Fever in children

• Normal temperature – your child's normal body temperature is about 37 degrees Celsius (37^o C).
• A fever – your child has a fever if their temperature is 38 degrees Celsius (38^o C) or higher.
• A high fever – this usually means more than 38.5 degrees Celsius (38.5^o C).

What the number on the thermometer can't tell you

Fever by itself doesn't tell you whether your child is seriously sick.

If your child is miserable and seems unwell, and feels hot, you can use a thermometer to take their temperature. You don't need to do this if your child seems well.

The number on the thermometer can't tell you:

• what's causing the fever
• how sick your child is.

Check how to use thermometers.

The most common cause of a fever in a child is a viral infection. A bacterial infection is a less common but more serious cause.

Your body's natural reaction to infection with a virus or bacteria is to raise the temperature inside your body. This helps to kill the infection.

Other causes of high body temperature include:

• immunisation – this usually causes only mild fever
• wrapping a baby in too many warm layers of clothing, or bedding.

Fever is a normal way for a child to fight an infection. Being hot may make your child feel unhappy or uncomfortable, but the high temperature is very unlikely to cause any long-term problems.

A small number of tamariki have seizures when they have fevers. Read more about febrile seizures.

If you're worried about your child, whether or not there is a fever, take them to see a healthcare provider.

If your child has already seen a healthcare provider but they're getting worse, go back to a healthcare provider.

Call Healthline on 0800 611 116 if you're unsure about what to do. 

When should I see a healthcare provider urgently?

See a healthcare provider urgently if your child with a fever:

• is under 3 months old – young pēpi (babies) need a different and more cautious approach
• looks unwell and you are concerned
• is very pale or feels cold to touch
• is floppy, sleepy or drowsy
• is becoming less responsive
• has an unusual high-pitched cry
• has trouble breathing, has noisy breathing or is breathing fast
• complains of a stiff neck or light hurting their eyes
• has a severe headache
• refuses to drink – even small sips
• vomits a lot and can't keep sips of fluid down
• vomits green fluid (bile)
• vomits blood – this may be red or brown
• is in severe pain
• is not interested in surroundings (lethargic).

When should I see a healthcare provider?

See a healthcare provider if your child with a fever:

• has a sore throat or joint pains
• is drinking less than half of their normal breastmilk or other fluid
• is having fewer than 4 wet nappies in 24 hours
• vomited half or more of their feed for the last 3 feeds
• has frequent and watery poo (diarrhoea)
• complains or cries when doing a wee
• is in pain
• is getting sicker
• is not improving after 2 days
• has had a fever for more than 5 days.

When is it OK to look after my child with a fever at home?

You can look after your child with a fever at home if they:

• are drinking and feeding well
• are still interacting with you
• don't look sick.

Is there anything I need to tell a healthcare provider about my child with a fever?

Tell the healthcare provider if your child:

• has been overseas in the last few weeks
• has been around someone who is unwell.

If your baby is less than 3 months old, they need a different and more cautious approach.

• They have a fever: If your baby has a fever, make sure to go to your doctor. Pēpi get fevers for the same reasons as older tamariki, but they are not as good at fighting off infections.
• They seem sick and you're worried: If you are worried about them, take them to a healthcare provider even if they don't have a fever.
• They seem cold: Some pēpi may have an unstable temperature with an infection. They may be colder than normal. In a sick baby this is a worrying sign and is a reason to see a healthcare provider urgently.
  
  

Image credit: Canva

Undress your child so that they are just wearing a single layer (maybe a singlet and pants). Make sure the room is not too hot or too cold. These are the best and most comfortable ways to bring your child's temperature down. It's best not to give your child a bath or shower to cool them. You could use a cool face cloth.

Your child may need extra rest or they may want to play – this is OK.

Encourage them to drink fluids and eat healthy small meals.

Medicines

If your child is happy, and they are not unwell, you do not need to do anything more. You do not need to treat the fever with a medicine.

Paracetamol

If your child is miserable because of the fever, you can give paracetamol to make them more comfortable. You must follow the dosage instructions on the bottle. It's dangerous to give more than the recommended dose. You can use a paracetamol dose calculator to find out how much to give them.

Other medicine

If your healthcare provider gives your child ibuprofen, use it only if your child with a fever is miserable. You can use an ibuprofen dose calculator to find out how much to give them. 

Don't give your child cold and flu medicines.

Never give your child aspirin as this may increase the risk of Reye syndrome, which is a rare and serious illness.