Fever factsheet


Your child’s body temperature can change depending on a range of different things like:

  • age
  • time of day
  • emotions
  • whether they are awake or asleep
  • how much they have been moving around
  • illness.

The average body temperature in children is between 36.5 and 38oC. 

A fever is when body temperature is over 38oC. Fever can be a sign that the body is fighting off illness or infection. 

The immune system raises your child’s body temperature to help the body work faster to fight illness and to make it harder for bacteria and viruses to live.

Fever is very common in children as they are at a higher risk of illness and infection.

Fever can be serious if it:

  • lasts longer than three days without going down
  • is high in a baby under three months old
  • causes a seizure.

Seizures caused by fever are called febrile seizures. They happen when fever disrupts your child’s regular brain activity.

 Signs and symptoms

A fever is usually found by checking your child’s body temperature by placing your hand on their forehead, then confirming by using a thermometer.

Your child will generally look unwell and feel very warm or hot. 

They might also be:

  • sweaty
  • shivering
  • shaking
  • chattering their teeth
  • flushed in the face.

Take your child to your local doctor or emergency department as soon as possible if they have a high fever and they:

  • are under three months old
  • have a bulging fontanelle, the soft spot on a baby’s head
  • have a chronic illness 
  • are undergoing treatment, like chemotherapy
  • are in pain
  • have difficulty swallowing
  • are struggling to breathe properly
  • develop a rash
  • have stiffness in the neck
  • are vomiting
  • have sensitivity to light
  • are unusually tired and irritable
  • have had a fever for longer than three days
  • have travelled overseas recently
  • have had contact with someone sick with a severe infection or illness.

If your child is older and has a fever because of a cold or flu, they can generally be managed at home.

Always speak to your doctor if you are not sure.


The doctor or nurse will use a thermometer to check your child’s temperature and confirm whether they have a fever. They may also do some tests to find out what is causing the fever.

Tests can include:

  • a physical examination
  • a blood test
  • a urine test
  • a swab of the nose and throat. 


Your child’s doctor will let you know if the fever can be managed at home or whether your child needs to be admitted to the hospital.

Mild fevers caused by a virus can usually be treated at home.

You can give over-the-counter pain relief like paracetamol or ibuprofen to treat a mild fever at home. Follow the instructions on the packet closely to find the correct dose for your child.

Over-the-counter pain relief will not cure the illness causing the fever, but it will give your child some relief from symptoms while they get better.

Never give a child aspirin to manage fever. Aspirin can cause severe and life-threatening illness in children.

You can also dress your child in light, cool clothing and encourage them to:

  • get lots of rest
  • drink plenty of fluids
  • avoid drinks that have sugar and caffeine
  • use a wet washcloth to cool down, rather than having a bath or shower.

Viral illnesses will usually get better on their own. Speak to your local doctor if your child does not get better or seems to get worse.

Children with fever caused by a bacterial infection may be given antibiotics by the doctor. Antibiotics are medications that kill off harmful, illness-causing bacteria.

Bacterial infection can cause serious illnesses, such as:


Taking your child’s temperature

Taking a child’s temperature can be tricky, especially when unsettled and unwell.

There are many different types of thermometers available to buy. Some digital ear and forehead thermometers may be easy to use but do not always give an accurate temperature reading.

A digital probe thermometer is the best type to use.

You can take your child’s temperature:

  • by mouth – placing the thermometer tip gently under the tongue and waiting until it beeps
  • under the armpit – placing the thermometer tip gently under the armpit and waiting until it beeps.

Clean the thermometer using warm, soapy water or alcohol-based sanitiser between each use.

Temperature taken from the rectum can be difficult and distressing for children. There is also a risk of damage to the rectum if your child is moving around too much while you try to take their temperature.

Your child may not like having their temperature taken and become very distressed. 

Tips to comfort children while their temperature is being taken include:

  • giving lots of comfort
  • explaining what you are doing
  • giving them lots of praise after you are finished.

When to seek help

Go to your nearest emergency department, or call triple zero (000) for an ambulance if your child has a high fever and:

  • has a seizure for the first time
  • is having trouble breathing
  • is blue around the lips.
Last updated Monday 25th March 2024


This factsheet is provided for general information only. It does not constitute health advice and should not be used to diagnose or treat any health condition.

Please consult with your doctor or other health professional to make sure this information is right for you and/or your child.

The Sydney Children’s Hospitals Network does not accept responsibility for inaccuracies or omissions, the interpretation of the information, or for success or appropriateness of any treatment described in the factsheet.

© Sydney Children’s Hospitals Network 2024