Fever in children

Expert reviewer, Dr Adrian Raby, General Practitioner
Next review due July 2020

Normal body temperature varies from child to child and goes up and down naturally throughout the day. But, if your child’s temperature is 38°C (100.4°F) or above, then it means they have a fever.

Fever is very common, especially in young children. In fact, by the time your child reaches 18 months, they’re likely to have had around eight different infections with a fever. When your child is ill and has a fever, it can be upsetting and worrying, but there are things you can do to help your child feel better.

A fever is usually caused by an infection of some kind, and often gets better on its own. But, it can sometimes be a sign of a more serious health problem. So, it’s important to know how to manage and treat your child’s fever, and when to get medical help.

A little girl asleep on her mum's shoulder

Symptoms of fever in children

If your child has a fever, they will have a body temperature of 38°C or above. They may feel or look generally unwell. Your child may not be as active and engaged, and they may not want to eat or drink.

Sometimes minor illnesses can cause a very high temperature, whereas some serious infections can cause only a small rise in temperature. As well as your child’s high temperature, you may notice other symptoms of infection, such as:

  • diarrhoea and vomiting
  • earache, or clutching at their ears
  • cough, runny nose or wheezy breathing
  • a rash

Getting medical advice or help

You should get medical help straightaway by taking your child to accident and emergency, or calling an ambulance, if they:

  • are less than three months old and have a temperature of 38°C or above
  • are unusually sleepy or difficult to wake up
  • have bluish, pale or mottled skin
  • have a weak, high-pitched cry or won’t stop crying
  • are grunting, having difficulty breathing or are breathing very quickly
  • have a stiff neck
  • dislike bright lights
  • develop a rash that doesn’t disappear when pressed
  • have a bulging fontanelle (the soft spot on the top of the head of babies)
  • they don’t respond to you in the usual way, for example, your baby doesn’t smile when you smile
  • they have swollen joints, arms or legs

You should seek urgent medical advice from your GP or out-of-hours service if:

  • you think they’re getting worse instead of better
  • there are signs that they may be dehydrated, such as producing small amounts of dark urine (see our FAQ below for more information)
  • they are shivering and sweating
  • they are less active than usual
  • they are three to six months old and have a temperature of 39°C or above
  • their fever has lasted for five days or more
  • they can’t place their weight on one or both legs, or they don’t seem to be using their arms or legs

In some children, a high fever can lead to fits called febrile seizures or convulsions. If this happens, your child can become unconscious and twitch and shake for several minutes. You can find out more about febrile seizures, and what to do if your child has one, in the FAQ section below.

Diagnosis of fever in children

You can see whether your child has a fever by checking their temperature using a thermometer. You can do this yourself at home.

If your child is less than four weeks, use an electronic thermometer to take their temperature under their arm (in their armpit). For children aged one month to five years, you can measure temperature under the arm or in the ear using an electronic thermometer. You can use a digital mouth thermometer for children aged over five. Follow the instructions that come with the thermometer, to make sure you get an accurate reading.

Mercury thermometers aren’t used anymore because of the risk that they could break and harm your child. Thermometers that measure temperature on your child’s forehead can be unreliable, so are best not used.

At the doctor’s

Your GP will ask about your child's symptoms and medical history and examine them. If you have travelled abroad recently, or had contact with anyone who has, you should let your GP know.

They will take your child’s temperature and check their heart rate. Your GP might check for other signs of infection, by examining your child’s ears, throat and abdomen and listening to their breathing.

There may be an obvious cause for your child’s fever, so they may not need to have further tests. If the cause of your child’s fever isn’t clear, your GP may ask for a urine sample. Your GP may also refer your child to a paediatrician (a doctor who specialises in children’s health) for more tests.

Treatment of fever in children

Fever is often caused by a viral infection and will get better on its own. So, treating your child’s fever may mean doing nothing except keeping them comfortable, and waiting for them to get better.

However, for some children a fever can be the sign of a more serious illness, so it’s important to keep an eye out for any changes in behaviour and any other symptoms.


Fever is part of the body’s natural response to infection, so sometimes it doesn’t need to be treated, as long as your child isn’t distressed. Treating fever with medicines doesn’t prevent febrile seizures, as people used to believe.

You can offer your child regular drinks to help them stay hydrated and to prevent dehydration. If you’re breastfeeding then you can carry on doing this as normal. You can find out more about dehydration in the FAQ section below.

Although it’s important that your child doesn’t overheat, take care to ensure that they aren’t underdressed either. Don’t actively try to cool your child, for example with tepid sponging or a cool bath. It’s unlikely to work; it can be distressing for your child and it can cause them to start shivering.

While your child has a fever, keep them away from school or nursery.


If your child has a fever, and they’re also uncomfortable or distressed, you can give them paracetamol or ibuprofen. You shouldn’t give these medicines just to bring down their temperature if your child is otherwise well.

If you try paracetamol and it doesn’t seem to work, then you can try ibuprofen instead and vice versa. Don’t give both medicines at once though.

Make sure you keep a note of how much paracetamol or ibuprofen your child has had, and when you’ve given it. This will help to make sure you don’t accidentally give them more than the recommended amount.

You can buy medicines that are suitable for children from a pharmacy without a prescription. Always read the patient information leaflet that comes with your child’s medicine and if you have any questions, ask your pharmacist for advice.

If your child has a bacterial infection, your GP may prescribe a course of antibiotics, although the infection will usually go away without the need for any medicines.

Causes of fever in children

There are many conditions that can cause a fever in children. Most fevers in children are caused by viral and bacterial infections. These can include coughs, colds, flu and other viruses, and throat, ear, chest and urine infections. Rarely, a fever can be a sign of a serious illness, such as meningitis or septicaemia.

More rarely, children can also develop a fever as a symptom of conditions other than an infection. For example, some autoimmune conditions like Still’s disease, some cancers, liver and kidney disease may all cause a fever.

Fever can also be a side-effect of some immunisations. See our FAQs for more information.

Frequently asked questions

  • You become dehydrated when there isn't enough water in your body and children are more likely to get dehydrated than adults. Your child can lose a lot of fluid if they have a fever, so it's important to check for signs of dehydration.

    When your child or baby is beginning to get dehydrated they may:

    • seem generally unwell
    • be irritable and/or lethargic
    • pass less urine
    • have sunken eyes and a dry mouth
    • have sunken fontanelles – the soft spots on the top and back of their head

    Give your child regular drinks if he or she has a fever. If you’re breastfeeding, try to continue feeding your baby. Contact your GP for advice if you’re concerned that your child may be dehydrated.

  • Yes, immunisation can sometimes cause fever. Some immunisations, such as tetanus, can cause a fever within a few hours. Others, such as MMR, may lead to fever a few days or a week later.

    It’s common to have a mild fever after an immunisation. When your child has the injection, ask what you should to do if a fever develops. You can give your child paracetamol or ibuprofen to treat any discomfort or fever, but in most cases, it’s best not to give these to prevent a fever. This is because giving paracetamol or ibuprofen may affect how well the immunisations work. An exception is the meningitis B immunisation for children under the age of one. If your child has this immunisation, you’ll be given information about giving them liquid paracetamol to reduce the chances of fever.

  • Febrile seizures can happen in children under the age of five. They’re caused by a very high temperature. Although they can be frightening, they aren’t usually harmful. Stay with your child throughout the seizure to keep them safe and get medical advice once the seizure is over.

    More information

    Febrile seizures or convulsions are fits caused by a high temperature. They happen in younger children, usually between the ages of six months and five years. A seizure can be triggered if your child’s temperature becomes very high, regardless of whether that happens quickly or slowly.

    During a febrile seizure, part or all of your child's body shakes or twitches. Your child could also become unconsciousness during the seizure.

    Although febrile seizures rarely last longer than a few minutes, they can be very frightening. If your child has a febrile seizure, try to stay calm. Don’t restrain your child, but try to make them as safe as possible, using your hands or a cushion to protect their head. If they’re in a place where they may get hurt, move them to somewhere safe if you can. Don’t put anything in their mouth.

    Febrile seizures usually last just a few minutes and stop without needing any treatment. If the seizure lasts for longer than five minutes, you should call for an ambulance. If the seizure lasts for less than five minutes, you should still contact your GP or out-of-hours service as soon as possible to rule out a serious illness.

    When the seizure is over, make sure your child is breathing properly and put them on their side in the recovery position until they fully wake up. After a seizure, your child may be sleepy for up to an hour.

    Around one in three children who have a febrile seizure will go on to have another. Although febrile seizures can be frightening, most children recover well with no lasting health problems.

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Related information

    • Fever in infants and children. The MSD Manuals., last full review/revision August 2016
    • Fever in under 5s: assessment and initial management. National Institute for Health and Care Excellence (NICE)., May 2013
    • Ill and feverish child. PatientPlus., last checked June 2013
    • Meningitis. PatientPlus., last checked June 2013
    • Non-contact infrared thermometers. NIHR Diagnostic Evidence Cooperative Oxford., published November 2013
    • Feverish children. NICE Clinical Knowledge Summaries., last revised September 2013
    • health. Oxford handbook of general practice (online). Oxford Medicine Online., published April 2014
    • Assessment of fever of unknown origin in children. BMJ Best Practice., last updated August 2016
    • Green book. Public Health England., published August 2012
    • Protocol: Supply or administration of paracetamol oral suspension 120mg/5mL to infants under 12 months of age receiving primary doses of MenB vaccination. Public Health England., last updated September 2015
    • Dehydration in children. PatientPlus., last checked April 2014
    • Diarrhoea and vomiting caused by gastroenteritis in under 5s. National Institute for Health and Care Excellence (NICE)., published April 2009
    • Febrile seizure. BMJ Best Practice., last updated November 2016
    • Febrile seizures. NICE Clinical Knowledge Summaries., last revised October 2013
    • Febrile convulsions. PatientPlus., last checked June 2015
  • Reviewed by Graham Pembrey, Lead Editor, July 2017
    Expert reviewer, Dr Adrian Raby, General Practitioner
    Next review due July 2020

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