Frostbite

First aid for frostbite

1. Get out of the cold into a warm place. Remove wet clothing and tight jewelry.
2. Check for hypothermia and treat that first. Call 911 or your local emergency number if the person is confused, very drowsy or has stopped shivering.
3. Do not rewarm if there is a chance the area will freeze again before reaching shelter or medical care. Refreezing after thawing causes much worse damage.
4. Avoid walking on frostbitten feet if possible, especially after thawing.
5. Rewarm in warm water, 37 to 39 °C (99 to 102 °F), which feels comfortably warm to an unaffected hand or elbow, for 15 to 30 minutes until the skin is soft and color and feeling return. Use a thermometer if available. Rewarming is often very painful.
6. If water is not available, warm the area with body heat, such as placing fingers in the armpits.
7. Do not rub or massage the area, rub snow on it, or use direct heat from heaters, fires, heating pads or hair dryers. Numb skin burns easily.
8. Take ibuprofen at the label dose, if safe for you, which may reduce pain and tissue damage.
9. Protect the area: loosely wrap with dry, sterile gauze, separate fingers and toes with gauze, and avoid breaking blisters.
10. Get medical care for anything beyond mild frostnip.

Stages of frostbite

Doctors also grade frostbite from 1 to 4 based on how far the damage extends after rewarming.

Causes and risk factors

Frostbite happens when skin is exposed to temperatures below freezing, especially with:

• wind chill: wind accelerates heat loss
• wet clothing or skin, including sweat
• contact with metal or cold liquids, such as fuel
• high altitude
• tight footwear or gloves that reduce circulation

People at higher risk include:

• outdoor workers, mountaineers, winter sports enthusiasts and military personnel
• people experiencing homelessness
• people who are intoxicated with alcohol or drugs
• people with diabetes, peripheral artery disease, Raynaud's phenomenon or neuropathy
• smokers
• older adults and young children
• anyone with a previous cold injury

Symptoms

• cold, prickling skin, then numbness
• red, white, bluish-white, grayish-yellow or purple skin
• hard or waxy-looking skin
• clumsiness from joint and muscle stiffness
• throbbing pain and swelling on rewarming
• blisters within 24 hours of rewarming

How doctors treat frostbite

In hospital

• Rapid rewarming in a warm water bath at 37 to 39 °C, with strong pain relief
• Blister care: clear blisters may be drained; blood-filled blisters are usually left intact
• Ibuprofen to limit inflammation
• Tetanus vaccination if needed
• Clot-dissolving medicine (tPA) or iloprost for severe deep frostbite, ideally within 24 hours, in specialist centers, to restore blood flow and reduce amputations
• Bone scan or MRI to assess blood flow and predict tissue survival

Later treatment

Dead tissue turns black and hard over weeks. Surgeons usually wait 1 to 3 months for the line between dead and living tissue to become clear before any amputation, unless infection develops. Physical therapy helps maintain movement.

Complications

• infection and gangrene
• loss of fingers, toes or other tissue
• long-term numbness, tingling, pain and cold sensitivity
• excessive sweating, nail and skin changes
• joint stiffness and arthritis
• growth problems in children when growth plates are damaged

Frostbite vs other cold injuries

• Hypothermia: a drop in core body temperature that affects the whole body and is life-threatening. It can occur with frostbite
• Trench foot: damage from prolonged cold and wet conditions above freezing
• Chilblains: itchy, red or purple swellings on fingers and toes after cold, damp exposure, without freezing

Prevention

• check weather forecasts and wind chill, and limit time outdoors in extreme cold
• dress in loose, layered clothing with a windproof, waterproof outer layer
• wear mittens rather than gloves, a hat covering the ears, a face covering and insulated, waterproof boots
• keep clothing dry, and change wet socks and gloves promptly
• avoid alcohol and smoking in the cold
• watch each other for pale or white patches on the face
• warm up at the first sign of numbness or tingling

Frequently asked questions

What are the first signs of frostbite?

The first signs are cold, tingling or prickling skin, then numbness, and skin that turns red, white or grayish-yellow. This early stage, frostnip, reverses fully with gentle rewarming. Hard, waxy skin that does not soften means deeper frostbite.

How long does it take to get frostbite?

It depends on temperature, wind and wetness. In very cold, windy conditions, exposed skin can freeze in under 30 minutes, and at wind chills below about minus 40 °F (minus 40 °C), in as little as 5 to 10 minutes.

How do you treat frostbite at home?

Get out of the cold, remove wet clothing and rewarm the area in warm water, 37 to 39 °C (99 to 102 °F), for 15 to 30 minutes, only if it will not refreeze. Do not rub it or use direct heat. Seek medical care for anything more than mild frostnip.

Will frostbitten skin heal?

Frostnip and superficial frostbite usually heal fully within weeks, sometimes with peeling and temporary sensitivity. Deep frostbite may lead to loss of tissue. Many people have lasting cold sensitivity, numbness or pain in the affected area.

What does frostbite look like?

Early frostbite looks red or pale. Deeper frostbite looks white, grayish-yellow or blue and feels hard or waxy. After rewarming, blisters may form, and deep frostbite can turn black over days to weeks.