Frostbite

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at March 15, 2016
StartDiseasesFrostbite

Anyone exposed to harsh, cold conditions is at risk of developing frostbite. Understanding the dangers and dressing appropriately are crucial to preventing injury.

Contents

Definition & Facts

Frostbite occurs when skin and underlying tissues gradually freeze and remain frozen for a period of time. Ice crystal formation causes tiny blood vessels to narrow, choking the oxygen supply to skin cells. Toes, fingers, earlobes, cheeks, the tip of the nose, and the chin are most vulnerable to overexposure.

In extreme conditions, freezing can begin in seconds, and frostbite can take hold in as few as ten minutes. Untreated frostbite can cause skin, bone and muscle damage. In severe cases, nerve damage and infection are possible. Long-term complications may include ongoing numbness, cartilage damage, gangrene and growth defects in children. There is also a higher likelihood of developing frostbite again.

Symptoms & Complaints

Frostbite takes place in stages. It shouldn’t be confused with the milder condition frostnip, which can be treated by rewarming the skin and applying first aid. There might be uncomfortable tingling as the skin warms up, but frostnip doesn’t cause permanent damage. However, it is the first stage of frostbite and should be taken as a serious warning sign.

The second stage is called superficial frostbite. An important difference between frostbite and simple cold damage is the texture and color of the skin. Normally, skin reddens and starts to hurt at low temperatures. If the skin starts to pale, become waxy or turn unusual colors, frostbite may be setting in.

As ice crystals form in underlying tissue, there might be prickling and a false sensation of warming. That is why it’s so common for people to remain oblivious to frostbite until someone points it out to them. Rewarming the skin during this stage may cause painful swelling and burning. Skin surface will have a mottled appearance, and blisters may erupt over the next day or two.

Deep, severe frostbite is the final stage, and all skin layers are affected. Most victims experience numbness rather than discomfort. Joints and muscles stiffen and stop working. Large blisters form one to two days after the skin is warmed. The tissue starts to die, and affected areas turn hard and black. Anyone displaying symptoms should seek medical attention right away. If exposure was extreme enough to cause frostbite, hypothermia—with its own host of problems—is also a realistic concern.

Causes

Aside from extreme cold, high altitude and wind speed impact the rate at which skin freezes. Many victims of frostbite had failed to consider the wind chill factor. In some densely populated U.S. cities where one may not expect it, wind chill can cause temperatures to dip as low as minus 35 degrees Fahrenheit (minus 37 degrees Celsius). Precipitation and heavy sweating, which leave skin and clothing damp, put campers, hikers and athletes at risk. When it’s impossible to change into dry things, skin is prone to freezing.

Infants and seniors have a harder time producing body heat and staying warm, and frostbite is also a chronic problem among the homeless. It may even occur after prolonged contact with ice, frozen metal or a cold compress. Other conditions that increase risk include the following:

Diagnosis & Tests

Factors considered in diagnosis include environmental conditions, length of exposure, and skin condition. The doctor will perform a physical examination and investigate symptoms. After examination, a doctor may order conventional X-rays or angiography, which uses dye injection to examine blood vessels. Thermography measures blood flow using a heat-sensing device.

These and other tools are useful for predicting the progression of frostbite and, if it’s severe enough, identifying tissue that will have to be surgically removed. More can be learned once the blood vessels stabilize three or four days after rewarming. An CT scan, MRI or a bone scan might be called for in rare, complex cases.

Treatment & Therapy

While the patient waits to see a doctor, he or she should change into dry clothes and protect the frostbitten areas from further exposure to cold. If his feet are affected, he shouldn’t walk or put weight on them. He should take care with blisters and not lance or otherwise disturb them. Direct heat from a fireplace, car heater, stove or heating pad should be avoided—there is risk of thawing and refreezing, which makes frostbite even more dangerous.

In treatment facilities, affected areas are rewarmed gradually and gently. Hands and feet are soaked in warm water for 20-30 minutes at a temperature between 104 degrees Fahrenheit and 108 degrees Fahrenheit (40-42 degrees Celsius). Aloe vera is applied to the injury before wrapping and elevating. If the injury reached the bone, splints or braces are used to stabilize it.

Blisters are usually cleaned and dressed to prevent infection. Most patients experience a great deal of pain as feeling returns during rewarming, and prescription painkillers are sometimes necessary. Since tetanus is a threat, patients who have never been vaccinated or not vaccinated in the last 10 years may be given a shot first thing. Penicillin might be used to combat infection, and ibuprofen keeps inflammation in check. Further hospital treatment might include the following:

Prevention & Prophylaxis

Wind-resistant and water-resistant clothing and insulating footwear are crucial to preventing frostbite. Since tight clothes inhibit blood circulation, garments should have plenty of breathing room and be worn in layers. Hands, feet and the head should be covered, and wet items should be exchanged for dry ones as soon as possible.

Children and teenagers shouldn’t play near bodies of water in very cold weather. Keeping track of time spent outdoors is vital; drugs, alcohol and anything else that impairs judgment are to be avoided. Above all, winter warnings should be heeded and plans changed if necessary.