The stages of frostbite consists of several phases. In the first phase of frostbite, the skin temperature begins to drop, and blood flow to the surface of the skin dramatically decreases. As the cooling process begins, the body initiates the Hunting response, a 5-10 minute cycle where the blood vessels dilate, and then contract, which is the body’s attempt to re-warm. Hunting response is more frequently seen in populations native to cold environments such as Eskimo’s, where the response is far stronger. The medical term used for the Hunting response is cold-induced vaso-dilation. The first phase is defined as a pre-freeze phase.
The second phase is considered a freeze-thaw phase. It is between the freeze-thaw phase and the vascular stasis or third phase that we see intracellular fluid shifting across cell membranes. Theoretically it is thought that this is the phase where actual ice crystal formation occurs.
The next phase, the late ischemic phase, is the most severe. During this phase, the skin becomes necrotic and gangrenous. There can actually be bone involvement during this phase.
It is important to note phases can, and often do, overlap.
Frostbite can be classified in different degrees or stages, much like burns. 1st degree frostbite shows partial skin redness (erythema), swelling, usually no blisters. Symptoms include burning or throbbing pain. Stinging is sometimes reported by some patients. 2nd degree is redness. Sometimes vesicles and blisters are seen. These blisters can form a blackened area on the skin. Numbness is a symptom often seen. 3rd degree burns are much deeper, where there is full-thickness freezing of the skin, with hemorrhagic blisters. There can be some skin death. Symptoms include feeling of no sensation, burning, throbbing and aching (please see frostbite picture on Survive Outdoors, emergency photo section, for 3rd degree frostbite).
4th degree frostbite is the most severe state. It is usually full-thickness, involving muscle, tendons and bones. There is minimal swelling. At this point, these look very mummified. Pain at the joints is a possible symptom. This system of classification has received widespread use, especially by emergency rooms.
Frostbite Treatment –Outdoor Treatment for Frostbite
Outdoor treatment is relatively simple. All wet clothing should be removed, replaced by dry clothing, if available. Wrapping the areas in sterile gauze, if available, would be highly beneficial. However if not available, wrapping in any dry material is advised. Elevate the frostbitten area. Rapid re-warming has proven to be the most important treatment modality. However, there is some controversy surrounding the re-warming process. Some individuals believe that re-warming should occur only after being transported out to an ED (emergency department). Others suggest that rapid re-warming should occur in the field, running the risk of possibly refreezing the affected body part. If an affected individual is 4-5 days from being transported out, this author believes waiting until arrival in the ED before re-warming is the safest and best option.
Other outdoor treatment should be placing cotton or cut up pieces of clothing between the toes or fingers. DO NOT DEBRIDE BLISTERS, as you will increase risk of infection.
When considering re-warming in the outdoors, many individuals think of warming water over a fire and using a thermometer to gauge the temperature. Of course this is rather ridiculous, as most individuals do not carry a thermometer with them in the outdoors. Subsequently, a nice rule of thumb is as follows: Water should be warmed to approximately 104 degrees Fahrenheit. This is the water that should be used to rapidly re-warm. This temperature is about that of a hot tub. After warming the water, if you place your hand in the water and immediately have to take it out, it is clearly above 104 degrees. At 104 degrees, one can leave their hand in the water for an extended period of time without feeling pain.
AT THE RISK OF BEING REDUNDANT, ONLY CONCERNED, REMEMBER: DO NOT RUB SNOW ON ANY FROSTBITTEN AREA.
You can treat with nonsteroidal anti-inflammatories such as Ibuprofen, which also helps with anti-prostaglandin formation.