Does My Child Have a Fever? How to Take a Child’s Temperature

Today is October 2nd and suddenly it’s really cold and rainy out! I am still holding out and wearing shorts but will probably give in when the thermostat goes below 45. At work, this can only mean a flood of patients with runny noses, coughs and general upper respiratory symptoms not to mention fever. I want to specifically talk about fever because so many parents ask themselves, “Does my child have a fever?” and take their children on an ER trip for just that reason.

So two things come to mind;

  • What a fever is exactly
  • How to take a child’s temperature

Fever Defined;

Normal body temperature is about 98.6 Fahrenheit or 37 Celsius. A fever is defined as 100.4 Fahrenheit or 38 Celsius. Fever is not a bad thing in and of itself and is a way for your child’s body to fight off infection. Kids can tolerate ridiculously high fevers and still look fine while we would be passed out in bed. I often tell parents of children that fever isn’t what should worry you. It’s more how your child appears. Is your child playful and active or is your child listless and lethargic? Your child’s physical appearance is more concerning than the height of their fever.

This of course doesn’t apply to infants under 2 months whose immune systems aren’t quite developed yet.

How to Take A Child’s Temperature (Fact and Fiction)


“I can tell that my child has a fever just by feeling them”. This is a called a “tactile temperature”. A very nice study published in the British Medical Journal looked at 409 children under age 5 years and assessed whether their mothers could determine if they had a fever just by touch. The study concluded that assessment of fever by touch was not particular accurate and that fever should be confirmed by more objective means. Bottom line is that you should not rely on touch to determine if your child has a fever or not. Invest in a thermometer and learn how to take a child’s temperature.

Objective Ways to Take Temperature (Fact)

There are many different products on the market for taking your baby or child’s temperature, so many in fact, that it can be down right confusing.

Rectal -Rectal temperatures are the most accurate, and what we use in the emergency department for infants (under one month of age). In the old days, we used to use mercury thermometers, but the safe and recommended way to go is a digital rectal thermometer. Safety First makes a nice one for infants. You should go with a rectal temperature if your baby is 3 months or under. Axillary – Axillary or armpit temperatures aren’t terribly accurate. Axillary temperatures usually run 0.5 to 1 degree F(or 0.3 to 0.6 celsius) less than your actual temperature.

Oral – Oral temperatures are taken with the thermometer under the tongue. This method brings back childhood memories of drinking hot soup before having my temperature taken so I could fake a fever. You can only consider this in children 5 years and older who can reliably keep a thermometer under their tongue. Oral temperatures usually run 0.5 to 1 degree F lower than rectal temperatures (or 0.3 to 0.6 less celsius). Ear (tympanic) – Ear temperatures tend to be fairly accurate but cannot be used reliably in children under 3 months because their ear canals are too small.

Temporal Artery Thermometers – These are relatively new thermometers. A study published in JAMA Pediatrics demonstrated that these thermometers are definitely more accurate than tympanic thermometers, but rectal thermometers are still the way to go with babies under 3 months of age. We actually use temporal artery thermometers in the emergency department!

The one thing to note with any of these methods is that you must read the instructions on the thermometer you are using. Also a squirmy baby or child can definitely throw off your temperature reading!

Managing a Fever

I’m not going to go into too much detail right now except to say:

  • You can alternate motrin (ibuprofen) with tylenol
  • You should not give motrin to babies under 6 months
  • Be careful with your tylenol dosing and frequency. Tylenol overdose is a serious thing!
  • Do not give children aspirin!
  • Do not rub your child down in rubbing alcohol. The alcohol is absorbed by the skin and can result in respiratory arrest! (I actually had a patient like this once).
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Looking for something specific? Write to Dr. Audrey Paul and let her know what topic you're interested in learning more about.


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