Myths and Facts About Fevers in Children and Infants


Fever phobia. It is something I talk about on a daily basis. What is a fever? Do I need to worry, and when is it too high?

I get a lot of questions about fevers, and there are a lot of misconceptions, too, about fevers. When is it something you really need to be very concerned about, and when is it something that you can say, “Okay, this is something I can manage”?

High or Low-Grade Fever?

One of the first questions your pediatrician will ask if you come in for a cold, for a fever, or for something else that’s an illness is and you’re asked, “Did they have a fever?” And if you say, “Yes,” the first question we’re going to ask is, “How high?” A lot of people will just say, “Oh, they felt warm.”

Well, it’s really important from a doctor’s point of view that you tell us exactly what the temperature was. That tells us how concerned we should be, or if this is something we would expect with whatever you’re bringing your child in for.

So let’s discuss a couple of things about fevers to help you put this all into perspective. First, fevers are bad for children. Wrong. Fevers turn off the body’s immune system. A fever is actually a good sign that your body is working to fight off an infection. Most fevers between 100 and 104 are okay for sick kids.

When Should Babies and Infants Be Seen for Fever?

The exception is babies less than three months of age. If they have a temperature of 100.4 or higher, and that’s a rectal temperature of 100.4 or higher, they must be seen right away. That is when we really start getting worried about infections in babies that are dangerous.

What about fevers over 104? Can they cause brain damage? No. Fevers with infections don’t cause brain damage. Only body temperatures over 108 can cause brain damage. The body’s thermometer goes high, but extreme environmental temperatures, such as if a child is in a closed car in hot weather, that’s when you start worrying about the fever going high and causing brain damage.

The next concern is “What if my child has a fever? They can have a febrile seizure, which is a seizure that’s triggered a fever.” Well, the truth is only about four percent of children have febrile seizures, and while they may be scary to watch, they usually stop within five minutes, they don’t cause permanent harm, and children who have febrile seizures are not at greater risk for developmental delay, learning disabilities, or epilepsy.

Fever Treatments for Children

Do all fevers need to be treated with fever medicine? Well, only if they cause discomfort. Look to see how your child is acting. If a fever is 102 or 103, you’re going to notice that your child’s not feeling so great. They’re tired. They’re cranky. But I’ve seen kids with a fever of 101 running around in my office. So go by what your child looks like and how they’re acting rather than the number on the thermometer.

“But what if I don’t give them anything for their fever? Won’t the fever keep going higher?” No. The brain has an internal thermostat, and fevers from infection top out at about 103 and 104. They usually don’t go higher than that.

“Well, if I get them something, the fever should come down to normal.” No. Even if you treat it with Tylenol, fevers usually only come down two or three degrees, and it can take about two or three hours for the fever to come down.

“If the fever doesn’t come down, the cause has got to be something serious.” Well, no. Not necessarily. Fevers that don’t respond to fever medicine can be caused by viruses or bacteria, and, again, it doesn’t matter if the medicine works or not because you want to make sure you look at your child’s other symptoms. You can have a child with a severe virus. Bad colds. We’re seeing a lot of really nasty viruses and fevers of 103, close to 104 in the office, but these are all from viruses lately.

“Once the fever comes down, it should stay down.” Well, fevers only last two or three days with most viral illnesses. Actually, doctors don’t even start worrying until a fever has lasted for five or more days.

What Happens if a Fever Lasts Longer than Five Days?

When the medicine wears off, the fever’s going to come back because this is, again, your body’s way of trying to fight off an infection. So once your body overpowers the virus, usually by the fourth day, then the fever goes down. If it doesn’t go down, then, yes, it’s a good idea to make sure your child doesn’t have some bacterial like an infection, a urinary tract infection, or something else that would require antibiotics to treat.

“If the fever’s high, it’s got to be something serious.” Again, if your child looks very sick, the cause is more likely to be serious. It’s not important what number is on the thermometer but how your child looks.

Low-Grade Fever

A lot of parents say, “My child had a low-grade fever.” Well, what do you consider a low-grade fever? “Anywhere between 98.7 and 100.” These are actually normal variations. The body’s temperature normally changes throughout the day. It peaks in the late afternoon and evening. An actual low-grade fever is 100 to 102.

Stay Hydrated

So what about helping your child get rid of the fever? Should you let the child sweat out the fever? Do they need extra fluids? Do you need to starve a fever? What do you need to do? The best thing is to keep your child comfortable. You can remove any extra clothing and give them extra fluids because, yes, that will help them stay hydrated.

Most heat is lost through the skin, so don’t bundle up your child. Let them go ahead and sweat it out. Sometimes that is what happens because they’ll seem like they feel cold or they’re shivering, but that’s actually the fever breaking.

Medication for Fevers

Again, Tylenol and Motrin are good for fevers. Do not ever give Aspirin to a child under the age of 18. It can cause something very deadly called Reye’s syndrome, and you don’t want to give them that.

We usually say, “Don’t give your baby under 3 months old any Tylenol or Motrin unless directed by your pediatrician, for example, after vaccines.” If your child does have a fever and they’re under 10 weeks old, again, that’s something serious we need to know about.

Otherwise, your child of 3 months and up can have Tylenol. For Ibuprofen, it’s 6 months and up. Do not give Ibuprofen to a baby under 6 months old. But once they’re older than that, you can definitely give them Tylenol or Motrin.

Be sure to look because Tylenol and Motrin dosing are based on weight. So be sure you have the right dose for your child, and if you’re not sure what it is, go ahead and ask your pediatrician.

Myth: Teething Causees Fever

One more thing, teething does not cause a fever. A lot of kids around the age where they’re starting to teeth are also trying to build up their immune systems. So while they may have a fever, it’s not from teething. It’s from them trying to fight off something.

The bottom line is that fever phobia does exist, and it is something that we all worry about when our child has a fever. But the most important thing is to make sure your child is comfortable. Make sure your child looks okay.

If they look very sick no matter what the number on the temperature, be sure to bring them in. If their temperature is a little bit higher than you’re comfortable with, you’re always welcome to call and get some advice. But a fever is a good thing. It’s your body’s way of actually trying to fight off an illness. Let it do its job.

updated: May 30, 2023
originally published: May 27, 2015


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