Learning from fever

We have all experienced it in one form or another. A tiny little body crying and clingy that burns your hand when you try to comfort. Usually accompanied by a runny nose and a cough, but sometimes with no symptoms to explain the warm forehead. We all know we are supposed to measure the fever, and that it should be taken seriously, but when? And what should you do about it? Read on to learn a bit more about fever.

Your body temperature is controlled by the thermoregulatory center of the hypothalamus (a highly specialized area situated in the center of your brain). A normal body temperature of 37°C (up to 37.5°C in infants younger than 4 weeks) is maintained by balancing heat production (from metabolic activity in your liver and muscles) with heat dissipation (which mostly happen from your skin and lungs).


A kiss is the outward visible sign of an inward fever.

Minna Antrim

When there are intruders in your bloodstream (usually viruses or bacteria), your immune system responds by increasing the “soldiers” (some of which are called cytokines) to prepare for battle. The hypothalamus joins the fight by calling more troops (the prostaglandin “division”) and these troops actually fool the thermoregulatory center into thinking the body temperature is too low, and thus the “normal” setpoint for the body is raised. The body now produces more heat by increasing the metabolic rate (how fast your body uses O2, CO2, sugars to produce energy) and increasing muscle activity (this is why we shiver). At the same time the small veins in the skin contract to lose less heat, causing the skin to look pale or mottled.

Fever is thus a normal physiological reaction to an immune response in your body. Fever in itself is not bad, it even has some potential benefits. An increased body temperature decreases the growth and reproduction of bacteria and viruses. Studies have also shown that your immune response is more effective at higher temperatures. (This effect is however reversed at temperatures above 40°C). So what is the problem with fever? As I have explained fever increases your metabolic rate, and your body thus needs more oxygen, water and glucose and produces more carbon dioxide that needs to be breathed out. This increases the demands on your heart and lungs, and decreases the resources available for your brain. (Not great for a child with a chronic heart or lung disease, or someone prone to convulsions.) It also causes general discomfort for your child, hence the crying and clinginess.

Please remember that fever is ALWAYS a SYMPTOM of something else and needs to be investigated.

So what should you do? And when should you worry?? Here are some practical tips for you to follow:

  • How to measure a temperature:

Rectal measurements with an electronic or mercury- thermometer will always be the gold standard as this is the closest practical place that we can measure the core temperature of the body. (During surgery or in ICU we can also use the esophagus (swallowing tube) or bladder). We need these accurate measurements to make decisions in clinical treatment.

At home you only need to “screen” if your child has a fever or not:

In babies < 4 weeks the recommendation is to take a measurement in the axilla (armpit) with an electrical thermometer.

From 4 weeks – 5 years you can still use the above method, and using a thermometer that measures the temperature in the ear is also acceptable. These measure the heat produced by the tympanic membrane and are not quite as accurate, but very easy and quick to use.

The Infrared Contact/Non-Contact thermometers measure the heat on the forehead produced by the temporal arteries. Although these are very easy to use even on a sleeping baby, they are very expensive and studies about their accuracy are still very inconclusive.

  • When is it classified as a fever?

Temperatures of ≥ 38°C in babies under 3 months of age should always be investigated.

If your child is between 3-36months old, temperatures of ≥ 38°C is classified as a fever, but it is only of concern once it is ≥ 39°C (or ≥ 39.5°C in children older than 3years).

  • When should you see a doctor?
    • All babies under 3 months of age with a fever should be investigated for a possible serious bacterial infection. This could include blood, urine and csf tests. (CSF is a fluid that circulates around the brain and spinal cord and we need it to check for meningitis). It could also mean that your doctor will admit your baby and start with prophylactic broad spectrum antibiotics until the test results are known. I know this can be very stressful for you and your baby, but multiple studies have shown that in this age group fever can sometimes be the only sign of a serious bacterial infection such as meningitis or sepsis.
    • In older babies and toddlers, if the fever continues for more than 5 days it is better if a doctor can rule out common bacterial causes.
    • If any fever lasts longer than 14 days it is classified as a chronic fever and a cause should be found.
    • If your child has any of the following “red flag” symptoms with a fever, please see a doctor asap:
      • Drowsy/ difficult to wake
      • Extremely irritable / high pitched cries
      • A rash that does not blanche (lighten in colour) when you press a glass against it
      • Convulsions
      • Dehydration (sunken eyes or sunken fontanelle, dry mouth and eyes)
      • Fast or abnormal breathing
  • What can you do to treat the fever?

It is not necessary to treat all fevers. Unless your child has another chronic illness, the main reason for treating a fever is to alleviate their discomfort.

Ensure that you give your child extra fluids to drink and decrease their activity (perfect reason to snuggle on the couch with a cup of tea). Remove excess clothes (but do not uncover them fully) and give a lot of TLC. Sponging them down with lukewarm water could decrease the temperature, but is very uncomfortable and no longer advised.

Antipyretic medications such as Paracetamol and Ibuprufen works very well to decrease the temperature and at the same time has an analgesic (anti-pain) effect, so it usually helps your child to feel, eat, drink and sleep better.

Paracetamol dosage : 10-15mg/kg/dose every 4-6 hours. (Begins to work in 30-60min, lasts 4-6hrs).

Ibuprufen dosage: 10mg/kg/dose every 6-8 hours. (Begins to work in 40-60min, lasts 6-8hrs).

It is usually suggested to start treatment of a fever with Paracetamol (unless your child has specific contra-indications). If the fever remains high, and your child’s discomfort has not improved, switch to Ibuprufen. Some kids / causes of fevers respond better to the one or the other.

You could also alternate between the two types of medications, but this is not advised because of the risk of confusing the dosages. It is not necessary to wake a sleeping child to give the next dose of antipyretic medications, so rather give a proper dose just before bed-time.


30 Simon’s mother-in-law was in bed with a fever, and they immediately told Jesus about her. 31 So he went to her, took her hand and helped her up. The fever left her and she began to wait on them.

Mark 1:30-31

So when you feel that burning forehead, make sure you know what is causing it, give some antipyretic medication to make your child more comfortable, tell Jesus about it, and then give a lot of love and cuddles. I hope your little one will only rarely need this advice!

Resources used comes from the latest NICE and UPTODATE guidelines:

https://www.nice.org.uk/guidance/cg160/chapter/1-Recommendations#thermometers-and-the-detection-of-fever-2

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