Fever is a common symptom- and it can cause a lot of worry. There are a few questions patients commonly ask doctors when they have a high temperature- what it means and what to do about it. So, here are a few facts and figures to make matters a little clearer:

What controls body temperature?

A part of the brain called the hypothalamus controls body temperature- basically it’s the body’s thermostat- and it can reset the body to a higher temperature during infection and other illnesses

So does this mean I shouldn’t treat a fever with medication every time?

While a fever may be a useful defence against infection, research suggests that treating a fever with medicine such as paracetamol doesn’t make a difference to the overall outcome. Your doctor is likely to advise a common sense approach. So, if you have a fever and are feeling out of sorts, these medicines are worth trying and may make you feel more comfortable. But if you have a low grade fever and feel reasonably well, no treatment is necessary.

Does a higher fever always mean a more severe illness is present?

Not necessarily. Doctors always try to look at the bigger picture. A person can have a very high fever with a viral illness which will settle by itself, or they might have a milder fever but have a more serious illness! The history and examination usually clarify matters. The important thing is to see a doctor if you feel quite unwell, or if a fever is not settling after a few days.

Can anything other than infection cause a fever?

Yes, though it’s very rare indeed. These unusual causes include blood clots, cancer, or side effects of certain medications. Also, the body can overheat if the external surroundings are too hot leading to hyperthermia or “heat stroke”. This is different from a fever- in a fever the body sets its own thermostat at a higher level, whereas in hyperthermia outside factors (such as hot weather) cause the rise in temperature.