Infection and hypothermia are the main complications of frostbite.

Hypothermia

Around 1 in 8 people with severe frostbite will also develop hypothermia.

Hypothermia occurs when a person's body temperature drops below 35C (95F). Initial symptoms can include:

• constant shivering
• tiredness
• low energy
• cold or pale skin
• fast breathing

Symptoms of severe hypothermia include:

• unconsciousness 
• shallow or no breathing
• weak, irregular or no pulse
• dilated pupils

Hypothermia is treated by preventing further heat being lost and by gently warming the patient. Seek immediate medical attention if you think you or someone else has severe hypothermia as it can be life threatening.

Read more about the treatment of hypothermia.

Infection

If some of your tissue dies, the dead tissue will no longer have a blood supply. This can make the affected body part very vulnerable to infection as your body relies on white blood cells to ward off infections.

Infections associated with frostbite include tetanus and more generalised bacterial wound infections.

More seriously, infection can spread into the blood (sepsis).

These conditions require admission to hospital and treatment with immunoglobulin in the case of tetanus and antibiotics in the case of sepsis.

Read more about treating tetanus and treating sepsis.