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Symptoms and Signs of Frostbite Causes, Stages, Pictures, and Treatments

Doctor's Notes on Frostbite Causes, Stages, Pictures, and Treatments

Frostbite refers to severe damage to tissues that is caused by prolonged exposure to extremely cold temperatures. It results from the formation of ice crystals within cells, rupturing the cells and leading to cell death. There are three stages of frostbite, frostnip (first degree injury), second, third, and fourth, which is the most severe form of frostbite.

Signs and symptoms of frostbite include pain in the affected area, numbness, burning, tingling, pale skin, and the development of clear blisters. Other associated symptoms of deep frostbite can include complete loss of sensation in the affected area, skin changes such as a pale, yellowish, bluish, gray, or mottled skin color; blood-filled blisters on the skin, and a firm, solid feel to the affected area.

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Medically Reviewed on 3/25/2019

Frostbite Causes, Stages, Pictures, and Treatments Symptoms

Varieties of frostbite classification systems have been proposed. The easiest to understand, and perhaps the one that gives the best clues to the outcome, divides frostbite into two main categories: 1) superficial and 2) deep.

  • In superficial frostbite, you may experience burning, numbness, tingling, itching, or cold sensations in the affected areas. The regions appear white and frozen, but if you press on them, they retain some resistance.
  • In deep frostbite, there is an initial decrease in sensation that is eventually completely lost. Swelling and blood-filled blisters are noted over white or yellowish skin that looks waxy and turns a purplish blue as it rewards. The area is hard, has no resistance when pressed on, and may even appear blackened and dead.
  • The affected person will experience significant pain as the areas are rewarmed and blood flow reestablished. A dull continuous ache transforms into a throbbing sensation in 2 to 3 days. This may last weeks to months until final tissue separation is complete.
  • At first, the areas may appear deceptively healthy. Most people do not arrive at the doctor with frozen, dead tissue. Only time can reveal the final amount of tissue damage.

There are milder conditions related to frostbite, including frostnip, chilblains, and trench foot.

  • Frostnip refers to the development of tingling sensations (paresthesias) that occur due to cold exposure. They disappear upon rewarming without any tissue damage.
  • Chilblain (or pernio) refers to a localized area of tissue inflammation that appears as swollen and reddish or purple. These develop in response to repeated exposure to damp, cold conditions above the freezing point. Chilblains may itch or be painful.
  • Trench foot was described in World War I as a result of repeated exposure to dampness and cold and exacerbated by tight boots. The affected feet are reddened, swollen, painful or numb, and may be covered with bleeding blisters. This condition is still observed in some homeless persons today.

Symptoms follow a predictable pathway. Numbness initially is followed by a throbbing sensation that begins with rewarming and may last weeks to months. This is then typically replaced by a lingering feeling of tingling with occasional electric-shock sensations. Cold sensitivity, sensory loss, chronic pain, and a variety of other symptoms may last for years.

The treatment of frostbite is done over a period of weeks to months. Definitive therapy such as surgery may not be performed for up to 6 months after the initial injury. Therefore, it is important to establish a working relationship between you and your doctor that will continue throughout the healing process.

Frostbite Causes, Stages, Pictures, and Treatments Causes

Your body works to stay alive first and to stay functioning second.

  • In conditions of prolonged cold exposure, the body sends signals to the blood vessels in the arms and legs telling them to constrict (narrow). By slowing blood flow to the skin, the body is able to send more blood to the vital organs, supplying them with critical nutrients, while also preventing a further decrease in internal body temperature by exposing less blood to the outside cold.
  • As this process continues and the extremities (the parts farthest from the heart) become colder and colder, a condition called the hunter's response is initiated. The body's blood vessels are dilated (widened) for a period and then constricted again. Periods of dilatation are cycled with times of constriction in order to preserve as much function in the extremities as possible. However, when the brain senses that the person is in danger of hypothermia (when the body temperature drops significantly below 98.6 F [37 C]), it permanently constricts these blood vessels in order to prevent them from returning cold blood to the internal organs. When this happens, frostbite has begun.
  • Frostbite is caused by two different means: cell death at the time of exposure and further cell deterioration and death because of a lack of oxygen.
    • In the first, ice crystals form in the space outside of the cells. Water is lost from the cell's interior, and dehydration promotes the destruction of the cell.
    • In the second, the damaged lining of the blood vessels is the main culprit. As blood flow returns to the extremities upon rewarming, it finds that the blood vessels themselves are injured, also by the cold. The vessel walls become permeable and blood leaks out into the tissues. Blood flow is impeded and turbulent and small clots form in the smallest vessels of the extremities. Because of these blood flow problems, complicated interactions occur, leading to inflammation that causes further tissue damage. This injury is the primary determinant of the amount of tissue damage that occurs in the end.
    • It is rare for the inside of the cells themselves to be frozen. This phenomenon is only seen in very rapid freezing injuries, such as those produced by frozen metals.

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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.