What is frostbite?

Frostbite is an injury to your skin and tissues underneath. It happens when your skin freezes after being exposed to very low temperatures.

This can happen at or below 0 degrees Celsius (°C). Frostbite can happen more quickly in extremely low temperatures.

Being exposed to low temperatures can also cause other problems like hypothermia and chilblains.

What are the symptoms of frostbite?

The first sign of frostbite is pain. You will then notice numbness in the affected area.

If your hands and feet are affected by frostbite this can affect your movement and balance.

Your symptoms of frostbite will depend on how severe it is and how much skin and tissue are damaged underneath.

Frostnip

Frostnip happens before frostbite develops. Your affected skin may become:

• red and pale
• cold
• slightly painful
• tingly

Superficial frostbite

This is when only the surface of your skin has frostbite. Superficial frostbite can cause pins and needles and swelling around the area. Your skin may become:

• pale, yellow, or purple
• waxy
• numb

With moderate frostbite, large, clear blisters will develop. They will eventually dry out and your skin may peel.

Deep frostbite

Deep frostbite is severe. It affects tissues under the skin such as your:

• muscles and tendons
• bones
• nerves

Deep frostbite can cause blood blisters. Your affected skin may turn black.

What causes frostbite?

In cold temperatures your blood vessels become narrower. This reduces the flow of blood and warmth around your body.

At temperatures below 0°C your skin and tissues under the skin freeze. This causes ice crystals to form, damaging your cells. This can stop blood flow to the area and cause frostbite.

Frostbite can affect any part of your body. It's most likely to affect exposed areas like your cheeks and chin, or your extremities. Extremities are parts of your body furthest away from your core, such as your:

• fingers
• toes
• ears
• nose

Who is at risk of developing frostbite?

Anybody can develop frostbite. You are at a higher risk of developing frostbite if you:

• are a baby, young child, or aged over 75 years
• have poor blood circulation due to a condition such as diabetes
• participate in cold weather activities like skiing or hiking
• work outdoors
• have a disability or cognitive impairment
• are homeless

When should I see my doctor?

If you are concerned that you have frostbite, see a doctor.

When to seek urgent care?

Call triple zero (000) immediately and ask for an ambulance or go to the hospital emergency department if you've been exposed to very cold temperatures and:

• have hard, frozen skin
• have swelling and the affected area is numb
• have blisters
• are constantly shivering
• have slurred speech
• are breathing slowly
• are tired and confused

How is frostbite diagnosed?

Your doctor can diagnose frostbite by examining you and asking about your exposure to cold weather.

If your frostbite is severe you might need an MRI scan to check your tissue damage.

How is frostbite treated?

Treatment of frostbite depends on how severe it is. Your doctor will assess your situation and decide if you need to go to hospital for treatment.

First-aid for mild frostbite

If you have frostbite the first thing to do is find a warm, dry place. Remove any wet clothing and jewellery. Follow basic first aid and the steps below:

1. Put the entire affected area in warm water — this should be around 40 to 42°C.
2. Keep the area in the water until your skin turns pink, becomes soft to touch or does not improve any more — this can take up to 40 minutes.
3. Cover the area with a clean, light dressing — plastic cling film can be used.

Rewarming a frostbitten area can be painful and you can take pain medicine to help ease the pain.

It's important to prevent any more damage to the area:

• Don't use direct heat or hot water on the area.
• Don't massage the area.
• Avoid walking on frostbitten toes or feet.

If a frostbitten area refreezes, this can cause more damage. Only rewarm the area when you are in a warm dry place.

If your frostbite is only mild, you may not need further treatment.

Do not break any blisters that form.

Treatment of moderate or severe frostbite

Your doctor will:

• warm the frostbitten area slowly
• give you medicines to help manage your pain
• manage and clean your wound

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

If you have severe frostbite you will need to go to hospital. You may need treatment in a burns unit. This is because frostbite causes an injury that is similar to a burn. Recovery can take several months.

What are the complications of frostbite?

Frostbite can cause many complications including:

• chronic (long-term) pain in the affected area
• joint stiffness
• gangrene (death of body tissue due to lack of blood supply to the tissue)
• infection of the affected area and sepsis

You may be given antibiotics if your wound becomes infected.

If your frostbite wound has a serious infection, treatment may include removing the affected tissue with surgery. In severe cases this can involve amputation of the damaged area.

Sepsis is a medical emergency. If you suspect you or someone else has sepsis, call triple zero (000) and ask for an ambulance, or go to your nearest hospital emergency department.

Can frostbite be prevented?

If you are outside in extreme cold, you can protect yourself from frostbite. Here are some tips to prepare for cold conditions:

• Limit exposure to very cold weather — make sure you have warm shelter.
• Stay dry — wet clothing can lower your body temperature quickly.
• Keep up your energy — make sure you have food and can keep hydrated.
• Dress warmly with layers — this might include a wind-resistant jacket, waterproof boots, gloves, and covering your head, nose, mouth and ears.
• Avoid tight clothing, jewellery or footwear — these can limit blood flow.

Be aware of the early signs of frostbite. Don't ignore numbness or pain — take steps to get warm and find shelter.

Resources and support

Visit St John Ambulance Australia to learn more about first aid treatment of frostbite.

You can also learn more about frostbite on the NSW Health website.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.