Fever in Children: What Helps, and When to See a Doctor

Fever is not an illness but a symptom that tells us something is happening in a young child’s body. It is the body’s main defence mechanism against pathogens, one in which the activity of the immune system increases. Its purpose is to eliminate the enemy – a viral or bacterial pathogen – as quickly as possible. However, if a high temperature (above 38.5 °C) persists for a long time and cannot be brought down, there is a risk of complications such as febrile seizures, dehydration, loss of appetite or constipation. In this article you will find answers to your questions, including when it is best to give medicine for a high temperature.

Fever is a common reason for seeing a doctor. In about 1 in 5 children with fever, however, no clear cause can be identified. Most of these children have a viral illness that will clear up on its own. But fever can also be caused by a bacterial infection. Fever that is not caused by an infection is generally less common in children. Even so, it is important to understand the cause of the fever.

01 Causes

Fever is a sign of an inflammatory response in the body and can occur with bacterial or viral infections. A moderate rise in temperature to < 40 °C supports the immune response. Non-infectious inflammatory reactions are also accompanied by fever, for example rheumatic diseases such as juvenile idiopathic arthritis, chronic inflammatory bowel diseases (Crohn’s disease, ulcerative colitis) or Kawasaki disease. With these conditions it is important to see highly qualified doctors. Treatment in Switzerland draws on all the latest international advances in paediatric care, so fever of unclear origin can be investigated and the correct diagnosis made.

02 What can you do yourself?

Newborns and babies under 3 months old should be seen by a paediatrician urgently if they have a fever. If your child is suffering badly from the fever, from accompanying symptoms or from an underlying condition, you should also see a doctor in any case. The same applies if the fever lasts longer than a day, cannot be brought down with fever-reducing medicines, or if febrile seizures or other signs of illness occur, such as diarrhoea, vomiting, abdominal pain and so on.

03 Take the temperature – but take it correctly

If you suspect a fever, take your child’s temperature straight away. The most accurate readings come from rectal measurement, in which a thermometer is gently inserted into the child’s bottom. The following procedure is recommended:

• The child is not overheated (from playing) and is wearing no more clothing than necessary (clothing that is too warm can mimic a fever).
• The child lies relaxed on their side with their legs drawn up; babies are laid on their back.
• Moisten the tip of a digital clinical thermometer with water or lubricate it with a little petroleum jelly or cream.
• Gently insert the thermometer one to two centimetres into the bottom and wait for the signal that the measurement is complete.
• Remove the thermometer, read it and clean it.

Another method is to take the temperature with an ear thermometer. Here it is important to hold the device correctly so that the infrared beam reaches the eardrum. To do this, gently pull the outer ear backwards and upwards. Note also that earwax and draughts can distort the reading.

A further method for cooperative children over the age of 5 is to take the temperature in the mouth. It is measured under the tongue no earlier than 10 minutes after eating or drinking, and the child should breathe through the nose during the measurement. Readings taken under the tongue are about 0.3–0.5 °C lower.

Note: forehead and temple thermometers, as well as measurements taken in the armpit, are inaccurate.

04 When should a fever be brought down?

Fever has an important job during infections: it speeds up all metabolic processes and so properly fires up the immune system. It therefore does not necessarily need to be fought – quite the opposite: studies have shown that fever-reducing medicines often prolong the course of infectious illnesses. On the other hand, a very high temperature is clearly harmful: if it rises above 39 °C, the boost in metabolism places an increased load on the heart and circulation. For this reason, many doctors recommend fever-reducing medicines earlier for children with heart or lung conditions than for healthy children.

So when should parents give their child a fever-reducing medicine?

There are no general recommendations for temperatures below 40 °C. Besides the measured temperature, the child’s general condition is decisive, which is why parents need to keep a close eye on their little patient. If the child is alert and drinking enough, a body temperature of up to 39 °C may also be acceptable. Parents of children in nappies should check regularly that the nappies are wet enough, i.e. that the child is passing enough fluid. Dry mucous membranes – for example, when the lips become dry and the child’s mouth feels sticky – are also good indicators that the child is not getting enough fluid. If in doubt, always consult a doctor.

05 Fever medicines: yes or no?

If quick relief is needed, a fever-reducing medicine may be the answer. Suppositories are best for young children because they do not have to swallow anything.

Most contain the mildly pain-relieving and fever-reducing substance paracetamol, whose effectiveness and tolerability are well documented. However, the stated doses must be followed strictly, as paracetamol can otherwise damage the liver.

The active substance ibuprofen is also considered safe and works in a similar way to paracetamol. However, ibuprofen for children usually comes as a syrup, and the active ingredient is generally suitable only from six months of age.

Never give a child with a fever acetylsalicylic acid (ASA, found for example in aspirin) without consulting a doctor, as this active substance can trigger Reye’s syndrome – a very rare but often fatal disease of the liver and brain.