A fever is when your child’s body temperature is higher than 38°C. A normal temperature range for children is 36.5°C-38°C.
Fever is not an illness in itself – it’s usually the body’s immune system responding to an infection, disease or inflammation.
Fever in itself is rarely harmful. Generally, children handle fever well.
Causes of fever and high temperature
Children get fevers for many reasons.
Infections are the most common cause of fever in children. In general, fever is a sign your child’s body is fighting an infection.
Most childhood infections are caused by viruses. Other infections might be caused by bacteria. Infections that might cause fever include:
- common colds, influenza and other upper respiratory tract infections
- diseases like chickenpox, measles and mumps
- ear and throat infections like middle ear infection and tonsillitis
- urinary tract infections in babies and toddlers and urinary tract infections in children and teenagers
There are other less common causes of fever. These include allergic reactions to medicines or vaccines, chronic joint inflammation, some tumours, and gastrointestinal diseases like inflammatory bowel disease.
A fever or high temperature might come on slowly and rise over a few days, or it might rise very quickly. It might also rise and fall throughout the day.
A high temperature might make your child feel uncomfortable. Your child might have chills or shiver when their temperature is rising, and they might sweat when it’s falling. Sometimes your child might become mildly dehydrated if they’re losing a lot of fluid from the fever and not drinking enough.
Sometimes children between the ages of 6 months and 6 years have a febrile seizure, but this is rare.
Most fevers and the illnesses that cause them last only a few days. But sometimes a fever will last much longer, particularly if it’s the sign of an underlying illness or chronic disease.
If you think your child has a fever, taking your child’s temperature with a thermometer will tell you whether your child’s temperature is higher than normal.
Medical help: when to get it for fever
If your child aged 0-1 month has a fever, taken them to a hospital emergency department as soon as possible.
If your child aged 1-12 months has a fever, take them to a GP as soon as possible.
If your child aged over 12 months has a fever, take them to a GP if their fever lasts more than 4 days or if you’re worried for any other reason. You should also see a GP if your child:
- looks sicker than before – for example, your child is more pale, lethargic and weak
- has trouble breathing
- is drowsy
- seems mildly dehydrated, refuses to drink or is weeing less often
- has a stiff neck or a mild headache or light hurts their eyes
- vomits or has diarrhoea
- has mild pain or discomfort.
If any of these symptoms are severe or your child’s condition worsens rapidly, go to a hospital emergency department or call an ambulance by phoning 000. If your child finds it very difficult to breathe or is unresponsive, call 000 straight away.
If your child has a fever, make sure your child is drinking enough to avoid dehydration:
- If your breastfed child is younger than 6 months, offer extra breastfeeds.
- If your formula-fed child is younger than 6 months, offer smaller amounts of formula more often.
- If your child is older than 6 months, keep breastfeeding or bottle-feeding. You can also offer your child clear fluids like water or use an oral rehydration fluid like Gastrolyte or Hydralyte. You can buy these from pharmacies and many supermarkets.
You might need to give your child smaller amounts of fluid, but more often.
You can treat fever with paracetamol if the fever is making your child hot and uncomfortable. Check the medicine packaging for the recommended dose and frequency. You can use ibuprofen if your child is older than 3 months.
If you need to use medicine to treat a fever for longer than 48 hours, see a GP.
Here are other things you can do to make sure your child is comfortable:
- Dress your child in light clothing. One layer less than your child usually wears is about right.
- Avoid cool baths, sponging and fans. These can make your child more uncomfortable.
- Don’t pressure your child to eat. If your child isn’t hungry during a fever, that’s OK.
If your child’s fever is caused by a bacterial infection, your child might need treatment with antibiotics to get rid of the infection.
Don’t give your child aspirin for any reason unless it’s prescribed by a doctor. Aspirin can make your child susceptible to Reye’s syndrome, a rare but potentially fatal illness. It can also cause serious illness or even death in children with chickenpox or flu symptoms.