What exactly is fever?

Generally, a fever is the body’s natural reaction to illness or infection. From a temperature standpoint, the health profession typically defines fever as any body temperature greater than 37.5 degrees Celsius when measured under the arm. However, temperature can vary from body part to body part and from thermometer to thermometer, depending on where you’re measuring your child’s temperature and with which type of thermometer, as different models have varying degrees of accuracy.

What is a high temperature for a child?

It helps to have a guide to normal temperature ranges by thermometer type (though always check the manufacturing information for your own individual thermometer):

Site of Measurement Normal Body Temperature
Rectal 36.32 – 37.76°C
Mouth 35.73 – 37.41°C
Under the arm (axilla) 35.01– 36.93°C
Ear 35.76 – 37.52°C


If you find your child does have a fever (when body temperature rises above normal), you might also notice they:

  • Feel hot to your touch
  • Have a faster heart rate and breathing rate
  • Look unwell
  • Are more irritable or sleepier than usual
  • Have flushed, sweaty or clammy skin
  • Are shivering

What causes fever?

A higher temperature shows that your body's immune system is fighting something and colds are one of the most common causes of fever in children – children get around six to twelve colds a year.

Some children also develop a fever after vaccination.

What’s the best way to measure their temperature?

Thermometers are the most reliable ways of measuring temperature – check your thermometer’s instructions for the best place on the body to take the reading.

How can you relieve your child’s fever?

If the fever is making your child uncomfortable, reducing it can help them feel better.

Between doses of an analgesic designed specifically for children, such as Nurofen for Children, keep offering small drinks of water or milk.

When does your child need to see a doctor?

Most fevers are the result of mild childhood illnesses and can be managed at home. However, you should see a doctor if you feel worried, or if your child is under three months and has a fever above 38°C. If your child is immunocompromised (has a weakened immune system) due to a medical condition or medical treatment and has a fever above 38°C, then you should see a doctor, even if they have no other symptoms.


For all other children, take them to see a doctor if their temperature is above 38°C and they have any of the following symptoms:

  • a stiff neck or light is hurting their eyes
  • vomiting and refusing to drink much
  • a rash
  • more sleepy than usual
  • problems with breathing
  • pain that doesn’t get better with pain relief medication.


Also take your child to a doctor if they:

  • have a fever above 40°C, but show no other symptoms
  • have had any fever for more than two days
  • seem be getting more unwell
  • have had a febrile convulsion (fit that occurs when they have a fever).

Although most of the illnesses that cause fevers last just a few days, they can be difficult days for you both. You can help your kids feel more comfortable by dressing them lightly and giving them frequent fluids and an appropriate analgesic designed specifically for children. Nurofen for Children contains ibuprofen, which relieves pain and can help reduce fever for up to eight hours. With your loving care, most children will soon be back to their normal, bubbly selves.