Fever is a rise in body temperature above the normal temperature, usually caused by infection. Normal body temperature is around 37°C (give or take a degree, depending on individual differences). There may also be minor fluctuations over the course of the day and night. Contrary to popular belief, the severity of fever isn’t necessarily related to the seriousness of the illness – for example, life-threatening meningitis might only cause a small temperature rise.
The fever triggered by a viral or bacterial infection is caused by chemicals produced by the immune system, which reset the body’s thermostat to a higher level. Most cases of mild fever resolve by themselves within a couple of days. A mild fever (up to 39°C) can actually help the immune system to get rid of an infection. In children between the ages of six months and six years, fever can trigger convulsions. A fever of 42.4°C or higher, particularly in the elderly, can permanently damage the brain.
Symptoms of fever
The symptoms of fever can include:
Source: Better Health Channel: Fever