HealthInfo West Coast-Te Tai Poutini

Overview of fever (high temperature) in children

Tirohanga whānui ki te karawaka (paemahana teitei) ki ngā tamariki

Fevers are common in tamariki (children). A fever by itself does not tell you if they are seriously sick. Even an ordinary cold can cause a high fever.

Your child's normal body temperature is around 37°C. Your tamaiti has a fever if their temperature is higher than 38°C. A high fever usually means more than 38.5°C.

If your tamaiti is miserable, seems unwell and feels hot, you can use a thermometer to take their temperature. You do not need to do this if they seem well.

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

Other causes of high body temperature include:

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

Fever is a normal way for a tamaiti to fight an infection. 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.

Being hot may make your tamaiti feel unhappy or uncomfortable. But the high temperature is very unlikely to cause any long-term problems.

Some tamariki have convulsions (called febrile convulsions) when they have fevers. These look very worrying, but even these febrile seizures are very unlikely to cause long-term problems.

Getting help for your child with a fever

If you are worried about your tamaiti, whether or not they have a fever, you should take them to see a doctor.

If they have already seen a doctor but are getting worse, go back to your doctor.

Tell your doctor if your tamaiti has been overseas in the last few weeks or has been around someone who is unwell.

See a doctor urgently if the tamaiti with a fever:

is under 3 months old 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, 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 is not weeing vomits a lot and cannot keep sips of replacement drinks down vomits green fluid (bile) vomits blood – this may be red or brown or look like coffee grounds if it is not fresh is in severe pain is not interested in surroundings (lethargic).

See a doctor if the tamaiti with a fever:

has a sore throat or joint pains is drinking less than half their normal breast milk or other fluid is having fewer than 4 wet nappies in 24 hours has vomited half or more of their feed for the last 3 feeds

has frequent and watery poo (diarrhoea) complains or cries when weeing is in pain is getting sicker is not improving after 2 days has had a fever for more than 5 days.

  HealthInfo recommends the following videos

• NHS and Te Whatu Ora Waitaha – Spotting the signs of sepsis

  A video explaining how to spot the signs of sepsis, a rare but serious reaction to infection.

  Used with permission from the NHS. The video has been amended to show New Zealand emergency numbers on the screen.

  Only use the phone numbers shown on the screen, not the ones the person in the video states out loud. Those numbers will not work in Aotearoa New Zealand.

  Te Whatu Ora Waitaha extends its heartfelt gratitude to the Health Innovation Network – South London, UK, for generously granting permission to use and modify the video. This includes incorporating New Zealand emergency and Healthline phone numbers.

  HealthInfo recommends the following pages

• KidsHealth:
  • Fever in children

    What causes a fever and how to treat it.

  • Thermometers – How to use them

    Easy-to-follow instructions on the different kinds of thermometers and how to use them.

On the next page: Helping your child with fever (high temperature)

Adapted from KidsHealth as part of a National Health Content Hub collaborative. Last reviewed December 2024.

Sources

Page reference: 734318

Review key: HIFEC-49206