The symptoms of frostbite progress in 3 stages.
The colder the temperature and the longer the body is exposed to freezing conditions, the more advanced frostbite can become.
During the early stage of frostbite, you'll experience pins and needles, throbbing or aching in the affected area. Your skin will become cold, numb and white, and you may feel a tingling sensation.
This stage of frostbite is known as frostnip, and it often affects people who live or work in cold climates. The extremities, such as the fingers, nose, ears and toes, are most commonly affected.
After these early signs of frostbite, prolonged exposure to cold temperatures will cause more tissue damage. The affected area will feel hard and frozen.
When you're out of the cold and the tissue has thawed out, the skin will turn red and blister, which can be painful. There may also be swelling and itching.
This is known as superficial frostbite, as it affects the top layers of skin and tissue. The skin underneath the blisters is usually still intact, but treatment is needed to make sure there's no lasting damage.
When exposure to the cold continues, frostbite gets increasingly severe. The skin becomes white, blue or blotchy, and the tissue underneath feels hard and cold to touch.
Further damage may occur beneath the skin to tendons, muscles, nerves and bones. This is known as deep frostbite and requires urgent medical attention.
As the skin thaws, blood-filled blisters form and turn into thick black scabs. At this stage, it's likely that some tissue will die. This is known as tissue necrosis, and the affected tissue may have to be removed to prevent infection.
People with a history of severe frostbite often report further long-term effects of frostbite.
These can include: