What is Frostbite?

Frostbite is a physical injury to skin and tissues caused by exposure to extreme cold temperatures or by contact with extremely cold objects (particularly metals). Frostbite occurs when skin and tissue temperature falls below freezing (0°C / 32F) and obstructs blood flow. Constricted blood vessels can be severely and permanently damaged and blood circulation may stop in the affected tissues.

In severe cases of frostbite, skin and tissues may be damaged without any pain being felt. Frostbitten skin is highly susceptible to infection and the development of gangrene (localized tissue death due to blood loss).

Signs & Symptoms

• Affects extremities first (i.e.: finger tips, ears, nose, toes)
• Change in skin colour from red to blue or white as symptoms worsen
• In severe frostbite, blisters may form or skin may turn black as necrosis (tissue death) sets in

First Aid for Frostbite

• Check for signs of hypothermia, and seek medical help if required.
• Assess and monitor ABCs (Airway, Breathing, Circulation).
• Do not attempt to warm the affected frostbitten areas directly.
• Do not rub the affected areas or apply dry heat.
• If possible, move the person indoors or to a warm, dry area.
• Remove wet clothing.
• Wrap the person in blankets or other dry materials to insulate against heat loss to the air and ground.
• Avoid direct heat, such as open flame or fire, which can burn the skin.
• If skin has become raw or blistered, loosely cover the affected area with a dry sterile dressing. Place gauze between the fingers and/or toes to absorb fluids and prevent sticking together.
• Provide warm, non-alcoholic, non-caffeinated beverages if safe to do so. Do not force oral fluids if the person is unconscious or convulsing.

Preventing Frostbite

Frostbite can be prevented by wearing proper clothing and footwear. Extremities such as hands, feet, ears, and nose are most susceptible to cold temperatures. Moisture reduces the insulating value of clothing, so it is important to choose the right garment for the activity. Cotton fibres retain moisture, therefore cotton socks should be avoided due to their retention of sweat. Wool and synthetic fibres are preferred to help wick and dissipate moisture from the skin.

Stay dry, seek shelter when needed, and be active/keep moving (without breaking a sweat) unless you need to preserve energy.

Adapted from:
Cold Environments - Health Effects and First Aid. CCOHS, Government of Canada.