Frostbite is an injury where a part of your body freezes. The frozen tissue dies and can't come back to life. Cold also can damage tissue without freezing it. This is called nonfreezing tissue injury.
See a doctor right away if you think you have frostbite.
Frostbite happens when very cold temperature freezes your skin. With severe frostbite, tissue under the skin freezes too.
Any cells that are frozen die. They don't come back to life after they're thawed. The dead tissue can get infected easily.
Nearby cells that aren't frozen can be damaged by the cold. They might survive if they're warmed up quickly but may still die later. It can take a long time to tell whether some tissue will survive.
You have a higher risk of getting frostbite if you're out in cold weather and:
Frostbitten areas are numb and feel cold to the touch. Other symptoms depend on how deep the frostbite goes.
When a frostbitten part warms up, it stops being numb and hurts a lot.
Any black, leathery skin eventually falls off. Sometimes your whole finger or ear falls off. This may not happen for a long time.
After frostbite heals, that part of your body is often very sensitive to cold. It may be permanently numb or painful. Your fingernails and toenails may not look right.
Doctors can tell if you have frostbite by examining you. Sometimes frostbite looks like nonfreezing tissue injury at first.
The quicker you warm up a frostbitten part, the better. If you can’t get to a hospital right away:
The warm water is the right temperature if someone else who doesn't have frostbite can keep a hand in it comfortably. Water that's too hot will damage your skin more.
If your feet are frostbitten and you have to walk to get to safety, it's better not to thaw them out first. It's worse to walk on thawed feet than to walk on frostbitten feet. And it's worse if your thawed feet freeze a second time.
Don’t do the following:
Doctors will warm your frostbite in warm water and will also:
Doctors try to wait as long as they can before doing surgery. Waiting lets them see whether tissue is dead or just badly damaged.