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 constrict, which is why our hands and feet get cold when the temperatures drop. Cold weather injuries such as frostbite are always a concern for winter outdoor occupations and recreational activities. These injuries can range from mild symptoms such as pain, to severe permanent damage that may require amputation of toes.
Types of Cold Injuries
- Frostnip — Frostnip is sometimes referred to as a mild form of frostbite, which occurs after brief exposure to freezing temperatures. Unlike true frostbite, no actual freezing of the skin or deeper tissues occurs, so frostnip usually causes no lasting damage once the feet have been warmed. Symptoms of frostnip include pain and skin color changes, such as whitening (blanching) or redness.
- Frostbite — Frostbite becomes a risk with exposure to freezing temperatures, at or below 32°F (0°C). Frostbite occurs when actual freezing happens within the skin, leading to varying degrees of damage. In the early stages of frostbite, symptoms are similar to frostnip: pale skin that becomes red and sometimes swollen upon warming. Numbness may also occur, which can make the area prone to further damage if one doesn't feel pain and get the appropriate first aid. If continued exposure to freezing occurs, frostbite damage can progress through the layers of skin and cause blistering (2nd degree frostbite). In third-degree frostbite, the damage progresses through the skin into subcutaneous tissues. Blisters are also seen and may be filled with blood. Fourth-degree frostbite involves gangrene of the affected area, inevitably requiring amputation of one or more toes.
It's important to recognize the symptoms of frostbite as early as possible. Cold, numb areas of the feet may also appear white or purple-ish and feel hard to the touch. The blistering and skin slough of second and third degree frostbite may last for days or even months, depending on the degree. Treatment of frostbite involves warming of the feet, while being careful to avoid excess heat or pressure against affected areas. It is best to elevate the affected limb and seek medical treatment as soon possible. More rapid warming measures, such as warm water soaks, may be provided by the medical team.
- Immersion Foot — Also known as trench foot, immersion foot occurs with exposure to cool, damp conditions. The symptoms of immersion foot can be similar to frostbite, except that immersion foot is characterized by prolonged exposure to non-freezing temperatures. If the conditions are right, immersion foot can even occur while indoors. Immersion foot can be a problem for those in cool weather occupations, where boots are worn and exposure to moisture is high. Initial symptoms include numbness and color changes such as whitening or reddening, eventually leading to pain, swelling, and possibly blister formation after the feet warm up. Like frostbite, symptoms may persist for weeks, and have long-term effects such as temperature changes (Raynaud's phenomenon) and shooting pain. As with frostbite, it's best to dry the feet and re-warm them as soon as possible. Medical attention should be sought if symptoms don't resolve with first aid.
- Pernio — Also called Chilblains, Pernio is another condition that can be brought on by over-exposure to humidity and coolness, not necessarily freezing temperatures. Pernio has characteristic skin lesions that are the result of damage to small blood vessels from cold exposure. The lesions usually occur on the toes and appear as red, puffy areas of skin. These areas can be painful and intensely itchy, and often persist after exposure. This condition affects women more often than men, and may occur again with future cold exposure. Rarely, the lesions can lead to blistering or gangrene. Treatment may involve corticosteroid creams to relieve itch and inflammation, possibly oral medications to improve circulation to affected areas, and wound care if necessary.
For more information, see: Protecting Your Feet from the Cold
Irwin D.O., Brian. American Family Physician. A Case of Necrotic Toes. Accessed 1/16/13. 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. Accessed 1/16/13.