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're 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 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 prickly pain and skin color changes, such as whitening (blanching) or redness.1
Frostnip can be treated by warming the skin. You can do so by bundling up in a warm towel pulled from a dryer or by soaking in warm—but not hot—water.
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.1
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.2 Even the ears and nose can be severely affected by frostbite. Depending on the damage incurred, treatment may involve:3
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 months after the injury1
Whirlpool therapy and/or physical therapy during rehabilitation
It's important to recognize the early signs of frostbite to avoid permanent injury. Seek warmth and shelter the moment numbed areas of your hands, feet, or ears begin to turn white or purplish and start feeling warm rather than cold.
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 the 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 the skin.2 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 5 to 10 minutes. When sleeping, do not wear socks.
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 men4 and typically occurs in tandem with Raynaud's phenomenon and circulatory problems such as acrocyanosis and cold agglutin disease. On rare occasions, the lesions can lead to blistering or gangrene.2