Frostbite prevention and treatment

What is frostbite?

When you expose your body to the cold for a long period of time, the blood flow to your hands, feet, nose and ears restricts. The combination of poor circulation and extreme cold can lead to frostbite.

Frostbite generally occurs in body parts farthest from the heart. It most often affects hands, feet, nose and ears.

How does frostbite happen?

Frostbite is a combination of frozen tissue, inflammation, blood clotting and impaired circulation. When we treat it, we try to counteract these processes.

If the cooling is rapid, ice crystals form, either around the tissue or inside cells. The ice prevents the transport of water and electrolytes or salts in and out of cells. This releases chemicals that cause inflammation. This affects your circulation and the blood supply becomes restricted. Frostbite injury is worse if body parts freeze, and then are rewarmed and then refrozen.

Who is at risk?

  • Outdoor adventurers.
  • Anyone who is not prepared for cold weather.
  • People who get stranded in the cold (such as in motorized vehicle failure).
  • Homeless people.
  • Outdoor workers.
  • People with diabetes or other conditions that affect circulation.
  • Infants (under 1 year).
  • Seniors (65 years or older).

Exhaustion, dehydration, malnourishment, existing medical conditions or impairment increases the risk of frostbite. They affect your body's ability to respond to colder temperatures. Alcohol also dilates the blood vessels and increases heat loss.

Alcohol and cold weather are not good companions. Substance use affects your ability to perceive your environment. Make sure you can trust your judgment to protect yourself or seek warmth and shelter.

When should I treat frostbite?

Most people are familiar with burn levels. It’s very similar for frostbite.

1st degree frostbite

This stage is mild and your skin will appear yellowish but is still soft to the touch. You might have some numbness and slight swelling. Your skin may turn red during the warming process but normal colour returns once the area warms.

2nd degree frostbite

This stage of frostbite results in blisters. The blisters are clear and the skin underneath heals well once the blisters slough off.

3rd degree frostbite

This stage results in darker blisters containing blood. Your skin forms a tough black covering that lasts several weeks. It can cause permanent damage to body tissue if you do not get it treated immediately. Nerve damage can occur if frostbitten skin becomes discoloured or black.

4th degree frostbite

This is the most severe stage of frostbite. It involves muscle and bone freezing. A black mummified appearance can affect your fingers, toes, ears and nose. The risk of amputation increases with this degree of frostbite.


What are the treatments?

Windburn

Do not scratch or rub the affected area – it can damage your skin. Apply moisturizer to help relieve the symptoms of windburn. You can also use a lip balm to protect your lips.

Frostbite

Mild frostbite (frostnip)

Passive warming

Move to a warm room, wrap yourself in blankets or reheat your body by skin-to-skin contact with another person.

Active warming

Add heat sources to the frostbitten area. The idea is to thaw the injured skin without burning yourself. Immerse your skin in water that's just above body temperature. You can also put your fingers into armpits. Do not rub, massage or shake the injured skin because that can cause more damage.

In both cases, remove any wet clothing you can and try to keep your body core warm and dry.

Severe frostbite

Severe frostbite requires immediate medical attention. While you're waiting for help to arrive begin treating it with passive and active warming. If your feet are frostbitten, you should not walk on them. You can damage them further and you may not have a proper pain response to prevent other injuries.

Do not rewarm the hands or feet or affected area unless you know you can keep them warm. You do not want those areas to refreeze. It is better to keep them cold until you are in a safe, warm place.

Hypothermia

People who have frostbite can often also have hypothermia, which is when your body loses heat faster than it can produce heat. Severe cases of hypothermia need immediate medical attention. Call 9-1-1 or your local emergency number.

For mild cases or while you're waiting for help to arrive for more severe hypothermia you can:

  • find shelter;
  • keep your muscles moving;
  • dry and warm your body slowly;
  • wrap yourself in blankets or dry clothing or reheat your body by skin-to-skin contact with another person;
  • drink warm, sweet liquids; and 
  • let your body shiver, this is one of the ways your body increases its core temperature.

If you're with someone who is unconscious, lay them down and avoid shaking them or handling them roughly. They may have an arrhythmia (irregular heart beat).

How can I reduce risk?

Stay indoors or protect yourself

  • Wear appropriate clothing to keep your core warm by dressing in layers with a wind-resistant outer layer.
  • Wear materials (such as synthetics and wool) that wick moisture away from your skin in insulation.
  • Keep extremities warm, including your nose – wear a scarf to protect it.
  • If you get wet, change into dry clothing as soon as possible.
  • On sunny days wear sunglasses, lip balm and sunscreen to protect your skin.
  • wear a face mask and goggles if you're participating in winter activities.
  • Keep moving (especially your hands and feet) to keep your blood flowing and maintain your body heat.
  • Inform others about where you are going and how you're travelling. This is as important for a mountain expedition, an ultra-race or getting home from a party on a cold night after a few drinks.
  • Know the weather conditions and wind chill alerts.
  • If you're in extreme cold conditions, look for shelter, such as a building, small cave, ditch, vehicle or anything that can help reduce your chances of frostbite or hypothermia.

You can prevent frostbite with good preparation, good clothing and common sense. For higher grades of frostbite, treatment is available that could save your toes and fingers. Make sure you get the proper medical care for your injuries.

References and other sources

Frostbite and children
Extreme cold