Frostbite and Other Cold-Weather Foot Conditions

Understanding the Causes, Symptoms, and Treatments

Frostbite on the toes
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With prolonged exposure to cold weather, your feet are often the first part of the body to feel the uncomfortable effects. In an effort to keep our core body temperature stable, blood vessels within our arms and legs will constrict (narrow), which is why they are the first parts of our bodies to get cold when temperatures drop.

Cold weather injuries such as frostbite are a common concern for people who work outdoors during the winter or engage in outdoor winter activities. These injuries can range from mild to severe, with some of the more serious cases requiring amputation and rehabilitation.

Frostnip

Frostnip is a mild form of frostbite which occurs after a brief exposure to freezing temperatures. Unlike true frostbite, no actual freezing of the skin tissues occurs, so frostnip usually causes no lasting damage once the feet have been rewarmed. Symptoms of frostnip include a prickly pain and skin color changes, such as whitening (blanching) or redness.

Frostnip can be treated by warming the skin. You can do so by bundling up in a warm towel pulled from a dryer or with by soaking in warm—but not hot—water.

Frostbite

Frostbite can occur with exposure to freezing temperatures at or below 32o F (0o C). Frostbite is characterized by the actual freezing within the skin layers, leading to varying degrees of skin damage.

In the early stages of frostbite (known as first-degree frostbite), symptoms are similar to frostnip, including pale skin that becomes red and swollen upon warming. Numbness may also occur, which can increase the risk of injury if you don't feel pain or damage being done.

If freezing temperatures continue, the damage can extend to the dermal layer of skin and cause blistering (second-degree frostbite). With third-degree frostbite, the damage will progress to subcutaneous tissues, causing blisters to worsen and fill with blood.

Fourth-degree frostbite is the most serious stage, characterized by the development of gangrene and the inevitable amputation of one or more toes or fingers. Even the ears and nose can be severely affected by frostbite.

Depending on the damage incurred, treatment may involve:

  • Rewarming the skin with a warm-water bath
  • Wrapping the skin loosely with sterile sheets or dressings
  • Oral pain medications
  • Antibiotics to prevent infection
  • Anti-clotting drugs to improve blood flow in the feet, hands, ears, and nose
  • Removal of damaged tissue (debridement) one to three month after the injury
  • Whirlpool therapy and/or physical therapy during rehabilitation

It is important to recognize the early sign of frostbite to avoid permanent injury. Seek warmth and shelter the moment numbed areas of your feet, feet, or ears begin to turn white or purplish and start feeling warm rather than cold.

Immersion Foot

Immersion foot, also known as trench foot, can occur as a result of prolonged exposure to cool, damp conditions. Though the symptoms of immersion foot are similar to frostbite, the condition is characterized by exposure to non-freezing temperatures.

Immersion foot can develop in people who work outdoors whose feet are wet for excessive periods of time. It was nicknamed "trench foot" during World War I when soldiers forced to slog through mud in their boots developed the condition. If the conditions are right, immersion foot can even occur while indoors.

Symptoms of immersion include numbness and the whitening or reddening of the skin. This will eventually give way to pain, swelling, and the formation of blisters due to the maceration of skin. Like frostbite, symptoms may persist for weeks and cause long-term damage, including Raynaud's phenomenon (sudden cold and numb sensations) and neuropathy (shooting pain caused by nerve damage).

To treat immersion foot, clean and dry your feet, and either apply warm packs to your feet or soaking them in warm water (102° F to 110° F) for five to 10 minutes. When sleeping, do not wear socks.

Pernio (Chilblains)

Pernio, also called chilblains, is an inflammatory skin condition caused by over-exposure to cold (rather than freezing) temperatures. Pernio is caused by the formation of bumps and red- to violet-colored patches on the hands or feet due to an abnormal response of blood vessels. The affected areas can become puffy, itchy, and painful, with symptoms often persisting well after the skin is rewarmed.

This condition affects women more often than men and typically occurs in tandem with Raynaud's phenomenon and circulatory problems such as acrocyanosis and cold agglutin disease. On rare occasion, the lesions can lead to blistering or gangrene.

Pernio usually clears up on its own within one to three weeks, though it may recur for years. Treatment may also involve the use of heating pads and corticosteroid creams to relieve the itch and inflammation

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Article Sources
  • Irwin D.O., Brian. American Family Physician. A Case of Necrotic Toes. 2004 Feb 1;69(3):609-610.
  • Dockery, DPM, Gary L. and Crawford, DPM, Mary Elizabeth (Ed.). Cutaneous Disorders of the Lower Extremity. Philadelphia: W.B. Saunders, 1997. 128-29.
  • Centers for Disease Control and Prevention. Cold Stress.