What is frostbite?

Frostbite develops when the skin freezes after being exposed to very low temperatures. Frostbite can cause serious permanent damage. With proper preparation, however, you can greatly reduce your risk of developing frostbite.

How does frostbite happen?

In temperatures below 0.5 degrees Celsius, the skin freezes and ice crystals form in the tissue, damaging the cells. Blood flow to the affected area slows and can stop. Frostbite can also happen with prolonged exposure to temperatures below 2 degrees Celsius.

Frostbite usually affects exposed areas such as the fingers, toes, ears, nose, cheek and chin.

Who is at risk?

Among those most at risk are:

• mountaineers, hikers or people doing extreme sports in the snow or at altitude
• homeless people
• people with poor blood circulation, such as those with diabetes
• military personnel on field exercises
• people who work outdoors

What are the symptoms of frostbite?

The first sign of frostbite is a cold, prickling feeling in the skin, followed by numbness.

At first, it's not painful, but as frostbite develops:

• the skin colour changes to mottled or white
• your skin becomes waxy or hard
• the skin becomes waxy or hard
• there is pain, pins and needles or numbness
• blisters or swelling may appear

People with frostbite may become clumsy and they may not be aware of their condition. If someone tells you your skin looks odd, you should take notice.

With severe frostbite, tissue below the skin becomes frozen. The joints and muscles may stop working. If untreated, the frozen skin and the tissue beneath it turns black and dies.

If you don't get warm, you could develop hypothermia.

When should I see my doctor?

Seek medical help immediately for moderate to severe frostbite. Call triple zero (000) for an ambulance or for other emergency services. Outside Australia, calling 112 (the international emergency number) will connect you with local emergency services in many countries.

If at all possible, don’t walk on frostbitten toes or feet — it can make them worse.

How is frostbite diagnosed?

Your doctor can confirm whether you have frostbite by talking to you and examining you. There are no specific tests.

If the frostbite is severe, you might need x-rays or scans to check for damage to deeper tissues.

How is frostbite treated?

If your frostbite is only mild, you may be able to can treat it yourself. Put the affected area in water that feels only slightly warm to the touch (around 40 to 42 degrees Celsius) for 15 to 30 minutes. You can take painkillers to help ease the pain. Don’t use direct heat or hot water, and don’t massage the area — these can all cause further damage. Seek medical help if the area blisters.

If you have moderate to severe frostbite, you should see a doctor get professional help as soon as possible. They will warm the frostbitten area slowly, and you will need painkilling medication for pain relief. The area may blister as it warms.

Once the area is thawed, it will be wrapped in sterile dressings. Elevate the affected limb to reduce swelling. You might need to wear a splint or brace.

If you have severe frostbite, you’ll probably be admitted to hospital and might be treated in a burns unit, because frostbite causes a type of injury that is similar to a burn. Recovery can be slow.

If the frostbitten area develops gangrene because the flesh has died, treatment could include:

• removal of damaged, dead or infected tissue
• surgery or even amputation of the damaged area
• medication, including antibiotics to fight infection

Can frostbite be prevented?

Be prepared — frostbite can occur in a few minutes if the temperatures are extremely low. You can help prevent it by:

• planning any trip
• dressing in layers of warm clothing, including a wind-resistant jacket, waterproof boots, gloves and hat
• wearing a scarf pulled up to cover your nose, mouth and ears
• limiting the time you spend outdoors in cold weather
• trying to stay dry and changing wet clothes if possible
• sheltering in a warm place when you can

If you are outdoors and your hands are getting frostbitten, warm them by tucking them under your armpits. Try to cover frostbitten ears, nose and exposed parts of your face with anything you can.