Cold Injuries

Cold injuries, such as frostbite and chilblains are common during the winter months when people are out exposing themselves to the elements. Many people think that for a cold injury to occur the temperature has to be below freezing (0 degrees C, 32 degrees F) but in fact cold injuries can occur in temperatures above freezing if there’s a wind chill or a glove or sock gets wet. There are two types of cold injuries, the ones where body tissues freeze and the ones where they do not. The people most susceptible to cold injuries are the young and the elderly, although anyone who exposes him or herself to the cold is at risk.

Cold Injury Classification:

No tissue freezing

Chilblains: these are the most common cold injuries. They tend to occur when there is exposure of skin to a dry cold. In this case, the affected area may itch and appear reddish blue and be swollen and painful. Over time blisters containing clear fluid may form and the area will be sensitive to cold in the future. Luckily there is often no permanent damage.

“Trench Foot”: The name of this condition comes from the cold injury that often took hold on the soldiers living in the trenches during World War I. This condition also goes by the title of Immersion injury. These injuries occur when a part is the body is exposed to a cold and wet environment. For example, if while playing out in the snow your socks get wet you are increasing your risk of developing trench foot is you fail to correct this problem. These are like chilblains, except they are often more serious. The blisters are deeper and resemble those of burns, and the area remains sensitive to the cold. Again there is usually no permanent damage.

Tissue freezing

Frostbite: this is probably the most serious cold injury. In this injury the tissues of the affected area actually freeze. Ice crystals form within the cells, causing the cells to rupture and die. Luckily this injury has several stage and can be caught early.

The first stage is called “frostnip” this occurs when only the surface skin is frozen. It starts like a chilblain, with itching and pain. The skin then progresses to loose it’s blood supply, and eventually looses feeling and goes numb. Because only the top layers of skin are affected, there is usually no permanent damage aside from long-term sensitivity to cold, which may occur.

The second stage occurs if no action is taken in the situation described above. In this case the skin becomes hard and frozen , luckily deep tissues are spares and remain soft. Several days (usually 1-2) after the injury occurs, hard blisters will form. They often appear blackened and look worse than they are and heal within about 3-4 weeks. These injuries should usually be seen by a doctor and again the only permanent damage is heat and cold sensitivity.

If the injury progresses to the third (or fourth, depending on severity) stage of frostbite then the deep tissues are affected. Here the muscles, tendons, blood vessels and nerves of the affected area are frozen. The area will feel hard and woody and you may not be able to move the part on it’s own (for example, if your fingers are affected you will lose the use of them). This loss of use may be temporary or in serious cases permanent. The affected area looks either deep purple or red with blisters, which are usually filled with blood. Frostbite such as this usually results in the loss of fingers and toes. Often it may take several months to determine the extent of the damage, and surgery is usually delayed until they are certain that the tissues cannot be revived.

How do I treat these injuries?

There are a few important things to remember when treating these injuries the first of which is vital. It is very important never to thaw an affected area if there is a risk that it may re freeze. If it is warmed then refrozen ice crystals will form and more damage will be done. If you are afraid the area will become re frozen then leave the affected area frozen. Another mistake would be to follow the old folk remedy of rubbing the affected area with dry snow. Any rubbing may aggravate the area and cause more damage. Warming the injury is the proper treatment but cold injuries should never be warmed over a fire or next to a heater. This could cause painful burns and dry out the injured tissues, causing again, more damage.

The proper way to treat these injuries is to put the affected area into a tub of hot water (104-108 degrees F and 40-42 degrees C). It is very important to take the temperature of the water with a thermometer or a hand that is not frozen. It is very important to avoid burning the injured area, and it may not always be obvious because these areas often lack feeling. When feeling is returned there may be quite a bit of pain in some cases. Aspirins, ibuprofen, and acetaminophen may be used for the pain. If you feel stronger pain control is needed contact your doctor.

Who is most at risk?

As mentioned above the young and elderly are at the greatest risk. The elderly have poor circulation and children have smaller limbs which freeze much faster. In both cases they may not be able to get help or recognize the problem before the injury is upon them. Other people at risk are those who consume alcohol during the cold winter months and those who are taking medications that depress the ability to feel naturally. These people may not recognize they are in trouble until it is too late. Alcohol causes warm blood to become cooled at the surface of the skin, which sets the person at a greater risk of getting a cold injury. And lastly those who have illnesses such as diabetes, poor circulation, hypothyroidism and arteriosclerosis are at a greater risk as well.

How do I prevent a cold injury?

The best way to prevent these injuries is simple. Dress warmly and move indoors when your fingers, toes, or face begin to feel cold. Always keep your hands and feet dry and covered, and change wet gloves and socks as soon as possible. It’s also good to keep your ears covered. Several drugs have also been tried to prevent frostbite by dilating the blood vessels and increasing circulation but the effectiveness of these is anecdotal, and it has not been proven to help. Medications to avoid are beta-blockers. These medications reduce circulation and increase the risk of cold injuries.

When is medical help advised?

Chilblains can usually be treated at home, while a doctor should look at trench foot and frostbite cases. Those two injuries require long-term evaluations to watch for complications. Infection of a cold injury is often increasing redness and warmth. Also, if there is a lot of blistering and you are not up to date on your tetanus shot, you should get a booster. If you are unable to get medical care for your chilblain cold injury, try to keep the blisters closed, and clean. If they do open let them drain then cut off any dead tissues with a pair of sterile scissors. Once the blister is open, it is important to keep it clean and covered. A first aid cream such as bacitracin may be used.