A local frostbite occurs, when a body part is exposed to the cold and the temperature drops so low that water in the tissues starts to freeze. The extent of a frostbite is difficult to estimate before it thaws. Small local and superficial frostbites can be easily treated at home.
In winter in Finland, frostbites are rather common, especially when the temperature drops below -20 degrees of Celsius. The risk of frostbite increases with wet clothes and wind. Also smoking and various illnesses and medications that affect the peripheral circulation may increase the risk of frostbites. Frostbites occur especially in the ears, nose, fingers, toes, and cheeks. When the temperature outside the body drops, circulation of the extremities decreases as the body attempts to maintain the core body temperature.
In superficial frostbites, the skin tingles and may feel numb. Gradually, the skin colour changes, the skin looks waxy and pale and feels hard to touch. As the skin gets increasingly numb, pain stops.
A so-called trench foot (immersion foot) may develop in prolonged exposure to cold and wet conditions, which leads to swelling and redness when the foot is warmed.
In deep frostbites, the subcutaneous tissue is also damaged. The skin feels numb and hard. You cannot put weight on the frostbitten limb and may lose grip strength. The skin may turn blue and swollen, and blister. The frozen area of skin may even become gangrenous following a severe cold injury. More severe cold injuries must always be treated in hospital without delay. Most of the tissue damage is caused by infection during thawing.
The best way to prevent frostbites is to dress in cold-proof and waterproof clothing and drink enough sugar-sweetened fluids. Keep moving as exercise helps maintain blood circulation to the extremities in cold conditions. Frost barrier creams and lotions are not recommended as, despite of their name, they may increase the risk of frostbites.
Small local and superficial frostbites can be treated at home. The important thing is to stay warm and sheltered from the wind. You can warm up the frostbite by gently pressing it with hand, but do not rub or massage the area.
The affected area should be rewarmed quickly by immersing it in warm water of 37°C to 42°C for 20 to 30 minutes. During bathing, normal skin colour and sensation should return and the hardness of the skin disappear. Do not warm the frostbitten area in front of an open fire, as this may lead to a burn. Cover the frostbitten area with dry clothing.
Warming the frostbitten area may be surprisingly painful. You can take over-the-counter anti-inflammatory medicine (e.g. ibuprofen) available at pharmacies, to relieve the pain. Pharmacy staff will help you select the right product, if necessary. Hot beverages are recommended. Avoid drinking alcohol and smoking during treatment.
You should seek medical advice, if
- the normal skin colour, sensation and temperature do not return in an hour.
- blisters appear on the skin
- the frostbitten area is large (such as a large part of a limb).
Emergency care professionals have produced the instruction in collaboration with Terveyskirjasto.