Your normal body temperature is approximately 37°C. A fever is usually when your body temperature is 37.8°C or higher. You may feel warm, cold or shivery.
You can find out if you have a fever by using a thermometer to take your temperature
What causes a fever?
A fever is your body’s natural response to many common illnesses such as:
Fever helps your body fight infections by stimulating your immune system (your body’s natural defence). By increasing your body’s temperature, a fever makes it harder for the bacteria and viruses that cause infections to survive.
When to get help
Contact your GP practice if:
- you have severe thirst or are peeing less
- you are passing urine that is darker than normal
- you are light-headed or weak
- you have new, severe muscle cramps
- your symptoms have worsened or you notice new symptoms
- you’ve had a fever after recent foreign travel
If your GP practice is closed, phone 111.
Contact your GP practice immediately if:
You have a fever and you:
- are on treatment for immune deficiency
- are on immune-suppressant drugs, such as regular steroids, methotrexate, azathioprine or cyclophosphamide
- are taking medication where you have been warned about a risk of a reduced immune system
- are on, or recently completed, treatment for cancer, leukaemia or lymphoma
- are a transplant recipient
- are HIV positive
- have chronic lung disease
- have asthma which has been treated with medication in the last 3 years
- have heart disease (excluding blood pressure which is currently well controlled)
- have diabetes or another metabolic disease
- have chronic gastrointestinal or liver disease
- have chronic renal (kidney) disease
- have cystic fibrosis
- have neurological conditions such as cerebral palsy, stroke, multiple sclerosis or muscular dystrophy
- have sickle cell disease
Treating a fever
Most fevers will improve on their own in a few days. However, there are a number of things you can do to help the uncomfortable feelings associated with a fever.
Do
- wear loose comfortable clothing
- make sure the room you are in isn’t too warm
- drink more fluids (for example water) so you don’t get dehydrated – you should be peeing approximately every 6 hours (a pale yellow urine means you’re unlikely to be dehydrated)
- avoid alcohol as this can make dehydration worse
- take a medicine that reduces fever such as paracetamol (unless you’re allergic or have been told by a healthcare professional that you can’t take it)
Don’t
- do not over dress
- do not attempt to make yourself feel cold
