Injuries caused by exposure to cold are called frostbite. Frostbite can be local or systemic (frozen state), often caused by cold, dampness, and tight clothing or shoelaces. It commonly occurs in the skin, hands, feet, fingers, toes, ears, and nose.
Frostbite is divided into four degrees. First-degree frostbite is the mildest, also known as common "chilblains." The damage is confined to the epidermis. The affected skin appears red, swollen, and congested, with sensations of heat, itching, and burning pain. Symptoms disappear after a few days, and after healing, only the epidermis peels off without leaving scars. Second-degree frostbite affects the superficial layer of the dermis. In addition to redness and swelling, it is accompanied by blisters, which may contain bloody fluid. Deep edema, severe pain, and numbness of the skin may occur. Third-degree frostbite involves the full thickness of the skin, appearing black or purple-brown, with a loss of sensation. It is difficult to heal, and besides leaving scars, it may cause long-term hypersensitivity or pain. Fourth-degree frostbite affects the skin, subcutaneous tissue, muscles, and even bones, leading to necrosis and loss of sensation. Scarring may form after healing.
For treatment, it is first necessary to move away from the cold environment, remove damp clothing, and gradually re-warm in warm water. For systemic severe frostbite, artificial respiration may be necessary to enhance cardiac function, combat shock, and replenish fluids. For chilblains, besides re-warming and massage, rubbing with alcohol or chili water is effective, or applying 5% camphor alcohol and various chilblain ointments can also be beneficial. If blisters are present in second-degree frostbite, they can be punctured with a sterile needle to drain the fluid, followed by application of chilblain ointment. Third and fourth-degree frostbite require rescue and treatment under warm conditions.
The prevention of frostbite mainly involves keeping warm and enhancing cold resistance.