With the winter months upon us, cold injuries are becoming more commonly seen in the community. This is particularly true in cold climates, but it doesn’t take freezing temperatures to cause cold injury. With the addition of a moist environment and prolonged exposure to the elements, cold injuries can be seen in moderate temperatures. Here are five different types of cold injuries, and some of the key aspects of each:
- Trench Foot – Trench foot was named after the injuries mostly seen during World War II. It occurs at temperatures above freezing, and has been reported to occur in temperatures up to 60 degrees Fahrenheit. When the feet are exposed to a cold, damp environment for an extended period of time, that is when Trench Foot may appear. The addition of a constrictive shoe causes blood to leave the feet, further adding to the problem. The affected foot, ankle, and leg will be swollen and cold, with blotchy skin. It is typically painful or numb, and will usually be red. There may or may not be bleeding blisters on the feet as well.
- Immersion Foot – This is a condition that occurs after exposure to a wet, warm environment, typically for a period of longer than 48 hours. The skin will appear blanched, and there may be macerations on the feet as well. This condition appears very similar to Trench Foot, but is usually associated with a longer period of time.
- Frostnip – Frostnip is a superficial cooling of the tissues without cellular destruction, even though there is formation of ice crystals within these tissues. The term frostnip is often used synonymously with a first degree frostbite. It most commonly effects areas exposed to freezing temperatures or areas of poor circulation, such as the cheeks, earlobes, nose, fingers, and toes. There is typically pain, numbness, or tingling to the effected area, and a paleness to the skin. Frostnip will usually resolve with re-warming, and will not typically leave any permanent tissue damage.
- Frostbite – Frostbite is perhaps the most commonly seen of the cold injuries, particularly in cold climates. It occurs when the body is exposed to freezing temperatures and can occur in minutes to body parts that are already cold, such as the fingers and toes, as well as the nose and earlobes. Additional contributory factors include wind chill, wet clothing, alcohol or tobacco use, poor circulation, diabetes, neuropathy, or in patients taking beta-blockers. Frostbite is often classified based on the extent of damage, ranging from superficial damage like frostnip, to serious, life-threatening damage including gangrene and loss of the part.
- Pernio (Chillblains) – Pernio, sometimes called Chillblains or erythrocycosis, refers to inflamed tissue of a of a purple or red hue that develops in response to repeated exposure to cold, damp conditions above freezing. It is most commonly seen in children, and typically appears as circular markings on the tips of the toes or fingers. It may be associated with a burning, tingling, or itchiness as well.
The most important piece of the treatment for any of these conditions is the recognition of risk factors and prevention. The elderly are at a particularly high risk, due to susceptible tissues and poor circulation. Also at risk are the homeless, and anyone who spends a lot of time outdoors for extended periods of time, such as outdoor enthusiasts and hunters. Diabetics are also at high-risk, often due to poor circulation as well as neuropathy.
Preventative measures include wearing proper shoes in inclement weather. Waterproof shoes and boots should be worn in any type of damp environment, particular if the exposure time will be for longer than an hour. Socks should be changed when they become damp, and wool or acrylic socks should be worn by those that plan on being outside for extended periods of time.
Re-warming the effected areas may be done by either passive or active re-warming. Passive re-warming involves using one’s own body heat to re-warm. This may include keeping the area, such as the hands, tucked underneath the armpits or within a blanket. Active re-warming uses outside heat to re-warm, such as warm liquids and drinks. A good drink should be warm, non-alcoholic, and without caffeine. The presence of alcohol or caffeine may actually decrease body temperature, further exacerbating the problem.
A patient should be re-warmed as quickly as possible, without burning the patient. Typically a patient should be re-warmed at a rate no faster than 1 degree Celsius per hour, to avoid pain and other complications. Re-warming areas with tissue damage can be painful, and pain medications are often given to combat this.
For most conditions, passive re-warming is adequate. It is important for someone with a cold injury not to try to warm themselves up by rubbing the area. The skin overlying the affected area is often quite macerated, and rubbing the area can cause a breakdown of the skin. When the body’s natural barrier is broken down, it can lead to infections and possible gangrene.
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