Fever

Key points about fever in children

• a viral infection (such as a cold) is usually the cause of a fever in tamariki (children)
• if your child looks unwell and you are worried, take them to a health professional whether they have a fever or not
• if your child has already seen a health professional but they are getting worse, see a health professional again
• if your baby with a fever is under 3 months old, you should always see a health professional

What is fever?

Normal temperature

Your child's normal body temperature is around 37 degrees Celsius.

A fever

Your child has a fever if their temperature is 38 degrees Celsius or higher.

A high fever

A high fever usually means more than 38.5 degrees Celsius.

What the number on the thermometer can't tell you

Fever by itself does not 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 cannot tell you:

• what is causing the fever
• how sick your child is

Check out how to use thermometers

What causes fever in children?

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.

The body's natural reaction to infection with a virus or bacteria is to raise the temperature inside the 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

Will a fever harm my child?

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 about febrile seizures

When should I seek help for my unwell child?

If you are worried about your child, whether or not there is a fever, take them to see a health professional.

If your child has already seen a health professional but they are getting worse, go back to a health professional.

Call Healthline on 0800 611 116 if you are unsure what you to do.

When should I call 111?

Call 111 within New Zealand (use the appropriate emergency number in other countries) and ask for urgent medical help if your child:

• has blue lips and tongue
• has severe difficulty breathing
• has any episodes of irregular or stopping breathing
• has a worrying rash especially one that does not go away when you press on it
• is unconscious or you can't wake them up properly

See KidsHealth's page on meningococcal disease for photos of a worrying rash. 

When should I see a health professional urgently?

See a health professional 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 cannot 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 health professional?

See a health professional 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
• do not look sick

Is there anything I need to tell a health professional about my child with a fever?

Tell the health professional if your child:

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

What if my baby is less than 3 months old?

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 health professional even if they do not 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 health professional urgently.

How do I treat a fever in my child?

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 is dangerous to give more than the recommended dose.

Other medicine
If your health professional gives your child ibuprofen, use it only if your child with a fever is miserable.

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.