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.

Many parents start to worry if their child has a rising temperature. And they may wonder whether they need to see a doctor or go to the emergency room. But you can hold off at first: 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.

At a glance

• Most children with a high temperature have a harmless viral infection.
• Children are considered to have a fever if they have a body temperature of 38.5°C or more, and babies under three months old have a fever at a body temperature of 38.0°C or more.
• The best way to get reliable readings is by inserting a digital thermometer into the child's bottom (rectal temperature).
• You don't need to see a doctor or go to the hospital if the fever isn't that high.
• Only about 1 out of 100 children with fever have a serious medical problem.
• Certain signs can help you decide whether you want to first wait and see.

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 is necessary to take the child to see a doctor or to the emergency room if

• their fever rises to over 39 °C (or over 38 °C in babies),
• comes and goes or
• 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 feel warm without having a fever or being ill. One reason for this is that children only start sweating later in life as adults.

Teething can cause a child's body temperature to go up too.

But fever is usually caused by germs. Instead, it is a reaction in the body to speed up certain metabolic processes and generate more warmth. So it isn't an illness, but rather part of your body's normal response to the germs.

Possible causes of fever include the following:

• Viruses or bacteria: for instance, a common cold, middle ear infection, urinary tract infection (UTI) or gastroenteritis. Or typical childhood diseases such as mumps, measles, German measles (rubella), scarlet fever, chickenpox and sixth disease (roseola).
• 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 or diarrhea.
• Sunburn and sunstroke.
• 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.

A child with fever sweats more. That 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 is 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 is 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

A child with a fever usually won't need to take fever-reducing medication.

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.

Box

Children shouldn't use acetylsalicylic acid unless the doctor says it's okay to use it. This is because it can cause a rare but dangerous side effect called Reye’s syndrome in children and teenagers.

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 is 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. In our topic "Health care in Germany" you can read about how to find the right doctor – and our list of questions can help you to prepare for your appointment.

Sources

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• Lim J, Kim J, Moon B et al. Tepid massage for febrile children: A systematic review and meta-analysis. Int J Nurs Pract 2018; 24(5): e12649. [PubMed: 29744960]
• Massignan C, Cardoso M, Porporatti AL et al. Signs and Symptoms of Primary Tooth Eruption: A Meta-analysis. Pediatrics 2016; 137(3): e20153501. [PubMed: 26908659]
• Meremikwu MM, Oyo-Ita A. Paracetamol versus placebo or physical methods for treating fever in children. Cochrane Database Syst Rev 2002; (2): CD003676. [PMC free article: PMC6532671] [PubMed: 12076499]
• Meremikwu MM, Oyo-Ita A. Physical methods versus drug placebo or no treatment for managing fever in children. Cochrane Database Syst Rev 2003; (2): CD004264. [PMC free article: PMC6532675] [PubMed: 12804512]
• Mewasingh LD. Febrile seizures. BMJ Clin Evid 2014: pii: 0324. [PMC free article: PMC3908738] [PubMed: 24484859]
• National Institute for Health and Care Excellence (NICE). Fever in under 5s: assessment and initial management. (NICE Clinical Guidelines; No. NG143). 2021.
• Offringa M, Newton R, Nevitt SJ et al. Prophylactic drug management for febrile seizures in children. Cochrane Database Syst Rev 2021; (6): CD003031. [PMC free article: PMC8207248] [PubMed: 34131913]
• Wong T, Stang AS, Ganshorn H et al. Combined and alternating paracetamol and ibuprofen therapy for febrile children. Cochrane Database Syst Rev 2013; (10): CD009572. [PMC free article: PMC6532735] [PubMed: 24174375]

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