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Children’s health: Fever or high temperature

Children’s health: Fever or high temperature

If you’re a parent of a young child, one of the things you may worry about – at least where their health is concerned – is when they have a fever (pyrexia).
Fever, says the NHS, is a temperature of 38C or higher. A normal temperature in babies and children is about 36.4C, though this can vary a little from one child to the next (i).
When a young child has a fever, it often means they may have an underlying infection – though fever has other causes too. But fever is also very common in young children, with the latest figures suggesting each year between 20 - 40 per cent of parents in the UK see a healthcare professional because their child has a high temperature (ii).
The good news is that most fevers in children aged six months or older aren’t harmful. But if your child is younger than six months, there’s a bigger chance their fever could be more serious:

  • If your child is aged between three to six months, get medical advice as soon as possible if their temperature is 39C or higher.

  • If your child is younger than three months old, speak to a healthcare professional promptly if they have a temperature of 38C or higher.


What is a fever in children?      

The most obvious sign that your child has a high temperature is that they feel hotter than usual when you touch their back or chest (though be aware that some things can easily make a child’s temperature rise slightly, such as hot baths, wearing excessively warm clothes and exercising). Confusingly, children can often say they feel cold at the start of a fever, and even though they feel hot and dry when you touch them they may actually look pale and shivery – though later on they may look flushed and say they feel hot.
A child may also have a headache or stomach ache at the same time as having a fever, with other possible symptoms including:

  • Feeling tired and listless

  • Not sleeping well

  • Feeling sick

  • Lack of appetite

  • Swollen glands in the neck and under the arms

  • Dribbling (which may be a sign of a sore throat)

  • Watery eyes

Read on for more details of the symptoms of fever and what you should do if your child has one (see When should you see a doctor? below).
Fever doesn’t sound like much fun, especially for children, but it is a natural part of the way the body fights infection. When your body is invaded by potentially harmful bacteria or viruses your immune system responds in a number of ways, one of which is to produce chemicals called pyrogens.
These chemicals are thought to act on the part of the brain that regulates body temperature called the hypothalamus, and they ‘trick’ the hypothalamus into thinking the body is actually cooler than it is. As a result the hypothalamus raises the body’s temperature by reducing heat loss, which is thought to activate the immune system’s white blood cells as well as increase the production of antibodies (read our article on how your immune system works to find out more).
Reducing heat loss also makes you sweat less and shiver, while the blood vessels in your skin shrink to try and stop heat loss, making you look pale. This explains why you or your child feel cold even when your temperature is rising. Meanwhile a fever may have a direct impact on bacteria and viruses that multiply best at normal body temperature. It may also even kill some types of bacteria and viruses that cannot tolerate higher temperatures.

How to check your child for fever

The best way to find out if your child has a fever is to measure their temperature with a thermometer. The NHS recommends using a digital thermometer, which you can buy from pharmacies and supermarkets (i). Here’s how to do it:

  • Put the thermometer inside the top of your child’s armpit.

  • Close their arm over the thermometer and keep it pressed to the side of the body.

  • Check the instructions that came with your thermometer to find out how long you should leave it in place, or wait for the beep if you have a thermometer that has an audible alert when it’s ready.

  • Take the thermometer out and check the display.

Try to avoid taking your child’s temperature straight after they’ve had a bath or if they’ve been wrapped in a blanket or wearing lots of warm clothes. Meanwhile avoid using forehead strip thermometers, as experts claim they aren’t very accurate (iii). You could, however, use a digital thermometer that you place in your child’s ear if they are older than four weeks.
It’s also worth remembering that the actual level of the temperature doesn’t always indicate how ill a child is if they’re six months of age or older. That’s because some minor illnesses can cause a high fever, while some more serious illnesses often only cause a mild fever. Indeed, other symptoms that accompany fever tend to be better signs of the severity of the illness than the fever itself (for more about this, see below). The exception is when a child’s temperature reaches 41C or higher, which itself can be dangerous – though such a high temperature is rare.

What causes fever in children?

Infections caused by viruses are the most common causes of fever in children here in the UK (iii). These include viruses that cause common conditions such as coughs, colds, flu and gastroenteritis (tummy bugs). 
Bacterial infections cause fevers too, though they’re less common than viral infections. Bacteria cause conditions such as ear infections, (infected rashes, for instance), sinus infections and urinary tract infections, skin infections as well as pneumonia, kidney infections and other more serious illnesses such as septicaemia and meningitis.
Other less common causes of fever in children include:

  • Kawasaki disease (a condition that mainly affects children under the age of five)

  • Cellulitis (bacterial infection of the skin)

  • Septic arthritis (bacterial infection of the joints)

  • Encephalitis (inflammation of the tissues of the brain)

  • Heatstroke (while this can cause very high body temperatures it isn’t technically the same as a fever as the body is heated from the outside rather than the inside)

  • Tropical infections such as malaria

  • Infections that are uncommon in the UK but found elsewhere, such as tuberculosis

Vaccinations can cause fever in children sometimes too, though in this case body temperature isn’t usually high and the fever doesn’t last for long. The tetanus vaccination, for instance, can cause fever within a few hours, while the MMR vaccine may cause fever up to 10 days later. Always speak to the healthcare professional giving your child a vaccine about what you should do if your child develops a high temperature, as sometimes you shouldn’t treat a fever after a vaccine as it can affect how well the vaccine works.
What’s causing your child’s fever can also depend on how long their high temperature has lasted. Most fevers, for instance, are classed as acute, as they last for 14 days or less. These are usually caused by an infection. Chronic fevers, on the other hand, last longer, and are most often caused by a prolonged viral illness or having several infections one after the other. These infections include pneumonia, hepatitis and sinusitis, though chronic fever isn’t always caused by infections: conditions such as inflammatory bowel disease and juvenile idiopathic arthritis, for instance, can cause chronic fever too.

When should you call a doctor about a fever?

Most fevers in children aged six months or older aren’t serious. But it can be hard for parents to decide when they should care for their little one by themselves at home, and when they should seek advice from a medical professional. That’s because all the symptoms that can appear with harmless fevers can also be signs of more serious illnesses.
However the National Institute for Health and Care Excellence has produced guidelines to help healthcare professionals assess fever in children – these may also be useful for parents (iv). The guidelines follow a traffic light system, where green represents low risk, amber intermediate risk and red high risk:


If your child’s symptoms fall into this category, it means they have a low risk of serious illness and should usually be cared for at home. Symptoms in the green category include:
Skin colour: normal
Activity: responds to you normally. Smiles, appears content, Stays awake or wakes up quickly. Cries normally.
Breathing: normal.
Circulation and hydration: normal skin and eyes. Moist tongue and lips.
Other: has none of the amber or red symptoms


If your child has any of the symptoms in the amber category, you should get advice from a doctor as they may have a slightly increased risk of more serious illness (ring your GP’s surgery or call NHS 111).
Skin colour: pale
Activity: not responding to you normally. Not smiling. Only wakes up when you stimulate them for a longer-than-usual time. Less active than usual.
Breathing: faster than usual (more than 40 breaths per minute if your child is a year old or older, and more than 50 breaths a minute if they’re between six and 12 months old). Flaring of the nostrils during breathing.
Circulation and hydration: dry tongue and lips. Poor feeding (babies). Reduced urination (dry nappies, for instance). Fast heart rate (this can be difficult for parents to work out, especially as heart rates in children can vary according to their age).
Other: a temperature of 39C or higher in babies aged three to six months. Fever lasting for five days or longer. Repeated episodes of shivering alternating with sweating, which indicates body temperature persistently rising and falling (rigors). Swollen limbs or joints. Not being able to use an arm or leg.


Children who have symptoms in this category should be seen by a doctor immediately, as they may have a serious illness that requires emergency help (call 999 for an ambulance or go to your nearest hospital A&E).
Skin colour: pale, mottled, ashen or blue.
Activity: Not responding to you at all. Doesn’t wake up or, if you can wake them, doesn’t stay awake. Abnormal crying (sounds weak, high-pitched or continuous).
Breathing: fast breathing rate (more than 60 breaths a minute). Grunting. Chest draws in between or under the ribs when they’re inhaling.
Circulation and hydration: reduced skin elasticity (when you pinch the skin it doesn’t spring back into place straight away – this can be a sign of dehydration).
Other: a temperature of 39C or higher in babies up to three months old. A rash that doesn’t disappear when you press the side of a glass into it (see our article on meningitis and septicaemia in children for more information about the glass test). Stiff neck. Fits or seizures including those that last longer than five minutes (or having more than one seizure within a five-minute period). A soft spot (fontanelle) on a baby’s head that looks bigger than usual or swollen (this can make a baby’s head look as if it’s changed shape or is bigger than usual).

What is a febrile seizure?

Some children have a tendency for febrile seizures (or febrile convulsions). These are triggered when their body temperature starts to rise, and they’re more common in children between six months and five years old (v). Some children may only ever have one febrile seizure, while others continue having them more often when they have a fever. The good news is most febrile seizures don’t last very long, but they can nevertheless be very frightening.
If your child has a febrile seizure, part or all of their body may shake or twitch, and they may even lose consciousness. To help them, try to lay them in the recovery position (on their side with their head slightly tilted back) until they wake up and make sure they’re breathing properly. If the seizure lasts more than five minutes or if it’s their first seizure, call an ambulance. You should also call an ambulance if they have difficulty breathing, if another seizure starts straight after the first one stops, or if they don’t improve quickly after a short seizure.
If the seizure isn’t their first and it stops after a few minutes, you shouldn’t usually need any emergency help. However your child may need treatment for whatever’s causing the fever.

How to treat fever in children? Ways to make your child feel better

If your child has no amber or red warning signs but they do have symptoms such as sneezing, a sore throat or a runny nose, they may well have a simple viral infection such as a cold and their temperature should return to normal fairly quickly. However even if your child has no amber or red warning signals but you’re still worried, call your GP or NHS 111 to get the advice or reassurance you need.
Simple viral infections can be managed at home. Just keep checking for any symptoms that suggest a child has a more serious infection, and keep them off school or nursery until they are better (always notify their school about their illness).
There are several things you can do to help them recover and make them feel more comfortable, including:

  • Give them plenty of drinks to prevent dehydration. Also check for signs of dehydration, such as lack of urination, dry mouth and sunken eyes. If they are distressed or irritable and they refuse to drink anything, try giving them some children’s paracetamol then offer them another drink about half an hour later.

  • Try to make sure they are dressed normally for the room temperature – underdressing and overdressing can make them cool down too much or overheat.

  • Check on them regularly, including throughout the night.

  • If they’re in a hot room, try reducing the temperature a little if possible by using a fan or similar. However, if the room temperature is normal, don’t make it any cooler, as it can make fever worse. This is because overcooling can make the blood vessels just under the skin become too narrow, which can trap heat in deeper parts of the body.

  • Don’t try to cool your child by sponging them down with cool water either – this too can make their fever worse for the same reasons as above.

Also avoid giving a child with a fever medicines such as paracetamol or ibuprofen unless they seem to be distressed. This is because experts believe a fever should be allowed to run its course, as it’s a natural function of the immune system in response to infection. However if you think it’s necessary, you can give paracetamol to children aged two months or older, and ibuprofen to children aged three months or older who weight more than 5kg.
Make sure you buy paracetamol or ibuprofen suitable for your child’s age, and follow the instructions on the packaging carefully.
Meanwhile don’t give a child with asthma ibuprofen, and don’t combine ibuprofen and paracetamol unless your doctor advises you to do so (you can give them paracetamol if ibuprofen isn’t effective and vice versa, but not the two medicines at the same time). You should also not give a child ibuprofen if they have chickenpox or if they are dehydrated.
It’s also important to never give aspirin to children younger than 16 years.
If you are giving your child paracetamol or ibuprofen, it’s a good idea to keep a note of how much you give them and when you’ve given it, as it’s a handy way to make sure you don’t give them more than the recommended amount.

Can supplements help support my child’s health?

Often there’s little you can do to prevent infections in children that can cause fever. But making sure they have a healthy lifestyle that includes a balanced, nutritious diet may help keep their immune system strong. You could also consider boosting their diet with nutritional supplements that provide extra reassurance that they’re getting all the major nutrients they need for a healthy immune response.
Some of the supplements you may want to try include the following:
Multivitamin and mineral   These are ideal for children who are fussy eaters or who don’t always eat as healthily as they should. There are several multivitamins available for children and young people, so choose one for your child’s age group as it will have the right vitamins and minerals they need in the right amounts. If your child has difficulties swallowing tablets, try a chewable multivitamin or one that dissolves in water to make a tasty fizzy drink.
Vitamin D   Getting the right amount of vitamin D can help support normal immune function. Your child can get the vitamin D they need in a good multivitamin and mineral supplement, or you may want to give them a separate vitamin D supplement (vitamin D drops are handy if they don’t like taking tablets).
Public Health England recommends all children from birth to four years old take a daily vitamin D supplement throughout the year, while children over four years should take vitamin D during the autumn and winter months (or all year round if they don’t spend much time outdoors during the spring and summer or they usually wear clothes that cover up most of their skin when they’re out and about) (vi). Children with dark skin may also not get enough vitamin D from sunlight.
Vitamin C and zinc   A good-quality children’s multivitamin and mineral will also give your child vitamin C and zinc, which they need for immune function support (vii). As with vitamin D, you can also give your child separate vitamin C and/or zinc supplements – just check any supplement gives them the right amount of each nutrient for their age.
Fruit concentrates   Other supplements that may help keep your child’s immune system strong include natural concentrates such as elderberry, blackcurrant and rosehips, Not only are they good sources of beneficial antioxidant plant compounds, but elderberry, blackcurrant and rosehip concentrates taste delicious too. Look for products that are naturally sweetened, as children may find these more palatable than products that include artificial sweeteners.
If your child has a fever it can be very stressful. But knowing what  to look out for can be reassuring, as there’s a good chance your child’s fever won’t be harmful. Being able to spot the warning signs of a more serious illness could also mean your child would get treatment quickly if they needed it, helping them to make a complete and speedy recovery. If you’d like more information on children’s and adult’s health issues, take a look around our pharmacy health library.


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  7. Maggini. S., Wenzlaff. S., Hornig. D. Essential role of vitamin C and zinc in child immunity and health. J Int Med Res. (2010 Mar-Apr). 38(2):386-414. Available online:

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Disclaimer: The information presented by Nature's Best is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.

Our Author - Christine Morgan


Christine Morgan has been a freelance health and wellbeing journalist for almost 20 years, having written for numerous publications including the Daily Mirror, S Magazine, Top Sante, Healthy, Woman & Home, Zest, Allergy, Healthy Times and Pregnancy & Birth; she has also edited several titles such as Women’ Health, Shine’s Real Health & Beauty and All About Health.

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