Fever: A Quick Guide For Parents

Adapted from a post by Natasha Burgert, MD

One of the most common reasons parents are calling or coming to the office is FEVER. Fever can make a kid look and feel lousy, which is not fun for a parent to watch.

First, A Few Fever Facts

A fever is a temporary rise in body temperature due to illness. Most consider a fever to be 100.4F degrees or higher (regardless of your child’s “usual temperature”).

Fever is a symptom of illness, not a disease. With very specific exceptions, fever is a normal, healthy way for the body to fight common infections. Bacteria and viruses that attack our bodies love normal body temperature, but cannot successfully replicate in hotter conditions. Fever reflects a robust immune system’s defense against these pathogenic attackers. The bacteria and viruses are the enemy, not the fever they cause.

It’s not your imagination – Fevers are worse at night. Our body systems follow a circadian rhythm. During the day, our level of cortisol (a stress hormone) is typically higher, slightly suppressing the work of the infection-fighting cells in our blood. At night, when cortisol levels drop, the immune system ramps up. When our immune system is working harder, higher fevers and more symptoms of illness can result.

Top 10 Fever FAQs

1. What is the best way to take a child’s temperature?

For healthy babies under two months of age, it’s okay to use an armpit thermometer to quickly screen for a fever. A simple digital thermometer will work. If a baby’s armpit temp is 99F degrees or higher, then a rectal temperature must be done to confirm your baby’s temperature. (Here’s a how-to video from Mount Sinai.) If the rectal temperature is 100.4F degrees or higher, call your pediatrician immediately or go to your nearest emergency room.

  • For kids over two months, an armpit thermometer remains a good option for screening. If the temperature is over 99F degrees, you can confirm a fever with a rectal or forehead (temporal artery) thermometer.
  • After six months of age, ear thermometers become an option, but can have some variability in accuracy. You’ll have the best chance of getting a correct temp by gently pulling your child’s ear up and back, while aiming the tip of the ear probe between the opposite eye and ear. Check both ears, and assume the higher temperature is correct.
  • Over the age of four years, an oral digital thermometer is thought to be the most accurate. Make sure your child has not consumed anything cold or hot for at least 15 minutes before taking a temperature. Ear and forehead thermometers are also great options for this age.
  • In our office, we use a simple digital thermometer to get rectal temperatures on our infants and a professional grade temporal scan thermometer for older kids (for home use try the brands Braun and Exergen.)
  • Warning: Forehead fever strips and pacifier thermometers are not very accurate, so save your money.

2. Is it true that the higher the fever, the more I should worry?

Although a high fever may indicate more serious illness in an adult, this is not the case for young kids. A young child’s immune system is always on high alert, and any sign of illness can result in a significant immune response.

Regardless of the actual numerical value, look for signs of serious illness in your child. Some kids appear fairly normal with really high temperatures, while others are sluggish and sad with a reasonably mild fever. Observe the amount of discomfort, level of activity and ability to maintain adequate hydration. Those symptoms are more important than the number itself.

3. When do I take my child to the doctor for a fever?

Over two months of age, most fever can be safely treated at home with fever reducing medication, hydration and patience. The fever caused by most viral illnesses of childhood are typically seen at the beginning of an illness, associated with other symptoms and last about 72 hours. But, there are few instances when pediatricians definitely want to see your child with fever.

It’s time to go to the doctor when: 

  • your child is less than two months old and has a fever of 100.4F or greateryour child has had a fever for five consecutive days or longer (under age 2 if 3 or more days)
  • your child is also showing other signs of pain or discomfort, like pain with urination, persistent headache/neck pain, bad sore throat or ear pain (note that sore throats that accompany congestion and cough are most likely viral, not strep).
  • if you are concerned about dehydration or excessive fatigue

A pediatrician’s job is to examine kids when parents are concerned.  If you are worried, please portal us. We are here to help you determine when you need to bring them in.

4. What “number” on the thermometer means an ER visit?

Over the age of two months, there is no number on a thermometer that requires a trip to the emergency department. Nope, not even 105F degrees.

It’s never wrong to seek help when you’re worried about your child, but no one wants to sit in the ER needlessly for hours. If your child gets a high temp, grab the fever reducer (see FAQ #6) and try to lower the fever at home before jumping in the car.

Pediatricians are always going to be more worried about fever for multiple days in a row (more than five) than a kiddo with a brief 105F temperature. And, we are going to be more worried about a kid who is too sleepy, not drinking or in pain — no matter the number on the thermometer.

If there has been NO change in your child’s temperature after an hour of offering a weight-based dose of medication, reach out to us for advice. (*note that high fevers may not come down fully to normal range, especially at night- if a high fever comes down a few degrees, enough that your child is more comfortable and able to sleep, there is no need to worry. If, after an hour there has been no change in the temperature you can give a different fever reducer- i.e. acetaminophen if ibuprofen was given, and vice versa)

5. Isn’t it true that fever helps the body fight infection, so we shouldn’t use fever reducer? 

The goal of offering fever reducing medication is NOT to get a high temperature back to “normal.” Fever reducers, like acetaminophen and ibuprofen, are simply medications to make your child feel better and might decrease the risk of dehydration.

As an aside, if you are coming to the pediatrician’s office because your child has a fever and her or she is uncomfortable, please give your child a fever reducing medication BEFORE coming to the office. The doctor doesn’t have to “see the fever.” We believe you. Plus, a comfortable child is much easier to examine. And a good exam will often determine the cause of the fever, allowing for accurate treatment.

6. What’s the difference between ibuprofen and acetaminophen? Which one should I use?

Fever reducers do NOT treat infection or cure a fever. The goal of these medications is to simply make your child feel better.

Acetaminphen (Tylenol) helps with pain and fever. This medication may be given to infants over the age of two months, sooner if approved by your healthcare provider. It comes in liquid, chewable, pill and rectal versions (Feverall). Acetaminophen is effective for 4-6 hours, and should not be used more than 5 times in a 24 hour period.

Ibuprofen (Advil, Motrin) helps pain, fever and swelling. Ibuprofen can be given to infants over the age of six months and is taken by mouth. Ibuprofen is effective for 6-8 hours.

Medications should be dosed according to your child’s weight, not age. If you feel that your child needs medication, give the correct dose. Weight based dosing charts are available on our website at www.saugatuckpeds.com. Learn more about safely using these meds in FAQ #7.

Fever reducer tips: 

  • It’s not uncommon during the course of an illness for the temperature to rise near the end of the dosing interval.
  • These medications may take up to an hour to start working. In the meantime you can try a tepid bath/cool cloths to help (do NOT use alcohol rubs, these can be dangerous in children.)
  • If your child has an upset stomach, choose acetaminophen.
  •  If your child has swelling, throat pain choose ibuprofen. Either medication is generally appropriate for fever and pain reduction when used in appropriate doses for acute illness. Dose fever reducers by weight, not by age.
  • Please note: Aspirin is not an option for fever reduction in children. There is link between between aspirin and a condition called Reye Syndrome. Please keep aspirin away from your childhood medications. If your child is under the care of older caregivers, like grandparents, please remind them of this concern.

7. Acetaminophen can hurt the liver, so isn’t giving ibuprofen a safer choice?

Generally speaking, fever reducing medications are considered safe if administered properly (correct age, dose, dosage device, and frequency). However, when any medication is not taken properly, intentionally or unintentionally, kids can get hurt.

Tips to decrease the risk of using medications:

  •  Medications (which many children find delicious) need to be stored in a safe place to prevent overdosing. Avoid keeping medication out on the counter or in the bedroom during times your child is ill. Always store medication in a safe place where children can’t access.
  •  Use the dosage device that came with the medication. Don’t use cereal spoons or measuring spoons from the kitchen.
  • Do not buy multi-symptom formulations, such as many cold and cough products. These products increase the risk of accidental overdose because parents may unintentionally give a fever reducer and a multi-symptom medication containing fever reducer, at the same time.


8. When my child gets a fever, I heard it’s best to alternate acetaminophen and ibuprofen. Is this true?

Although the results of a few studies have suggested fever reduction was slightly betterwhen using both medications, the risk of making a mistake while alternating fever reducers is higher than the increased relief your child may experience by using this method.

However, if your child’s fever is not coming down to a level of comfort with one medication alone, both may be used. If you choose to alternate, medication can be given every three hours. For example, acetaminophen at noon, ibuprofen at 3 pm, acetaminophen at 6 pm, etc. Make a chart to mark down the time each medication was given, and share it with all caregivers. Again, alternating two fever reducers is not needed for most illnesses.

9. Isn’t it true that a high fever causes brain damage?

Fever does not cause brain damage. Period. Full stop. Every normal brain has a internal thermostat that will prevent a person’s temperature from getting high enough to cause brain damage.

Organ damage can occur when an external factor is affecting our temperature regulation system. For example, when an individual is not able to cool oneself (as in a closed car on a summer day) or in the case of rare brain injury that has resulted in damage to the internal thermostat. A healthy child with fever is not at risk of organ damage.

10. What about febrile seizures? Don’t I have to treat fevers to prevent them?

Febrile seizures are scary to watch and terrifying for parents. But despite popular opinion, aggressive fever control does NOT prevent febrile seizures from occurring.

The cause of febrile seizure is thought to be due to a combination of genetic and environmental factors, and are the result of a developing brain’s reaction to fever. Fever reducing medications do not prevent febrile seizures from occurring. Rather, the risk of febrile seizures are associated with a child’s age at the first event and a history of family members who also had these events.

Simple febrile seizures most commonly happen in young children between 12-18 months of age. These events last for a few minutes, resolve on their own and rarely cause long-term health problems. Children grow out of these events as their brain matures, typically by elementary school.

If your child is having a unexplained or first-time seizure, call 911 for help.