will not work.

The first sign of frostbite is reddening of the skin This progresses until the affected part appears waxy and white, yellow-white, or mottled blue-white, and is hard, cold, and insensitive to touch. Inability to move the skin over the joints in a normal fashion is common. Even a very shallow or surface frostbite injury may have the appearance of being frozen completely solid simply because of the skin freezing. The degree of injury will not be immediately apparent.

The character will feel discomfort in the affected area, usually arms or legs, but ears or nose are also possible sites. Th discomfort is followed by varying periods of pain along with a cyclic, dull ache, which eventually subsides into a period of numbness. From there, the injury progresses even though it is painless. Patients often describe a sensation of walking on a wooden limb; because it is painless, they are often not aware of the presence or extent of injury.

Degrees of Injury (Not everyone will want to know this)

Experts in both frostbite and burns usually speak in terms of superficial and deep injury. Most people, even those in medicine who don't deal with environmental injuries as a matter of course, are used to classifying injury by degrees. Since more readers and authors are used to that system, I will explain the older degree system. Because frostbite is a continuum, it can take days or weeks for the difference between first, second, third, and fourth degrees to become completely clear.

First-degree Redness and swelling, along with transient tingling or burning, are early symptoms. The skin becomes mottled blue/grey and red, hot, and dry. Swelling begins within two or three hours and persists for ten days or more, depending upon the seriousness of the injury. The skin surface begins to peel in 5-10 days and may continue for as long as a month, but no deep tissue is lost. Tingling, aching, and death of tissue at the pressure points of the foot are common results. The affected limb may have long term increased sensitivity to cold and increased sweating, especially with repeated first-degree injuries.

Second-degree Injury starts as does first-degree, but progresses to blister formation, numbness, and deep color change. Swelling may occur, but it disappears within days. Vesicles, which look like small water filled blisters, appear within 12-24 hours, generally on the back of the hand or top of the foot. Blisters are a good sign as long as they are filled with clear fluid; if the fluid is bloody, they are not a good sign. When these vesicles dry they can form a thick black crust, called an eschar, which eventually falls off cleanly with pink healing tissue beneath. Throbbing and aching pain occurs 3-10 days after the frostbite injury. Increased sweating is apparent at the second or third week. Early rupture of the blisters with subsequent infection often occurs in second-degree cold injury. Infection greatly increases the severity of the frostbite injury.

Third-degree injury This involves the full skin thickness and extends into the tissue beneath the skin. The blisters are smaller and may be bloody. Generalized swelling of the affected part may occur, but it usually decreases within 5-6 days. Pressure increases inside the limb, and it is not uncommon for the pressure in third- and fourth-degree injuries to get so high that the blood can't flow into the limb properly. If this happens the healer must make a vertical incision to release the pressure.

The skin forms a thicker more intense black, hard, crust than that of the second-degree injury. When all the tissue that is going to die has done so (called demarcation) it sloughs, sometimes leaving skin ulcers underneath. If there is a complicating infection, tissue loss will be greater, or the infection can spread to healthy parts. The average healing time is about 2 months. Patients often complain of burning, aching, throbbing, or shooting pains beginning on the fifth day and usually lasting through four or five weeks. Increased sweating appears later and extreme cold sensitivity is a common result.

Fourth-degree injury If the extent of the tissue damage is so severe that the tissue will not be able to heal, no blisters will form, and the skin remains blue and cold. This is most commonly seen in the tips of fingers and toes, and the area will start to become black and dry up, (called 'mummification' as it is dry and brittle like a mummy) often within a few days. The mummification becomes more pronounced over a period of days, weeks, or months, and the demarcation between healthy and dead tissue becomes more obvious. The parts that are dead will gradually separate from the live parts until the dead tissue falls off by itself. Rapid freezing or freeze-thaw-refreeze makes this degree of injury more likely. Severe pain on rewarming, along with a deep bluish appearance, regularly occurs. With a slower freeze, there is some early swelling and deep pain, and demarcation takes much longer to occur. At 20-36 days it usually is obvious which parts of the limb will survive, but for bone it can take 60 or more days days.


The rules of treatment:
1. The gentlest possible handling of frozen parts to prevent additional injury, even so slight as that from rubbing against bedclothes.
2. Rapid thawing of the frostbitten part(s).
3. Prevention of infection.
4. Early gentle motion exercises of the injured part.
5. No surgery to remove frostbitten areas, even if it looks dead.

1. Whenever possible the character with frostbite of the feet should not have to walk, but should be carried or taken on a stretcher. On a horse the feet will hang down which is not desirable, but it is an improvement over walking.

All constricting items of clothing, such as boots, gloves, and socks, should be removed, but only when there is another way to keep the area warm. Therefore, the healer should not remove these if the character is still on top of Caradhras without shelter and fire, for instance. Boots and clothing frozen on the body should be thawed by immersion in warm water before removal. Treat the affected part very gently, don't rub, or apply lotions or creams; no massage, or moving the part to 'loosen it up'. The old remedy you see in books from the early 1900's of 'rubbing the part with snow' is an incredibly bad idea.

For frostbitten legs, keep the character at bed rest, with the part elevated and on clean sheets. Have someone rig a cradle or frame for the covers so that they do not directly touch the affected part. The healer should place small clean pieces of cloth between the toes to prevent them from rubbing each other.

If the hands are affected, rings should be removed from the fingers as soon as possible, or the progressive swelling will turn the ring into a tourniquet, cutting off circulation. When the arm is affected, elevate it on sterile towels, with special care to avoid injury to blisters.

Bearing weight on injured feet should not be allowed until healthy skin has developed over the affected areas.

2. The injured parts should be rewarmed rapidly by immersing in water at 100° to 108°F (37.5° to 42°C) with agitation of the bath water to hasten the warming. Although the thawing process is relatively quick, it is usually quite painful, and in real life potent painkillers would be used if available. Do not thaw at too high a temperature, or you will cause further injury to the damaged area. Keep the entire body warm.

As thawing proceeds, the skin surface will flush pink towards the fingers or toes. The part should stay immersed in the whirlpool bath until the most distant tip of the thawed part flushes, is warm to the touch, and remains flushed when removed from the bath.

Sensation often returns to the affected part with rapid thawing, but this is temporary. The sensation disappears once the blisters develop and separate the layers of the skin. Sensation does not fully return again until healing is complete.

Occasionally, the flush may not be pink, but rather burgundy or purple, colors which usually indicate poor blood flow but may simply be related to the temperature of the water. The color change is usually temporary, but persistent blue or purple color, despite rapid thawing, may indicate increasing pressure within limb and an incision to decrease pressure may be necessary.

3. The modern standard for prevention of infection is whirlpool baths at 98.6°F (37°C). The closest M-e equivalent would be pouring the water over the part in a pot or large container, periodically emptying the pot and starting over with clean water. This helps wash away dead tissue.

4. As soon as possible the patient should begin trying to move the fingers or toes gently, ideally every hour. These exercises are as simple as spreading and closing the toes or fingers. Most patients find the movement easier and less painful while the part is in warm water. The exercises are very important in the first six weeks to prevent joints and tendons from 'freezing' in position.

5. With frostbite, it takes quite a bit of time to see what will survive and what won't (demarcation); parts that look like they will die may recover given time. Correct care means waiting to see what will survive, with no surgery. As disturbing as it sounds, the healer should wait for the dead bits to drop off by themselves, which can be anywhere from 3 weeks to 4 months.

There are signs in early rewarming that let the healer know how the patient is likely to do:
(a) Good Signs:
Large, clear blisters developing early and extending to the tips of the fingers or toes; rapid return of sensation; return to normal temperature in the injured area; pink or mildly red skin color that turns white briefly with mild pressure.

(b) Poor Signs:
Hard, white, cold, and insensitive tissue; cold and blue tissue without blisters; complete absence of swelling; dark bloody blisters, early mummification; fever, rapid heartbeat, and weakness; other traumatic injuries; blue or dark red skin that does not blanch on pressure.

Only deeply infected areas should be debrided.

The longer the part is frozen, the more long term damage to the part. But the part should not be rewarmed if there is danger of refreezing; the danger of thawing and subsequent refreezing is greater than the danger of remaining frozen.

The new skin is very susceptible to minor trauma, as in walking, and is especially sensitive to cold. Therefore, the character must continue to protect the area.

Sleep and rest should be encouraged, as well as good nutrition and lots of liquids.

Smoking decreases the blood flow, and therefore is A Bad Thing. No pipeweed!

Strong pain medication may be needed in the first few days, after that it is not commonly needed.

Prevention for cold injury:
A pneumonic is the word C-O-L-D:
Cleanliness and Care - Feet, socks, and clothing are warmer when clean. Proper care of the feet is imperative.
Overheating - Wearing too much clothing causes overheating, perspiration, dampness and then coldness.
Layers and Looseness - Clothing in loose layers assures air spaces which hold body heat. Adjust the number of layers to the temperature and activity. Loose-fitting clothing insures circulation and insulation.
Dampness - A wet garment is a cold garment.

"Trench Foot" (or "Immersion Foot")

Trenchfoot is caused by prolonged exposure to wet, cold foot gear or outright immersion of the feet at low temperatures, usually 32 - 50° F or 0 - 10° C. The common symptoms are redness, swelling, blistering, bleeding, and numbness. When the limb becomes numb, the victims are not aware of how severe the problem is, and tend to ignore it.

At the upper range of temperatures, exposures of 12 hours or more will cause injury. Shorter durations of exposure at or near 32°F or 0°C will cause the same injury. Having the feet down instead of elevated, and limiting movement of the feet aggravates and increases the likelihood of the condition. Sailors in sea water or soldiers and marines with wet feet in trenches, or foxholes develop trench foot.

The same type of problem can occur with warm water, but will take longer. In these cases, the injury consists of whitening and wrinkling of the skin and pain in the feet after two days or more of water exposure. Additional exposure results in reddening and swelling of the weight-bearing surfaces (soles of feet). Complete recovery occurs following proper foot care. This can be prevented if the characters are able to dry their feet for six to eight hours per day with boots and socks off.

This is a work of fan fiction, written because the author has an abiding love for the works of J R R Tolkien. The characters, settings, places, and languages used in this work are the property of the Tolkien Estate, Tolkien Enterprises, and possibly New Line Cinema, except for certain original characters who belong to the author of the said work. The author will not receive any money or other remuneration for presenting the work on this archive site. The work is the intellectual property of the author, is available solely for the enjoyment of Henneth Annûn Story Archive readers, and may not be copied or redistributed by any means without the explicit written consent of the author.

Story Information

Author: Lyllyn

Status: General

Completion: Ongoing Serial

Era: Multi-Age

Genre: Research Article

Rating: General

Last Updated: 05/02/03

Original Post: 12/28/02

Go to Medicine: Environmental Injuries overview


WARNING! Comments may contain spoilers for a chapter or story. Read with caution.

Medicine: Environmental Injuries

Kateydidnt - 01 Feb 06 - 12:29 AM

Ch. 2: Frostbite and Trenchfoot

I always thought that for frostbite, you had to go from cold to lukewarm and then warm water rather than warm water only.  Is this an old wives tale? Would it have been a method use in ME?

Medicine: Environmental Injuries

Lyllyn - 02 Feb 06 - 4:00 PM

Ch. 2: Frostbite and Trenchfoot

Modern medicine has found that rapid rewarming is the way to go. A reference, if you're interested, is here,  under "treatment."

 It's an interesting question whether they would have done it that way in ME - I'd guess you could successfully write it either way. There were people in the past who advocated rubbing the frostbitten part with snow (a terrible idea!).

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