SummaryRead the full fact sheet
- Fever is a rise in body temperature, usually caused by infection.
- Fevers caused by viral illnesses shouldn’t be treated with antibiotics, since these drugs have no effect against viruses.
- High fever (about 41.5°C or more) is extremely dangerous and could trigger convulsions.
- Seek medical attention if you are concerned, particularly about fever in a child.
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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, but this can vary from person to person). There may also be minor fluctuations over the course of the day and night.
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.
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.
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 6 months and 6 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:
- feeling unwell
- feeling hot and sweaty
- shivering or shaking
- chattering teeth
- flushed face.
Infection is usually the cause of fever
The cause of fever is usually an infection of some kind. This could include:
- diseases caused by viruses – such as colds, flu, COVID-19 or other upper respiratory tract infections
- diseases caused by bacteria – such as tonsillitis, pneumonia or urinary tract infections
- some chronic illnesses – such as rheumatoid arthritis and ulcerative colitis can cause fevers that last for longer periods
- some tropical diseases – such as malaria, which can cause bouts of recurring fever or typhoid fever
- heat stroke – which includes fever (without sweating) as one of its symptoms
- drugs – some people may be susceptible to fever as a side effect of particular drugs.
Self-treatment suggestions for fever
Suggestions to treat fever include:
- Take paracetamol or ibuprofen in appropriate doses to help bring your temperature down.
- Drink plenty of fluids, particularly water.
- Avoid alcohol, tea and coffee as these drinks can cause slight dehydration.
- Sponge exposed skin with tepid water. To boost the cooling effect of evaporation, you could try standing in front of a fan.
- Avoid taking cold baths or showers. Skin reacts to the cold by constricting its blood vessels, which will trap body heat. The cold may also cause shivering, which can generate more heat.
- Make sure you have plenty of rest, including bed rest.
When to see your doctor for fever symptoms
You should always consult with your doctor in the following cases:
- You are still feverish after 3 days, despite home treatment.
- Your temperature is over 40°C.
- You are shivering and shaking involuntarily, or your teeth are chattering.
- You seem to be getting sicker as time goes by.
- You have unusual symptoms such as hallucinations, vomiting, neck stiffness, skin rash, rapid heart rate, chills or muscle spasms.
- You feel confused and drowsy.
- You have a severe headache that doesn’t respond to painkillers.
- You have recently travelled overseas.
When to seek immediate urgent medical attention
You should seek immediate medical attention if you or someone else has the following symptoms:
- fever with headache and a stiff neck
- rash that does not blanche to skin pressure (indicates bleeding into the skin) – this can be a sign of a life-threatening illness.
Since fever is a symptom and not an illness, the underlying cause must be found before specific treatment can begin. Some tests may be necessary if the cause of the fever is not clear after your doctor has taken a medical history and performed an examination. These tests may include:
- blood tests
- urine examination and culture
- throat swabs or mucus sample examination and culture
- stool examination and culture
Treatment depends on the cause – for example, chronic tonsillitis may require surgery to remove the tonsils (tonsillectomy).
Fevers caused by viral illnesses shouldn’t be treated with antibiotics, since these drugs have no effect against viruses. In cases of mild bacterial infection, it is usually best to allow your immune system to handle the problem, rather than take antibiotics.
Fever in children
On average, a child has up to 10 infections per year.
Body temperature isn’t a reliable indicator of illness for babies and young children – a child may have a mild temperature according to the thermometer (slightly over 37°C), but seem happy and healthy.
See a doctor right away if your child:
- is aged six months or less
- has a rash
- has a fever of 40°C or more
- is still feverish after a day or so, despite 4-hourly doses of baby paracetamol
- vomits or has persistent diarrhoea
- refuses food or drink
- cries inconsolably
- seems listless, floppy or just looks ill
- convulses or twitches
- has trouble breathing
- is in pain.
If you feel at all worried or concerned at any stage, consult with your doctor.
Using a thermometer
If you suspect that your child has a fever, you can use a thermometer to measure their temperature. Remember, though, that body temperature is better used as a guide than a reliable indicator of illness for babies and young children – a child might have a mild temperature according to the thermometer (slightly over 37°C), but may seem happy and healthy.
There are several types of reliable thermometers available, which come with instructions on how to use them. They are available from a chemist. If you are in doubt about which one to choose for your child, or have questions about how to use it, ask your pharmacist to explain.
Treatment for fever in children
- Dress your child in light clothing.
- Give drinks of clear fluid (like water).
- Keep your child cool.
- Give paracetamol in the correct dose for the child’s age (but not more than 4 doses in a 24-hour period). Do not give regular paracetamol medicine for more than 24 hours without seeking advice from your doctor.
- See your doctor if your child is 3 months or younger.
- Don't give your child a cold bath.
Fever can cause convulsions
A febrile convulsion is a fit or seizure that occurs in babies and children when they have a high fever, usually from an ear infection or a viral upper respiratory infection. The fit can last a few seconds or up to 15 minutes, and is followed by drowsiness.
Approximately 3% of otherwise healthy children will have one or more febrile convulsions between the ages of 6 months and 6 years. A febrile convulsion is not epilepsy and does not cause brain damage. There is no way to predict who will be affected or when this will happen.
The symptoms of febrile convulsion include:
- loss of consciousness (black out) – the child will fall if standing and may pass urine
- twitching or jerking of arms and legs
- breathing difficulty
- foaming at the mouth
- going pale or bluish in skin colour
- eye rolling, so only the whites of their eyes are visible
- your child may take 15 minutes to wake up properly afterwards – they may be irritable and appear not to recognise you.
Convulsions are rarely serious. If your child has a convulsion you should:
- Try to stay calm and don't panic.
- Place your child on the floor and remove any objects they could knock against.
- Don’t force anything into your child’s mouth.
- Don’t shake, slap or try to restrain your child.
- Once the convulsion has stopped, roll your child onto their side, also known as the recovery position. If there is food in their mouth, turn their head to the side, and do not try to remove it.
- Note what time the fit started and stopped, so you can tell the doctor.
- Have your child checked by your local doctor or nearest hospital emergency department as soon as possible after the fit stops to find the cause of the fever.
- Call triple zero (000) for an ambulance if the fit lasts more than 5 minutes.
Where to get help
- In an emergency, always call triple zero (000)
- Emergency department of your nearest hospital
- Your GP (doctor)
- Maternal and Child Health Line Tel. 13 22 29(24 hours, 7 days)
- NURSE-ON-CALL Tel. 1300 606 024 – for expert health information and advice (24 hours, 7 days)
- Fever in children, The Royal Children's Hospital Melbourne.
- Febrile seizures, The Royal Children's Hospital Melbourne.
- Fever – febrile convulsions, The Sydney Children’s Hospitals Network.
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