The thermometer confirms what the parents already suspected from their experienced glance at their child's red cheeks and glassy eyes, as well as from feeling their forehead: the child has a fever. This is actually a good thing, because a higher body temperature means that the body is boosting its defences, i.e. it is doing its job.
But this is precisely what unsettles many parents. In this country, fever is the most common reason why parents take their children to see paediatricians, family doctors or emergency services in hospitals.
Please do not take your temperature constantly. It is completely normal for body temperature to fluctuate.
Ulrich Heininger, paediatrician
«It is important to note that fever is not an illness, but rather a symptom that indicates something else is going on,» says Ulrich Heininger. He is president of the Swiss Paediatric Infectious Diseases Group and professor of paediatric infectious diseases and vaccinology at the University Children's Hospital Basel. Fever itself is not dangerous, but the underlying illness that causes it may be.
This «possibly» is crucial, because it is very small: «In 99 out of 100 cases, fever is a symptom of an infectious disease,» says Heininger. «In very few cases is it caused by things like heatstroke, a tumour or an immune system disorder.»
Keep calm
Heininger can certainly understand the concern that a dangerous illness may be behind the fever. However, experience shows that in the vast majority of cases, this concern is unfounded. There are, however, warning signs that mean parents should waste no time and take their child to see a doctor immediately (see blue box).
Otherwise, the key is to stay calm. And above all, don't constantly take their temperature. It is completely normal for body temperature to fluctuate. «If you take their temperature regularly just because you suspect they might be ill, don't be surprised if your child has an elevated body temperature on 10 out of 20 days,» says Heininger.
You should only use a clinical thermometer if your child feels hot or you think they are ill. If the display shows at least 38.0 degrees Celsius – regardless of where it is measured – doctors refer to this as a fever.
First, observe your child: Are they drinking? Are they behaving normally, even if they are less active than usual? Are there any warning signs? If not, there is no cause for concern. For three days, the body can fight off bacteria and viruses with a fever. If the fever lasts longer than that, Heininger advises consulting your paediatrician or family doctor.
Body temperature
For most people, it is lowest at around two o'clock in the morning. It then rises slightly before waking up, but is still quite low in the morning. Most people reach their highest temperature in the afternoon.
Physically strenuous activities also have an effect and can increase core body temperature by up to 2 degrees Celsius. If our body temperature is temporarily below the normal range, experts refer to this as hypothermia; if it is above the normal range, the person affected has a fever.
The purpose of fever
What exactly happens in the body when you have a fever? As soon as pathogens enter the body, the immune system springs into action. It sends special messenger substances to the hypothalamus, a part of our brain, instructing it to raise the body temperature. To do this, it boosts the metabolism and activates the muscles so that they produce more heat. At the same time, heat loss through the skin is reduced, which is why you often have cold hands and feet when you have a fever.
An increased pulse and faster breathing are also consequences of the increased activity in the body. The heat generated activates additional defence cells that fight the pathogens. «If you imagine the defence against infectious agents as a concert, then fever is an important player,» says Heininger.
Allowing the immune system to do its job also means not immediately thinking about how to bring the temperature down again. Never lower the fever for the sake of lowering the fever, says Heininger, the focus should always be on the child's well-being. This means that even at 39.8 degrees Celsius, there is no need to treat the fever, even if the child is a little quieter and more exhausted than usual.
However, as soon as the parent sees that the child is suffering, it makes sense to reduce the fever. «And then it doesn't matter whether the thermometer reads 38.5 or 39.5 degrees Celsius,» says Heininger. Ibuprofen or paracetamol can then be given in the maximum dose permitted for the child's age. Both active ingredients have good fever-reducing properties.
Every child reacts differently
Eva Berger also experiences time and again how a child with a fever can cause great anxiety. As head of the emergency department at the University Children's Hospital in Zurich, she often encounters parents in the emergency room who tell her they know someone who lost a child to fever. She tries to reassure them, pointing out that the decisive factor is the child's general condition.
Is it still drinking? Is it still playing? Can it be calmed down? «Parents find it really difficult when I recommend doing nothing and waiting to see how a child who is running around and playing here feels in the next few hours – even though they have a temperature of 40 degrees.»
I advise against vinegar compresses. Concentrated vinegar on the skin can cause severe eczema.
Eva Berger, emergency doctor
In the few exceptional cases where doctors prefer to see children once too often rather than once too little, parents are already well informed: for example, because the child has an underlying heart condition or is immunosuppressed after a transplant or chemotherapy. Infants under three months of age with a temperature above 38 degrees Celsius should also be clinically assessed.
A common misconception among many parents is that the higher the fever, the sicker the child must be. «The height of the fever has nothing to do with the severity of the infection,» says Berger. Although the extent to which the body heats up does depend on the type of pathogen, it varies from person to person, as everyone has their own immune system. This is why one child may have frequent, rapid but short-lived fevers, while another may rarely have a fever but be affected for several days.
What to do in the event of a febrile convulsion?
The fact that parents of younger children in particular want to bring down a high fever quickly is also related to what are known as febrile convulsions. Febrile convulsions are seizures triggered by fever. A familial predisposition is known to exist.
Children between the ages of 6 months and 6 years are affected. Febrile convulsions occur suddenly and often when the fever first rises. The children lose consciousness, become stiff and experience rhythmic twitching throughout their bodies. Their eyes are open and often rolled upwards.
Anyone who has experienced this or heard about it from friends would like to prevent it. Unfortunately, however, this is not possible. There are no measures that can reliably prevent febrile convulsions. «The preventive effect of fever-reducing measures has not been proven, so we do not recommend this to parents,» says Berger.
When should one react?
- Consciousness is impaired, the child is acting unusually slow, and their gaze appears clouded.
- Punctiform haemorrhages on the skin that do not fade when pressed with a drinking glass.
- The child is sensitive to touch and cries out when touched or picked up.
- The child refuses to drink.
- Parents' gut feeling tells them that something is wrong with their child.
Drink plenty of fluids
The accelerated metabolism associated with high fever can lead to fluid loss, so children should be offered plenty to drink. «Because the total proportion of fluid in their bodies is significantly higher than in adults, they lose more of it when they have a fever,» says Berger. Calf compresses are only useful if the child's calves are really significantly warm. The water used for this should never be cold, but lukewarm. Otherwise, you will achieve the opposite effect. The younger the child, the faster they become hypothermic.
Eva Berger is not a fan of vinegar compresses, which are often recommended in relevant guidebooks: «I have seen some relatively severe cases of eczema caused by concentrated vinegar on the skin.»
Even though fever is a harmless symptom in most cases, many parents are unsure what to do when it occurs. Should they give their child something to reduce the fever or wait and see? When exactly is it an emergency? Is it an overreaction to go to A&E?
«No one should be afraid to pick up the phone and ask for advice in such a situation,» says Eva Berger. Good sources of advice include paediatricians or Kids Line, a medical helpline for children and young people in emergencies, which is run by specialist staff in collaboration with several children's hospitals and Medgate.
