Fever in children: Overview - InformedHealth.org - NCBI Bookshelf

InformedHealth.org [Internet].
Fever in children: Overview
Created: December 18, 2013; Last Update: June 6, 2019; Next update: 2022.
Introduction
"My child has a high temperature" – not an unlikely event in the lives of parents with young children. Children are more likely to get a fever than adults are. Fever is one of the most common reasons why children are brought to the doctor or to the hospital for out-of-hours medical advice.
Children are considered to have a fever if they have a body temperature of 38.5°C (101.3°F) or more, and babies under three months old are already considered to have a fever at a body temperature of 38.0°C (100.4°F) or more.
As a child's temperature increases, so does many parents’ concern for their child. But most children with a fever have a harmless virus. The child can then be cared for at home and will feel better again within two or three days. Their bodies can fight off the viruses without any extra help.
Only about 1 out of 100 children with fever have a serious medical problem that needs to be treated by a doctor. In most cases bacterial infections such as pneumonia are then to blame.
Symptoms
You can often tell that a child has a fever just by looking at them. Typical signs include a red face, tired-looking or glazed eyes and otherwise pale skin. A hot forehead or neck can also be a sign of fever. Some children lose their appetite or cry a lot.
It's important to take the child to see a doctor if
their temperature is above 39°C (102.2°F) or a baby under three months old has a temperature above 38°C (100.4°F),
the fever comes and goes,
the fever lasts longer than three days,
they have a febrile seizure,
they have a stiff neck, are unresponsive, restless or confused,
they vomit, have diarrhea or pain in their belly,
they have a skin rash,
they refuse to drink over a long period of time or
their condition has worsened since the last visit to the doctor.
Causes
Even things like running around, excitement or very warm clothing can make children’s body temperature rise, although they are not ill. One reason for this is that children don't sweat as much or as easily as adults do when they get warm. Teething can cause a child's body temperature to go up too.
But fever is usually caused by germs. It is a sign that your body is trying to fight them. So it isn't a medical condition. Instead, it is a reaction in the body to speed up certain metabolic processes and help the immune system fight faster.
A vaccination: because the child's immune system is developing antibodies to fight the germs that the vaccine aims to protect them from.
Dehydration: The child has a fever because they haven’t had enough to drink and their body is dehydrated. This kind of fever due to dehydration can also be caused by severe vomiting and diarrhea.
Sunburn, sunstroke or skin conditions such as hives (urticaria).
In rare cases: serious illnesses such as pneumonia, meningitis, appendicitis or an infection of the joints or bone marrow.
In very rare cases: metabolic diseases, rheumatic diseases or allergic reactions to foods or medications.
If a fever develops after traveling to a faraway place – even several weeks after returning – it's important to tell your doctor about your travels. Special tests can be done to find out whether the child picked up an infection while traveling.
Effects
Many parents worry that a high fever could become life-threatening. Fever alone is only rarely harmful and usually remains below 41°C (105.8°F). Higher temperatures can be dangerous, but they are rare.
Fever can lead to dehydration (too little fluid in the body). Medical help is needed if the child refuses to drink or shows signs of dehydration, such as the following:
A sunken fontanel (soft spot on the top of the baby's head)
A dry mouth and dry lips
Sunken eyes
Lack of tears
The child generally looks ill
Fever can sometimes lead to a febrile seizure (also known as a febrile convulsion) – particularly in children between the ages of three months and five years. Although simple febrile seizures can be very alarming, they usually only last a few minutes and are not dangerous. But it is still a good idea to take the child to see a doctor afterwards.
Diagnosis
Healthy children have a body temperature between 36.5°C (97.7°F) and 37.5°C (99.5°F). This temperature changes over the course of the day: It's usually about 0.5°C higher in the evening than it is in the morning. Temperatures between 37.5 (99.5°F) and 38.5°C (101.3°F) are referred to as an elevated body temperature.
It's considered to be a fever at temperatures of 38.5 (101.3°F) or more in children, and at temperatures of 38.0°C (100.4°F) or more in babies under three months old.
Body temperature can be measured in different ways. With small children it is particularly important that it can be done quickly and with as little effort as possible – such as dressing and undressing or keeping still. Many parents first place their hand on their child's forehead or neck to check whether it feels hot.
They can then use a thermometer to measure the child's temperature – ideally three times a day, if possible. The best way to get reliable readings is by inserting a digital thermometer into the child's bottom (rectal temperature). Many parents prefer to use a digital ear or forehead thermometer. You can also take a child's temperature in their mouth or under their armpit, but this is only suitable in children aged four and over. The length of time needed to take the temperature depends on where it is measured and what kind of thermometer is used – you will find further information in the instructions that come with the thermometer.
Treatment
When children have a fever, they often don't need to be given medication to lower it.
But treatment with fever-reducing medication such as acetaminophen (paracetamol) or ibuprofen can help if the child has a high fever – above 39.5°C (103.1°F) – or is feeling very unwell. This medication can be used in the form of a syrup or a suppository. The correct dose will depend on the child's age and body weight, as described in the package insert. If the fever is treated with paracetamol or ibuprofen but still hasn't gone down after one to four hours, it's best to seek medical advice.
Acetylsalicylic acid (the drug in e.g. Aspirin) can cause a rare but dangerous side effect called Reye’s syndrome in children and teenagers. So children shouldn't use acetylsalicylic acid unless the doctor says it's okay to use it.
Home remedies such as cooling the child's lower legs with wet towels or giving the child a lukewarm bath are popular but they only cool the outside of their body. If the child says it feels good, there's no harm in doing these things. But it's not clear whether they really help to reduce the fever.
It's more important not to dress the child too warmly, otherwise their body won't be able to cool off.
Everyday life
Most children with a fever can be well cared for at home. If your child doesn’t have any of the signs of a serious illness described above, or if the doctor has diagnosed a harmless infection, there's no reason not to care for him or her at home.
Children who have a fever need to get enough fluid. So it's important to make sure that children, including those that are breastfed, drink enough. Children have a pretty good feel for what's good for them. So it's a good idea to ask them what they need – for instance, what they feel like eating or drinking.
Children may play all day long despite having a fever. As long as they don't run around too much, that's perfectly fine. A child with a fever is ill and shouldn't go to playgroups, kindergarten or school. This is true even if they seem to be fine otherwise. They could still infect others.
When children have a fever, it nearly always goes away again on its own. Time, rest and loving care are usually the best remedies.
Further information
When people are ill or need medical advice, they usually go to see their family doctor or pediatrician first. Read about how to find the right doctor, how to prepare for the appointment and what to remember.
IQWiG health information is written with the aim of helping
people understand the advantages and disadvantages of the main treatment options and health
care services.
Because IQWiG is a German institute, some of the information provided here is specific to the
German health care system. The suitability of any of the described options in an individual
case can be determined by talking to a doctor. We do not offer individual consultations.
Our information is based on the results of good-quality studies. It is written by a
team of
health care professionals, scientists and editors, and reviewed by external experts. You can
find a detailed description of how our health information is produced and updated in
our methods.