Fever in children

Symptoms of fever in children

Typical symptoms of fever in children are:

• A raised body temperature, measuring 38°C or higher.

• Feeling hot to touch.

• Feeling cold and shivery.

• Looking pale.

• Headache.

• Tummy ache.

• Red or flushed skin.

• Feeling sick.

The actual level of the temperature in fever is not a good guide to how severely ill a child is once they are older than 6 months.

Fever associated with common, self-limiting viral infections such as a cold typically causes a temperature that rises and falls over a total of 12-72 hours. Children often complain of feeling cold at the start of a fever. They may look pale and feel shivery, yet will feel hot and dry to the touch. Later they often say they feel hot, and will be sweaty and flushed.

How to measure a child's temperature

Forehead strip thermometers are not very accurate. Ideally you should use one of the following to measure your child's temperature:

• Under 4 weeks old, with an electronic thermometer in the armpit.

• Between 4 weeks and 5 years old:

  • With an electronic thermometer in the armpit.

  • With a chemical dot thermometer in the armpit.

  • With a digital thermometer designed to be placed in the ear.

When should you go to the doctor?

The National Institute for Health and Care Excellence (NICE) has produced guidelines aimed to help healthcare professionals assess children with fever. These can also be useful to parents.

They look at the symptoms seen in children with fever and allocate them to categories of 'green', 'amber' and 'red'. They are shown in the table below.

Green symptoms are reassuring. They mean that your child's symptoms suggest they are at low risk of serious illness.

Amber symptoms suggest that you need a doctor's advice. They suggest that your child might be at slightly increased risk of more serious illness.

Red symptoms suggest that you need urgent medical advice. They suggest that your child's symptoms could indicate a serious illness, needing emergency help.

Not all possible symptoms are included in the guidance - for instance, tummy (abdominal) pain is not mentioned and, unless it is mild, it usually does need assessing by a doctor.

Some of the guidance concerns the kind of symptoms which a trained healthcare professional is expected to assess but which you may feel uncomfortable trying to measure, such as number of breaths per minute (respiratory rate) and heart rate (which usually needs a stethoscope for accurate assessment in a small child).

They are included here for completeness: if ANY red or amber signs are present you should seek medical help; you do not need all of them to be present in order to do so.

Green/amber/red symptoms in fever in children aged below 5 years

Most fevers in children over 6 months of age are not serious and are a very common occurrence with coughs, colds and all the other common childhood illnesses. However, fever is also seen in more serious illnesses and the red or amber signs above can help to differentiate between these.

Fever in children aged 3-6 months is less common and it is important to seek medical advice if the temperature is 39°C or more.

Fever in a baby aged less than 3 months is unusual and worrying. You should seek medical advice if the temperature is 38°C or more; the GP is often an appropriate place to start, but if there is a true fever in a child aged less than 3 months, you will probably also be referred to a paediatrician on the same day.

Causes of fever in children

The most common causes of fever in children in the UK are viral infections. There are many other uncommon causes. Some of these will show other obvious signs.

• Infections with viruses are the most common cause. Viral infections cause many common illnesses such as colds, coughs, flu, diarrhoea, etc. Sometimes viral infections can cause more serious illnesses. Viruses are also the most common causes of sore throat, ear infections etc.

• Infections with bacteria are much less common than viral infections but also cause fevers. Bacteria are more likely to cause serious illness such as pneumonia, joint infections (septic arthritis), urine infections, kidney infections, septicaemia and meningitis. However, bacteria can also cause fever in less serious infections such as ear infections and infected skin rashes.

• Inflammatory conditions and reactions may cause fever, including Kawasaki disease, some types of arthritis, and reactions to some medicines.

• Immunisations: sometimes children develop a fever after an immunisation. This is because immunisations are generally designed to 'trick' the body's immune system into thinking it sees an infection, so that it develops immunity. Fevers following immunisation are not usually high or prolonged.

• Other types of infection: these include 'tropical' infections such as malaria and dengue, and conditions which are more common outside the UK, such as tuberculosis.

• Heat stroke is a possible cause of raised body temperature, although technically this isn't a fever, as the body is being heated from the outside (whereas in fever the body does the heating itself).

Why do children get fevers?

Fever is a part of the body's natural defences against infection. Fever is created by the immune system under the direction of a part of the brain called the hypothalamus. The hypothalamus acts like a central heating thermostat. Fever happens when the hypothalamus sets the body temperature above its normal level.

It does this in response to an infection because it detects the presence of infectious agents like bacteria or viruses. It is believed that the increased temperature is a protection the body has developed to help fight the germs that cause infections, as they tend to multiply best at normal body temperature.

How common is fever in children?

Fever and feverish illness are very common in young children, particularly in those aged less than 5 years. Three to four out of every 10 parents of children aged less than 5 years say their child has had a fever in the past year.

It is one of the most common reasons for a child being taken to the doctor. Fever is also the second most common reason for a child being admitted to hospital and it can be a cause of great anxiety in parents.

How is the cause of fever in children diagnosed?

The healthcare professional will try to work out why your child has a fever. This will usually include asking about your child's health and symptoms.

Your child may need to be examined (a 'face-to-face' consultation). In this case it is most likely that your child's temperature, pulse and breathing will be checked. Your child will be checked for lack of fluid in the body (dehydration) and their blood pressure may be taken.

A urine sample may be tested. Rarely, an ambulance may be called. This does not necessarily mean your child is very ill, only that they need to be assessed quickly in hospital.

Are further tests needed?

Usually the healthcare professional who assesses your child will decide that no further tests are necessary. This is usually because there are no worrying signs in your child's condition and your doctor or nurse feels able to diagnose the infection, based on their training and experience.

Occasionally, however, they are uncertain.

• This may be because your child has some of the 'amber' or 'red' warning signs.

• It may be because a specific, worrying infection such as meningitis is in the community, and your doctor thinks that your child could be affected, or because they have symptoms of meningitis such as a stiff neck.

• It may be because your doctor or nurse feels unsure about the diagnosis and thinks that a second opinion and further tests are needed.

If this is the case you may be asked to go to the paediatric ward or Accident and Emergency department. If your child is very unwell an ambulance will be called. However, if that is not the case, and you are able, you may be asked to make your way there by car; in some cases this will be quicker than waiting for an ambulance.

On the ward your child is likely to have several tests done. These will vary, depending on how your child appears and on what the doctors find when they assess and examine your child.

They may include:

• Blood tests.

• Urine tests.

• Swabs.

• Sputum samples.

• X-rays.

• Ultrasound scan.

• Lumbar puncture.

You may be discharged home from the hospital after this or, if doctors are still not certain that your child is at very low risk of a more serious condition, your child may be kept for observation or treatment.

What to do if a child has a fever/high temperature?

A child with a fever may look flushed and irritable and they may not feel like doing very much.

To help your child you should:

• Make your child comfortable - details below.

• Check for signs of lack of fluid in the body (dehydration).

• Check for signs of serious infection.

• Keep your child off school or nursery until they are better.

You do not need to use paracetamol and ibuprofen if your child is comfortable and not distressed by the fever, aches or pains. Because fever is of benefit in getting rid of the underlying infection more quickly, if your child is not distressed by the fever, it is best to let it continue.

In most bouts of fever that are not caused by serious illness, the temperature generally comes down quickly. It is not unusual to see a child playing happily as soon as their temperature has come down. It is reassuring if a child improves as their temperature drops.

A child with a serious infection usually gets worse despite efforts to bring their temperature down. In addition, they may have other worrying symptoms - for example, breathing problems, drowsiness, convulsions, pains, or headaches which become worse.

See the separate article called Fever treatment for children: a doctor's advice.

How to manage a fever

The important things are to try to keep your child calm, reassured and comfortable.

• Give plenty to drink. This helps to prevent a lack of fluid in the body (dehydration). You might find that a child is more willing to have a drink if they are not so irritable. So, if they are not keen to drink, it may help to give some paracetamol first.

• Cooling an over-warm room may be helpful.

• Tepid sponging is not recommended for treatment of fever. This is because the blood vessels under the skin become narrower (constrict) if the water is too cold. This reduces heat loss and can trap heat in deeper parts of the body. The child may then get worse. Many children also find cold-sponging uncomfortable.

• Cold fans are not recommended, for the same reasons, although cooling an over-warm room with adequate ventilation is sensible.

• Children with fever should not be underdressed or over-wrapped.

Medicines like paracetamol and ibuprofen should not be used for fever unless your child appears distressed. If they are not distressed it is better to let the fever do its job and run its course.

When using paracetamol or ibuprofen in children with fever

• Continue for as long as the child appears distressed.

• Consider changing to the other medicine if the child's distress is not relieved by the first.

• Only consider alternating these two medicines if the distress persists or comes back before the next dose is due.

• Do not give both at the same time.

• Ibuprofen should not be used if your child is dehydrated because studies have shown that this can increase the risk of kidney failure.

• Using paracetamol and ibuprofen does not prevent febrile convulsions and should not be used for this purpose alone.

• Ibuprofen should also not be used if your child has chickenpox.

You can buy paracetamol and ibuprofen in liquid form, or melt-in-the-mouth tablets, for children. The dose for each age is given with the medicine packet.

Remember: paracetamol and ibuprofen do not treat the cause of the fever - they merely help to ease discomfort. They also ease headaches and aches and pains. You do not need to use these medicines if your child is comfortable and not distressed by the fever, aches or pains.

When does a fever indicate serious illness?

All the symptoms associated with harmless viral fevers can also occur in more serious illness. It can be difficult to determine whether or not your child's fever symptoms should worry you.

There are some features of a fever which will help you assess whether you need to seek medical advice.

These include that your child:

• Has normal-coloured skin, lips or tongue.

• Responds to you normally.

• Is basically content and will smile.

• Stays awake or awakens quickly and easily when you wake them.

• Has a strong normal cry, or is not crying.

• Has moist lips and tongue.

Features of a fever that suggest your child may be more unwell

• Your child is aged 3-6 months and has a temperature of over 39°C.

• Pale skin, lips or tongue.

• Not responding normally to you.

• Not smiling.

• Wakes only with prolonged effort by you.

• Not wanting to do anything; inactive.

• Dry mouth and lips.

• Poor feeding in babies.

• Reduced wet nappies in babies.

• Attacks of shivering.

• Has had a fever for five days or more.

• Has swelling of a limb or joint.

• Isn't using an arm or leg or isn't able to put any weight on one leg.

Features of a fever that suggest your child is seriously unwell

• Your child is less than 3 months of age and has a temperature of over 38°C.

• Pale/mottled/ashen/blue skin, lips or tongue.

• No response to you.

• Does not wake, or if you wake them, does not stay awake.

• Weak, high-pitched or continuous cry.

• Grunting noises when breathing.

• Indrawing of the muscles between the ribs when breathing (this is particularly true in babies).

• Reduced skin turgor (when you very gently pinch the skin on the back of the hand between your fingers, it does not bounce back but keeps the pinched shape).

• Bulging fontanelle (the 'soft spot' on the top of the head of babies up to about 18 months of age).

• Sunken fontanelle - suggests lack of fluid in the body (dehydration).

• A rash that doesn't fade when you press a glass against it.

• Neck stiffness.

• Seizures.

• A bulging fontanelle (the soft spot on the top of a baby's head).

Features that suggest your child is dehydrated

Dehydration can develop quickly in a child who is feeling sick, being sick (vomiting) or has diarrhoea. Once dehydration sets in, nausea and vomiting can get worse, which can be a vicious cycle that is hard to break.

Signs of dehydration include:

• Dry mouth or tongue.

• No tears when crying.

• Sunken appearance to eyes.

• Drowsiness.

• Cool hands and feet.

• Generally becoming more unwell.

• Reduced skin elasticity, or turgor (when you very gently pinch the skin on the back of the hand between your fingers, it does not bounce back but keeps the pinched shape).

• Babies stop passing urine (although this can be difficult to detect if they also have diarrhoea), and the soft spot (on the top of the head) may become sunken in. Small babies can become dehydrated very quickly.

Seek medical advice if you suspect that your child is becoming dehydrated.

Febrile convulsions

Some children have a tendency to febrile convulsions. This is a type of seizure triggered by a rapid rise in body temperature. Some children have only one febrile convulsion, ever, but others go on to have them more often. See the separate leaflet called Febrile seizure (Febrile convulsion).

Febrile convulsions, and seizures due to infections such as meningitis, can look very similar. If a child has a seizure for the first time, it is important to rule out serious conditions such as meningitis before deciding it is a febrile convulsion.

Meningitis and septicaemia

Two of the most serious infections are meningitis and blood infection (septicaemia). These are uncommon; the vast majority of children with a fever do not have these infections.

The symptoms often develop quickly, over a few hours or so, or more slowly, over a few days. The symptoms may suggest a less serious illness at first, such as flu. But, even if you think it was flu to start with, if symptoms become worse and your child seems really unwell you should seek urgent medical advice.

Meningitis and septicaemia are always medical emergencies, so it is essential to know what signs to look out for. See the separate leaflets called Meningitis symptoms checklist and Child sepsis safety net for more details.

Dr Mary Lowth is an author or the original author of this leaflet.