What is a fever?
A normal temperature range for children is 36.5°C-38°C. A fever is when your child’s body temperature is higher than 38°C.
Fever is not an illness in itself, but is the sign of an illness.
Causes of fever and high temperature in children
Children get fevers for all kinds of reasons.
Infections are by far 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
There are other less common causes of fever. These include allergic reactions to drugs or vaccines, chronic joint inflammation, some tumours and gastrointestinal diseases like Crohn’s 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. These things usually don’t have anything to do with the illness that causes the fever.
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.
Children between the ages of six months and six years might have a febrile convulsion.
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.
When to see your doctor about fever and high temperature
Babies under three months with a fever should be taken to a hospital emergency department straight away. This is because it’s harder to tell whether they have a serious underlying illness.
In children aged 3-12 months, fever might be a sign of a more significant illness, so seek medical advice from your GP within the same day.
In children over 12 months, go to a hospital emergency department or call an ambulance straight away if your child has a fever and also:
- looks sicker than before – for example, your child is more pale, lethargic and weak
- has trouble breathing
- becomes drowsy or unresponsive
- seems dehydrated, refuses to drink or is weeing less often
- complains of a stiff neck, persistent headache or light hurting their eyes
- vomits persistently, or has frequent bouts of diarrhoea
- doesn’t improve in 48 hours
- suffers pain or is continuously crying
- is causing you to worry for any other reason.
You know your child best, so trust your instincts if your child doesn’t seem well or is showing signs of a serious illness that requires urgent medical attention.
Fever in itself is rarely harmful. Generally, children handle fever well.
You should treat a fever only if it’s making your child uncomfortable. A fever will run its course regardless of treatment.
If your child has a fever, the most important thing is to make sure your child is drinking enough to avoid dehydration:
- If your breastfed child is younger than six months, offer extra breastfeeds.
- If your formula-fed child is younger than six months, offer the usual amount of formula.
- If your baby is older than six months, keep breastfeeding or bottle-feeding. You can also offer your child clear fluids like water.
- If your child is older, 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.
Here are some other things you can do to make sure your child is comfortable:
- Dress your child in light clothing.
- Give your child paracetamol in the recommended dose and frequency. You can also give ibuprofen to children aged over three months. Don’t give fever-lowering medication too often or for too long, because it can cause side effects like liver damage.
- Avoid cool baths, sponging and fans. These can actually 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.
Do not give your child aspirin for any reason. 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.