What is deep frostbite?

Deep or severe frostbite occurs when body tissues freeze. Deep frostbite usually affects fingers, toes, ears, nose, cheeks and chin, and can involve the deep structures including:

- Skin

- Fat

- Muscle

- Ligament

- Tendon

- Bone

- Blood vessels

- Nerves

Deep frostbite can lead to tissue death (necrosis) and gangrene. As the area starts to thaw, small ice crystals melt causing blood to rush back into the area. This leads to severe swelling and blistering. Blisters of deep frostbite commonly fill with blood (hemorrhagic blisters). The involved skin may appear bluish-black and feel hard.

Deep frostbite commonly has associated damage to muscles, tendons, ligaments and nerves. This may lead to problems such as:

- Loss of flexibility and movement

- Paralysis

- Contracture

- Chronic pain

- Sensitivity to cold

Deep frostbite can also lead to infection, which can damage affected body tissues and may require amputation if severe.

Deep frostbite is a medical emergency. Seek immediate medical attention if you think you have it.