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Fever in babies
Key facts
What is a fever?
A fever is when your baby's body temperature rises to 38°C or higher.
A fever in babies is usually a sign of illness.
What symptoms are related to a fever in babies?
Symptoms associated with a fever in babies can include:
- feeling hot to touch
- looking pale and seeming unwell
- being irritable
- being more sleepy than usual
- not drinking or feeding as usual
- shivering
If your baby has a fever, other signs they are unwell can include:
- mottled skin
- a weak or high-pitched cry
- fewer wet nappies than usual
- a rash
Sometimes babies and young children can have a seizure when their temperature rises suddenly — this is called a febrile seizure.
What causes a fever?
A fever is your body's response to infections and some illnesses.
An infection with a virus is the most common cause of fever in babies and children. Infections with bacteria are another common cause of fevers.
Infections that can cause fevers in babies include:
Babies can also have a fever after having vaccinations.
Teething does not cause a fever.
How to take your baby’s temperature
Using a thermometer is the best way to check your baby's temperature.
There are several different types of thermometers.
Digital probe thermometers can be used in your child's mouth (orally) or under their armpit (axillary). In babies younger than 3 months old, it's best to use this type of thermometer under their arm.
Digital ear thermometers are quick and easy to use but may give a less accurate reading if not used properly. These thermometers are recommended for children older than 3 months.
Digital temporal artery thermometers use infrared scanning of your child's forehead. These thermometers are easy to use but are not always accurate.
Mercury thermometers are no longer recommended as they can break and poison your child. Fever strips and digital pacifier thermometers are also not recommended as they are not very accurate.
Your doctor, child nurse or pharmacist can show you how to use your thermometer properly.
If your child's forehead or skin feels very hot, it's a good idea to use a thermometer to take their temperature accurately.
How is the cause of a fever diagnosed?
Your doctor will ask about your baby's symptoms, how high their fever has been and how long they have been unwell.
They may also ask:
- if anyone else in your household is unwell
- if you have recently been travelling with your baby
- if your baby has had a recent vaccinations
- if your baby has been taking any medicines
They will examine your child and check their temperature. They will look for the cause of the fever.
Depending on your baby's age and how unwell they seem, your doctor may organise some tests. These may include:
- blood tests
- a urine test
- a nose or throat swab
- a chest x-ray
When should I see my doctor?
If your baby is under 3 months old and has a fever, you should take them to the hospital emergency department immediately, even if they are not showing any other signs of being sick.
If your baby is over 3 months, see a doctor if they have a fever and:
- have trouble breathing
- become drowsy
- don't want to drink and aren't weeing enough
- vomit repeatedly or have frequent episodes of diarrhoea
- display signs of a stiff neck, persistent headache or light hurting their eyes
- don't improve in 48 hours
- are in pain
Handy guide to what to do if your baby has a fever.
You know your baby best. At any stage if you're worried that your child is seriously unwell seek medical care immediately.
If you're baby or child are not well and you are not sure what to do, call healthdirect on 1800 022 222 to speak to a nurse.
For general advice you can also call Pregnancy, Birth and Baby to speak to a maternal child health nurse on 1800 882 436. Available 7am to midnight (AET), 7 days a week.
How is fever in babies treated?
Treatment of fever in babies depends on:
- their age
- the cause of the fever
- how unwell they are
Babies younger than 28 days with a fever need hospital treatment with antibiotics. Older babies may also need hospital treatment if they are unwell.
Your doctor may recommend self-care treatments for your baby at home.
Feeding and fluids
For breastfed babies younger than 6 months, offer extra breast feeds.
For formula-fed babies younger than 6 months, offer the usual amount of formula.
For babies older than 6 months, continue breastfeeding or bottle-feeding. You should also offer frequent, small drinks of water or oral rehydration solutions. You can buy oral rehydration solutions from the pharmacy or supermarket.
Don't worry if your child doesn't feel like eating (but do worry if they're not drinking).
Cooling measures
Dress your baby so that they are not too hot or cold. For children who are shivering, you can add a layer of clothing or a blanket until they stop shivering.
You can try cooling your baby down by wiping your baby's forehead with a sponge or face washer soaked in slightly warm water.
Cold baths and showers are not recommended for babies and children with a fever.
Medicines
If your baby has a fever, you can give paracetamol for comfort. Babies older than 3 months can also have ibuprofen for fever.
Make sure to follow the correct dose on the package.
Never give aspirin to children.
Resources and support
Talk to your doctor or child health nurse if you have questions about fever in babies.
The Royal Children's Hospital Melbourne has information on fever in children, available in languages other than English.
The Sydney Children's Hospitals Network also has a factsheet on fever, available in different languages.
Speak to a maternal child health nurse
Call Pregnancy, Birth and Baby to speak to a maternal child health nurse on 1800 882 436 or video call. Available 7am to midnight (AET), 7 days a week.
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Last reviewed: December 2024