Fever isn't an illness in itself but is usually caused by a virus or bacterial infection. Fever is thought to be part of your body's natural response to an infection.
Fevers are common in young children. They are usually caused by viral infections and clear up without treatment. However, a fever can occasionally be a sign of a more serious illness, such as a severe bacterial infection of the blood (septicaemia), urinary tract infection, pneumonia or meningitis.
If your child has a fever, he or she will have a body temperature of 38°C or above. As well as having a high temperature, your child may also:
In some children, a fever can lead to seizures (fits) called febrile convulsions. During a febrile convulsion, part or all of your child's body may shake and twitch and your child’s eyes may roll back in his or her head. He or she may lose consciousness, and may be confused immediately afterwards. Febrile convulsions don’t usually last for longer than a couple of minutes and some last only a few seconds, but others can continue for up to 15 minutes.
Although febrile convulsions can be frightening, there is no evidence to suggest that they cause brain damage and your child is likely to make a full recovery. See our frequently asked questions for more information.
Fever can occasionally be a sign of a serious infection. Take your child to hospital or contact your GP immediately if your child:
It’s also important to contact your GP if your child’s fever:
Most fevers are caused by common viral infections, such as the common cold or flu, and go away on their own. Sometimes a fever can be caused by something more severe, such as an ear, bladder or kidney infection. Rarely, a fever can be a sign of a serious illness, such as meningitis or septicaemia.
Very rarely, children may develop a fever as a symptom of a condition other than an infection. For example, certain autoimmune disorders or cancers may cause a fever. If this is what is causing your child’s fever, it’s likely to last for longer than one associated with an infection.
Fever can also be a side-effect of some childhood immunisations. See our frequently asked questions for more information.
Depending on your child’s age, you can check his or her temperature from the ear, mouth (only if your child is over five) or armpit. You will need to take your child's temperature from under the armpit if your he or she is under the age of five, but bear in mind that these measurements are less accurate as the armpit is slightly cooler.
To take your child’s temperature this way, place the thermometer under his or her armpit, directly against the skin, and hold his or her arm gently against the chest. To take your child’s temperature by mouth, place the thermometer under his or her tongue for two to three minutes. Some digital thermometers will beep when they are ready.
Mercury thermometers are no longer recommended because there is a risk the thermometer could break and release the mercury, which is poisonous, into your child's body.
If your child has a temperature of over 38°C and is unwell, for example, floppy or irritable, contact your GP. This is especially important if your child is aged three months or younger. It’s also important to contact your GP if your child has any of the symptoms of a serious infection, even if his or her temperature isn’t particularly higher than usual.
Your GP will ask about your child's symptoms and can advise whether your child needs to be examined. If so, he or she will take your child’s temperature and measure his or her breathing and heart rate. Your GP will also ask about your child’s medical history. It may help if you keep a record of your child's temperature and other symptoms so that you can give clear information to your GP.
There is likely to be an obvious cause for your child’s fever, so he or she may not need to have further tests. However, if your child’s fever lasts longer than a few days and the cause isn’t clear, your GP may also take a urine and/or blood sample. If your GP is concerned about your child’s symptoms, he or she may be referred to a paediatrician (a doctor who specialises in children’s health).
Usually, your child's fever will be caused by a viral infection and will get better on its own. Monitor your child's condition by keeping an eye on his or her behaviour and whether he or she has any symptoms other than a fever. You don’t need to keep checking your child’s temperature if he or she is otherwise well, but if your child has a fever that lasts for more than five days, contact your GP.
Many parents and carers spend a lot of time trying to bring down their child’s fever. However, a fever is part of the body’s natural response to infection and can often be left untreated provided your child isn’t distressed.
Children who have a fever are often at risk of dehydration, so try to encourage him or her to drink to prevent this from happening as it can lead to more serious problems. As a guide, your child's urine should be pale yellow – if it's darker, or your child passes urine less frequently, he or she may need to drink more fluids. See our frequently asked questions for more information.
Your child is likely to feel more comfortable if you dress him or her in lightweight clothes and reduce the number of bedclothes used to cover him or her. This will enable your child to lose heat more easily. Although it’s important that your child doesn’t overheat, take care to ensure that he or she isn’t underdressed either. Don’t actively try to cool your child, for example with sponging or a cool bath, as this isn’t effective and may cause him or her to start shivering.
Keep your child away from school or nursery while he or she has a fever.
If your child is over three months old and is distressed by the fever, you can try giving him or her paracetamol or ibuprofen. This may help to make your child feel better.
Make sure you keep a note of how much paracetamol or ibuprofen your child has had and be careful not to exceed the safe dose. It’s important that you don’t give your child paracetamol and ibuprofen together but if the first medicine you try doesn’t help, you can try the other one later.
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.
If your child is dehydrated, he or she may have a dry mouth, pale and mottled skin, sunken eyes, reduced urine production, and no tears when he or she cries.
You become dehydrated when there isn't enough water in your body. This can happen to your child if he or she has a fever, so it's important to check for signs of dehydration.
Signs of dehydration include:
You may notice that your child is passing less urine than usual or has fewer wet nappies. A baby may also have a sunken fontanelle (the soft spot on the top of his or her head) – you may be able to feel this gently with your fingertips.
Encourage your child to drink fluids regularly 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 and associated fits (febrile convulsions or seizures), but the chance of this happening is very small. It’s very important to remember that any side-effects your child has as a result of immunisation will almost always be less severe than the symptoms that would be caused by the disease he or she is being vaccinated against.
Fever is a possible side-effect of some childhood immunisations. For example, the measles, mumps and rubella (MMR) vaccine can cause fever in children. Rarely, your child may get a fever about a week after he or she has the MMR injection, which can last for a few days. You can usually look after your child at home, but contact your GP if you’re concerned about his or her symptoms.
Even more rarely, the MMR vaccine can cause your child to have a febrile convulsion, again about a week after the vaccination. If your child has a convulsion after his or her vaccination, contact your GP immediately.
It’s important to remember that the risk of your child having a febrile convulsion after the MMR vaccination is much lower than the chance of one if he or she becomes infected with measles. Research has shown that there are no long-term effects in children who have had a febrile convulsion.
It can be frightening if your child has a febrile convulsion but they aren’t usually harmful. However, your child may get injured if he or she falls or chokes, so it’s important to make him or her as safe as possible. Stay with your child throughout the convulsion and try to time how long it lasts.
A sudden increase in body temperature can sometimes lead to seizures in children (also known as fits), which are called febrile convulsions. During a febrile convulsion, part or all of your child's body may shake and twitch and his or her eyes may roll back in the head. It’s possible that your child will lose consciousness during the seizure.
Although febrile convulsions rarely last longer than a few minutes, they can be very frightening. If your child has a febrile convulsion, try to stay calm. Don’t restrain your child but try to make him or her as safe as possible, preferably on a soft surface. Loosen your child’s clothing if you can, and try to remove anything in your child’s mouth, such as food or a dummy, as this could cause choking.
Your child may be confused immediately after the convulsion, but he or she is likely to make a full recovery. Even though febrile convulsions don't usually cause any lasting problems, it's important to keep a close eye on your child both during and afterwards, especially if it's the first time that your child has had one.
If your child's convulsion lasts for more than five minutes, call for emergency help or take him or her to your nearest accident and emergency department. If the convulsion lasts for less than five minutes, contact your GP for advice. It’s also a good idea to contact your GP if this is the first time your child has had a seizure.
About one third of children who have a febrile convulsion will go on to have another. Although febrile convulsions can be frightening there is no evidence to suggest that they cause brain damage and your child is likely to make a full recovery.