How is frostbite caused

Philadelphia, PA: Elsevier; chap Zafren K, Danzl DF. Accidental hypothermia. Frostbite and nonfreezing cold injuries. URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit.

Learn more about A. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions.

Call for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright A. Any duplication or distribution of the information contained herein is strictly prohibited. Access myPennMedicine For Patients and Visitors.

Patient Information. Conditions Treated A-Z. Definition Frostbite is damage to the skin and underlying tissues caused by extreme cold. Alternative Names Cold exposure - arms or legs Causes Frostbite occurs when the skin and body tissues are exposed to cold temperature for a long period of time.

In areas of the body affected by frostbite, ice crystals form and cells and blood vessels become damaged. Blood clots can also form in small blood vessels which further reduces the chance of blood and oxygen getting to the affected tissues.

The chance of frostbite is increased the longer that you are exposed to the cold temperatures. If the cold temperatures are accompanied by wind producing wind chill which brings the temperature down further or high altitude there is a greater risk. Generally, frostbite is worst in lower temperatures.

However, it can affect anyone who is exposed to low temperatures below freezing - in particular, those who wear inadequate clothing. If you have underlying health problems such as narrowing of the arteries, mainly occurring in the legs peripheral arterial disease or diabetes, you have an increased risk of developing frostbite. If you take certain medicines that narrow constrict your blood vessels, your risk is increased.

Beta-blockers are a good example of this. You are more at risk of developing frostbite if you smoke, as the chemicals in cigarettes can cause your blood vessels to constrict. You are more at risk of developing frostbite if you have had alcohol or recreational drugs which make you drowsy or behave differently to usual.

This is because you may be less aware of how cold you are and less aware that you are in danger. You are then less likely to get out of the cold, or protect yourself from it. People who have Raynaud's phenomenon a condition where the small blood vessels of the fingers constrict also have an increased risk of developing frostbite.

Give yourself a check-up with a general blood profile, now available in Patient Access. Frostbite injuries are classified by the degree of injury. The degree of frostbite basically refers to how deep the frostbite goes. Your skin has two layers - the outer layer epidermis and the dermis.

The dermis sits just under the epidermis. Beneath the dermis is a layer of fat, and then the deeper structures such as muscles and tendons. Frostbite can be described using these four levels but it may simply be described as superficial frostbite or deep frostbite. Superficial frostbite corresponds to first-degree or second-degree frostbite. Deep frostbite corresponds to third-degree or fourth-degree frostbite.

These are important because superficial frostbite means there is likely to be very little or no tissue loss. Deep frostbite suggests there will be greater tissue loss. Frostbite can cause feelings of cold and firmness in the affected area, such as the fingers or toes. Stinging, burning and numbness can also occur.

You may experience pain, throbbing, burning or an electric current-like sensation when the affected area is re-warmed. In first-degree frostbite, the affected area of skin usually becomes white and feels numb. Sometimes the skin is red. It may also feel hard or stiff. If it is treated quickly, the skin usually recovers fully.

In second-degree frostbite, the affected skin is often red, or may become blue. It feels frozen and hard. The symptoms of frostbite usually begin with the affected parts feeling cold and painful. If exposure to the cold continues, you may feel pins and needles before the area becomes numb as the tissues freeze. A doctor will examine the affected area, check your vital signs, and ask how you got frostbite. You may need a follow-up appointment or referral to a specialist, as the full extent of a frostbite injury often isn't apparent until a few days later.

A person with frostbite should be taken to a warm environment as soon as possible. This is to limit the effects of the injury and because it's also likely they'll have hypothermia. Don't put pressure on the affected area. The frostbitten area should be warmed up by a healthcare professional.

This is usually done by immersing the affected area in warm — but not hot — water. A bath of water at 37C to 39C The rewarming process is often painful, and regular strong painkillers may be needed. It's important not to rewarm the affected area if there's a chance of it freezing again, as this can lead to further tissue damage.

If frostbite is severe, the loss of blood supply to the tissue may cause it to die gangrene. A type of surgery called debridement may be needed to remove the dead tissue. Amputation may be needed if frostbite is severe.

Frostbite and nonfreezing cold injuries. Philadelphia, Pa. McIntosh SE, et al. Wilderness Medical Society practice guidelines for the prevention and treatment of frostbite. Bergeron MF, et al. International Olympic Committee consensus statement on thermoregulatory and altitude challenges for high-level athletes.

British Journal of Sports Medicine. Miller T. Preparing for cold weather exercise. Performance Training Journal. Briggs JK. In: Triage Protocols for Aging Adults. Wolters Kluwer; Thompson DA.

American Academy of Pediatrics; Kelly AP, et al. Biology of wounds and wound care. McGraw-Hill Education;