Exposure to cold temperature without adequate protection can result in frostbite. Frostbite means that a part of a body has been frozen and this can be quite dangerous. Usually it is the face, nose, ears, fingers and toes that get frostbitten. Frostbite can occur during any outdoor activity including play, and especially fast moving sports such as skating, skiing, snowboarding and tobogganing. Obviously the colder and windier it is, the quicker an unprotected body part or area will become frostbitten.
The skin around a frost bitten area initially becomes red then pale and very rarely bluish. As the skin warms up there can be some blisters.
Cold exposure leads to ice crystal formation, cellular dehydration, protein denaturation, inhibition of DNA synthesis, abnormal cell wall permeability, damage to capillaries, and pH changes. Rewarming causes cell swelling, erythrocyte and platelet aggregation, endothelial cell damage, thrombosis, tissue edema, increased compartment space pressure, bleb formation, localized ischemia, and tissue death.
The physiology 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.
Proper clothing for winter weather insulates from the cold, lets perspiration evaporate and provides protection against wind, rain and snow. Wear several layers of light, loose clothing that will trap air, yet provide adequate ventilation. This is better protection than one bulky or heavy covering. Best fabrics for the cold are wool, polyester substitutes and water-repellent materials (not waterproof, which holds in perspiration). Down coats and vests are warm; however, if down gets wet it is not an effectively warm fabric. Coverings for the head and neck are important. Hats, hoods, scarves, earmuffs and facemasks are good protection.
Protect your feet and toes. Wear two pairs of socks - wool is best, or cotton socks with a pair of wool on top. Wear well-fitted boots that are high enough to cover the ankles. Hand coverings are vital. Mittens are warmer than gloves, but may limit what you can do with your fingers. Wear lightweight gloves under mittens so you'll still have protection if you need to take off your mittens to use your fingers. Be sure your clothing and boots are not tight. A decrease in blood flow makes it harder to keep the body parts warm and increases the risk of frostbite. When in frostbite-causing conditions, dress appropriately, stay near adequate shelter, avoid alcohol and tobacco, and avoid remaining in the same position for long periods.
Keep the affected part elevated in order to reduce swelling. Move to a warm area to prevent further heat loss. Note that many people with frostbite may be experiencing hypothermia. Saving their lives is more important than preserving a finger or foot. Remove all constrictive jewelry and clothes because they may further block blood flow. Give the person warm, nonalcoholic, noncaffeinated fluids to drink. Apply a dry, sterile bandage, place cotton between any involved fingers or toes (to prevent rubbing), and take the person to a medical facility as soon as possible. Never rewarm an affected area if there is any chance it may freeze again. This thaw-refreeze cycle is very harmful and leads to disastrous results. Also, avoid a gradual thaw either in the field or in the transport vehicle. The most effective method is to rewarm the area quickly. Therefore, keep the injured part away from sources of heat until you arrive at a treatment facility where proper rewarming can take place. Do not rub the frozen area with snow (or anything else, for that matter). The friction created by this technique will only cause further tissue damage. Above all, keep in mind that the final amount of tissue destruction is proportional to the time it remains frozen, not to the absolute temperature to which it was exposed. Therefore, rapid transport to a hospital is very important.
After initial life threats are excluded, rewarming is the highest priority. This is accomplished rapidly in a water bath heated to 40-42°C (104-107.6°F) and continued until the thaw is complete (usually 15-30 minutes). Narcotic pain medications may be given because this process is very painful. Because dehydration is very common, IV fluids may also be given. After rewarming, post-thaw care is undertaken in order to prevent infection and a continuing lack of oxygen to the area. The clear blisters are removed while the bloody ones are left intact so as not to disturb the underlying blood vessels. A tetanus booster is given if needed. People with frostbite are hospitalized for at least 1-2 days to determine the extent of injury and to receive further treatment. Aloe vera cream is applied every 6 hours, and the area is elevated and splinted. Ibuprofen is given twice per day to combat inflammation and penicillin or another appropriate antibiotic given to prevent infection. For deep frostbite, daily water therapy in a 40°C (104°F) whirlpool bath will be performed in order to remove any dead tissue. A number of experimental therapies do exist, many of which aim to further treat the inflammation or decreased blood flow seen in frostbite. As of yet, none of these treatments has proven beneficial.