What is a fever?

A fever is a temperature of 38°C or higher. Fever is one of the ways the body fights infection.

It can develop slowly, over a few days, or the fever can rise very quickly. Usually, this doesn't have anything to do with the illness that causes the fever.

If your child's face feels hot to the touch and they look red or flushed, then they may have a fever. You can check their temperature with a thermometer.

A normal temperature in children is 36.5°C to 37.5°C although it depends on the person, their age, what they have been doing, the time of day and at which part of the body you take the temperature.

Body temperature is usually lowest in the early hours of the morning and highest in the late afternoon and early evening.

What causes fever in children?

Infections are by far the most common cause of fever in children. Most of these are caused by viruses, which are responsible for colds, upper respiratory infections, and the common infectious diseases of childhood. These infections don't last long and usually don't need to be treated.

Some infections are caused by bacteria and need treatment with antibiotics. These include certain ear and throat infections, urinary tract infections, pneumonia and blood infections. You need to see a doctor if you think your child has any of these infections.

There are other, relatively uncommon, causes of fever. These include allergic reactions to drugs or vaccines, chronic joint inflammation, some tumours and gastrointestinal diseases.

Fever symptoms and signs

Fever in itself is rarely harmful. But the high temperature might make your child feel uncomfortable – they might have chills or shivering when their temperature is rising, and they might sweat when it’s falling. Sometimes they might become mildly dehydrated if they're losing a lot of fluid from the fever and not replacing it.

Febrile convulsions

Febrile convulsions are seizures that happen because of a fever. They occur in about 4% of children between the ages of 6 months and 5 years. Children outgrow febrile convulsions by the age of 4 to 5 years. Febrile convulsions have no long-term consequences, but you should talk to your doctor about them.

When should you take a child with a fever to the doctor?

You don't need to see a doctor if your child is over 3 and is not too sick despite the fever.

Some symptoms that appear when a child has a raised temperature require urgent attention and you should call triple zero (000) and ask for an ambulance. These symptoms can include the child:

• being listless or not responding to your voice
• losing consciousness or having a seizure (sometimes called a 'fit') for the first time
• having difficulty breathing

You should also see or contact your doctor if your child:

• is over 6 months and shows other signs of being unwell - for example, they are floppy and drowsy or you are concerned about them
• is vomiting
• has ongoing headaches
• has ongoing tummy pain
• has a stiff neck
• the light is hurting their eyes
• the fontanelle (soft spot on your baby's head) is bulging
• is not taking fluids well
• is not passing urine well
• has had the fever for more than three days
• has travelled or been in contact with someone with a serious infection

Any baby under 3 months of age with a fever should be taken straight to the nearest emergency department.

You can check your child's symptoms using healthdirect's online Symptom Checker to get advice on when to seek medical attention.

If your doctor's surgery is closed, contact the doctor's out-of-hours service or call healthdirect on 1800 022 222.

How to treat a child with a fever

Most causes of a raised temperature in a child are usually not serious and can be managed at home. A fever will run its course regardless of treatment. Your child's temperature will return to normal when the infection or other cause of the fever has completely gone.

In babies under 12 months, fever might be a sign of a more significant illness, and you do need to seek medical advice.

Generally, children handle fever well. However, if your child has a fever, here are some ways to make them more comfortable:

• Dress them in light clothing, or even undress them to their nappy or singlet and pants.
• Cover them with a sheet if they are shivering.
• Keep the room at a comfortable temperature by adjusting the heating or opening a window.
• Give them plenty of cool, clear fluids such as water, weak tea or diluted soda water, lemonade or juice to drink. Try to get them to drink little and often. (Lemonade and juice are too strong for a child with gastroenteritis diarrhoea; they must be diluted.)
• If your child is not hungry, that's not a problem. The most important thing is to make sure they are drinking enough to avoid dehydration.

Cool baths, sponging and fans can actually make your child more uncomfortable, and shivering can increase the body temperature.

Medication

There is no need to give medicines to a child for fever unless they are in pain or discomfort.

Paracetamol can be given to children of more than 1 month for pain and symptoms of fever. Make sure you have the right strength for your child's age and weight since overdosing can be dangerous. Read and follow the directions on the label carefully. If you are not sure, check with your doctor or pharmacist.

Ibuprofen can be given for pain and symptoms of fever in children of 3 months and over who weigh more than 5kg. Avoid ibuprofen if your child has asthma, unless advised by your doctor.

Don't give aspirin to children under 16 unless it's specifically prescribed by a doctor.