Frostbite occurs when sub-freezing temperatures cause the blood vessels in the skin to constrict, which reduces the amount of blood and, therefore, oxygen transported.

The lack of oxygen may eventually destroy the cells, although this does not usually occur with frostbite. Extensive frostbite of the limbs may lead to hypothermia.

It is important to learn to recognize the signs of frostbite: numbness in the skin and the paleness of the area affected, which is hard to the touch. When you recognize these symptoms, you can react more quickly and thus avoid deeper frostbite, which may lead, within days of exposure to cold, to the formation of blisters similar to the ones caused by burns. Severe frostbite will turn the skin brown and cause a burning sensation as it heals. Do not worry; this is entirely normal.

The frostbitten area may be insensitive until it has completely healed. In very serious cases, sensitivity may be permanently altered.

When to consult a physician

Most frostbite is not serious and can be treated at home.

You should consult a physician immediately if:

• you have the shivers and your body temperature falls below 35ºc
• you experience a lack of coordination
• you are confused
• you have difficulty speaking
• you have blisters on the face, ears, or limbs
• your skin turns black or blue
• your skin remains frozen 30 to 60 minutes after being warmed
  

If you still have concerns or if you wish to obtain more information, dial 8-1-1 to contact Info-Santé.

Self-care

• Warm the frozen areas with warm, wet compresses or by soaking them in water that is initially at room temperature (22ºC to 24ºC) and is then gradually heated to 38ºC to 42ºC. Mild frostbite can be warmed up with heat from the hands. The skin should regain its normal colour and warmth.
• Do not attempt to warm up frostbitten areas too quickly – for example, by bringing them into contact with a direct heat source such as a radiator or hairdryer.
• Avoid rubbing the skin to warm it, since this may cause further damage.

Source: Santé et services sociaux - Québec (MSSS) [1]