What to do when your child’s fever goes above 40 degree Celsius?

[By Big C]

First of all, please check and ensure that your thermometer is working! Make sure you have the replacement batteries too. You wouldn’t want to be caught with a non-functioning thermometer when your kid is burning hot!

Big E’s temperature went up to 40.2 degrees celsius couple months ago

I had a several encounters with the scary 40 degree Celsius (temperature taken with BRAUN – ThermoScan® No touch + forehead thermometer) but only twice, I rushed them to KK Hospital. Let me share with you the scenarios and my reaction…

Some background about the kiddos’ body conditions…

Big E had her very first fever when she was 13 months old and it was due to bronchiolitis. She was not exclusively breastfed and was taking both breast milk and formula right from the start.

She does get sick every now and then but she doesn’t develop most of the time! Even post vaccination, she only developed fever after MMR too. So when she gets hot, it means serious business.

Her response to fever is also epic! Unless it’s like 40 degree celsius or she is really very sick, she will be just as active and bubbly as her usual self.

Small E, on the other hand, is very prone to fever. He got his first fever from his first 5-in-1 jab. He was exclusively breastfed till he turned one where he gets formula occasionally when I needed to leave him with my parents and I couldn’t send my ebm (expressed breast milk) to them in time.

I lost count of all his fever because sometimes he gets the fever before his other flu symptoms kick in, and other times he gets it after prolonged runny nose. Be it, mild or serious, fever has been his best buddy.

And he is very sensitive to fever. He tends to whine and get cranky even when running low grade fever.

My take on fever

Fever is only a symptom that signify some kind of infection so I am usually concerned with finding out what is the root cause. For example, if the kids are having runny nose, I would know it’s likely a cold. If they start to wheeze, then alright, that’s more serious – bronchiolitis. I get very worried if I cannot find any apparent symptom!

I do not believe in feeding fever medicine – be it paracetamol or ibuprofen unless my kid displays signs of discomfort. I have always been advised (by the elders) to feed them the medication on regular basis to keep the fever away.

Somehow, the elders have the mentality that the child does not recover soon after medicine is because we did not administer it every 6 hourly sharp! But in the case of Small E, when he gets cranky the moment his temperature rises, I would promptly feed him with paracetamol.

I am also aware that temperature tends to spike in the night so I am able to stay calm till day break even when I see high readings through the night.

And I prefer to feed the medicine only when they are very sick. I also like to not feed the fever medicine by the clock because I wanted to see my kids’ real reaction.

Of course, mummy instinct and other observation are just as important in helping me assess the situation before deciding what to do next.

Big E’s fever history

There are only 2 “memorable” occasions over the past 4.5 years.

She was 14 – 15 months old or so when she had this high fever. It was my first encounter with a persistent 39.8 degree celsius in the night and even after paracetamol, the temperature hardly dropped. She was all sleepy, as expected for someone with such high temperature. BUT I couldn’t tell what was wrong because she wasn’t having any flu symptoms at all.

I wondered if it was UTI (urinary tract infection) and as I looked at the clock, I guess it’s better now than later since the KKH’s A&E is likely to get more and more crowded.

And so we went the hospital and there was nothing found! Her lungs were clear, nose was clear, ear was clear and even urine test turned out fine. And she was responding well to the ibuprofen that they fed. So we were good to return home to monitor.

I did asked the doctor how should I manage high fever in future. Do I need to rush her in every single time? Doctor told me that it is actually alright to monitor at home for temperatures even up to 40.5 degC , but most importantly, we need to observe her behaviour.

If she is not lethargic and not able to respond to us, then she should be fine. But he did also say that if unsure, always feel free to bring her in.

That gave me confidence for the future fevers.

Two days later, her fever subsided and rash appeared. It looks just like Roseola! I just let the rash subside on its own and she is all good again.

The second time happened just couple months back. It’s been a long time since she got any fever. She was having flu and a bad cough. This fever went up high in the night and she started getting cranky and even hysterical. She whined and cried.

I know the behaviour was only due to the temperature so I didn’t plan to bring her to the hospital. But I stayed in her room through the night, sponging her and taking measurement every hour. She would scream out of sudden in her sleep. I can only imagine how bad she must have felt.

The fever went away after day break and she was well except with that nasty cough. I kept her at home for another day just in case her fever comes back again. Then it’s ME who was struggling to stay awake… haha after a sleepless night..

Thankful that nothing serious happened to her though the number 40 on the thermometer really scares the shit out of parents!

Small E’s fever history

I lost count of Small E’s fever episodes! My childcare leave, family care leave, annual leave all burnt for the year and were mostly taken due to his fever. And his fever tends to stay for about 2 days, sometimes without much symptoms and it’s just low grade fever.

And I have also two “memorable” episodes with Small E. Both times I rushed him to KKH. The first time was about 4 months back? He was running high fever and 4 to 5 hours after paracetamol dose, his temperature will start to rise. We were at my in laws place and everyone was questioning my decision of not feeding the medicine promptly – every 4 hourly. So his temperature was high and he was sleeping. I caved in and decided to use the suppository (Diclofenac sodium).

20 minutes later, he was turning blue!

His limbs were cold and he was still sleeping. He didn’t wake to respond to my calls. While I carry him to assess his situation, he trembled! My turn to shiver… and I told my husband, we must go NOW!

When we arrived at the hospital, the nurse asked us questions which I believe was to assess if he was having febrile fits. They weren’t too anxious but I was still directed to a doctor sooner than usual. Their initial diagnosis was HE WAS COLD. They didn’t dismiss us but gave us blanket and told me to wrap around Small E and observe. The doctor did come back every 5 to 10 min to check on him.

Indeed, he started turning pink and soon he woke up!

So the doctor was right! He was just feeling too cold. Awww.. I felt relieved and embarrassed at the same time but the doc told me I was right to bring him in as we would never know..

Later when we pick up the medication which includes the suppositories too. I was shocked! The prescription was half every 12hourly. My GP’s prescription was one full tab! Though doc told me unlikely it’s drug allergy, I wonder if it was a sign of overdose.

Whichever the case, I made mental note about this medication.

The second episode was just last week! He started having low grade fever with some flu symptom. So we got medicine from the GP and he was well the next day. But that night, he started having fever again and it ran high. He wasn’t responding well to paracetamol.

It went on for another 2 days and I decided to use the suppository again. His fever subsided in 30min and his head was wet from perspiration. I was relieved like finally he can feel better and hope as he recovers, the temperature will start lowering. But in less than 2 hours, his temperature was back at 40degC!

Now, I am starting to get worried. I was considering if I should bring him to the hospital immediately or should I try sponging him and perhaps he will get better after his nap?

After awhile, I went to measure him and the forehead thermometer went from 40.5 to 41.5 to ERR!!

I called my hubby immediately and said we need to bring him to the hospital now! Thankfully the A&E dept was not crowded and waiting time wasn’t super long. We saw the doc and blood test was done. Test results showed that it was just viral. Doc decided to listen to his breathing again and she said she could hear subtle cackle. So she suggested X-ray for the lungs.

The X-ray showed that there was inflammation and mild infection. Another senior doc joined us and checked Small E again with the results. He agreed with the diagnosis of chest infection and since the symptoms matched pneumonia, they decided to treat it like pneumonia though it’s not.

We were given some paracetamol, ibuprofen and 6 bottles of amoxicillin! He has to be on 10-day course of antibiotics, 3 times a day and each feed is 11.4ml! I can’t imagine the feeding process for 10 days… (thank god it turned out pretty okay!!)

As I am writing, he is still on the course but he is all well now. I am happy that I made the decision and I met meticulous doctors who made careful checks for him. With the right medication, his fever went off within 48hrs.


  1. Take note of when the fever starts and the temperature fluctuation.
  2. Observe if there is any other accompanying symptoms.
  3. Allow your child to rest / sleep as much as possible.
  4. Hydrate as much as possible.
  5. Observe the temperature changes after every medication feed. Refer below for the general guide on how to administer the different fever medicine.
  6. You may observe temperature spike in the night. Use your judgement to decide if a hospital trip is necessary. I dare not say it is safe or not as it depends on each child’s condition and overall symptoms.
  7. When in doubt, go to the hospital. Do take note that not all Hospitals can administer medication to children (below age of 14).

Do you have any scary encounters with your child’s fever too? Comment below or email me to share!

General guideline (from both HealthXchange and KKH)


  • First line of medication to be used, can be given every 4-6 hours
  • Every 4 hours if temperature above 39 °C
  • Every 6 hours if temperature less 39 °C
  • Do not use in infants less than 3 months old


  • Use only when fever is persistently above 39 °C, 1 – 2 hours after paracetamol
  • Given every 6 hours
  • Do not use in infants less than 1 year old, unless advised by your doctor

Diclofenac Na (Voltaren suppositories)

  • Use only when fever is persistently above 39 °C, 1 – 2 hours after paracetamol
  • Given every 12 hours
  • Do not use in infants less than 1 year old, unless advised by your doctor

Do not give your child:

  • Both ibuprofen and diclofenac at the same time as they belong to the same class of medications.
  • Either ibuprofen or diclofenac if there is any severe vomiting or bleeding disorders, in view of possible bleeding from the stomach and intestines.
  • An anti-pyretic usually brings down the temperature by 1 – 2 °C. Do not be alarmed if your child is still having a fever after the medication. Antibiotics are of no use in viral fevers.
  • Do not use Aspirin in children.

Consult your doctor when your child:

  • Is feeding poorly, vomiting or lethargic
  • Is very young, especially less than 3 months old
  • Has difficulty breathing
  • Is drowsy
  • Looks sicker than previously
  • Has abdominal pain and discomfort
  • Has rash
  • Has decreased urine output

Do seek doctor’s advice at your discretion. Do not attempt self-medication unless you have been advised by your doctor before. It’s never wrong to play it safe. 

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