Frostbite occurs when skin becomes frozen after exposure to climate conditions capable of severely lowering body temperatures. Any area of exposed or under-protected skin is susceptible to frostbite, though the cheeks, fingers, toes and nose are most commonly affected. Frostbite can happen within minutes. While early frostbite, called frostnip, is minor if caught early, prolonged cold exposure can result in more serious frostbite complications. Symptoms of prolonged frostbite may indicate how severely exposed skin has been affected.
Skin and Joints
Prolonged frostbite causes blood vessels to narrow and reduce blood supply to frostbitten skin. Skin may appear pale to white with a waxy sheen and may feel hard to the touch. Affected joints, such as fingers and toes, may ache and feel stiff and hard to flex.
Sensation Changes
Frostbite freezes nerve cells inside skin tissues and changes the way pain is experienced. A person with prolonged frostbite may initially feel stinging or burning in the frostbitten area, which progresses into total sensation loss. Upon re-warming of superficial frostbite, the affected area will begin to feel sensation, often prickly or painful. Re-warming of deeply frostbitten skin may not restore any feeling or sensation to the affected area.
Swelling and Blisters
Prolonged frostbite freezes cells inside body tissues and allows waste products to build inside the blood. When circulation returns to frostbitten skin during warming, toxins in the blood can cause blisters or ulcers on warmed, frostbitten skin. Blisters may contain clear fluid, or blood, which may indicate deeper frostbite according to Merck Manuals. Blisters may open and leave behind blackened areas of skin that resemble gangrene. "Sports Medicine for the Primary Care Physician;" Richard Birrer; 2004, advises that these areas of damaged skin often do not result in permanent tissue loss.
Gangrene
Deep frostbite completely freezes deeper body structures and can permanently damage skin, muscles, bone and tendons. Deeply frostbitten skin will appear white, cold and hard to the touch. Warming the affected area does not result in swelling or color change as blood circulation may be permanently damaged. Merck Manuals states that deep frostbite can then turn gray with a wet appearance, or black and leathery which indicate dead tissue, also known as gangrene. Gangrenous tissue from prolonged frostbite may need to be surgically removed to prevent further complications.
