Fevers in Children: When to Worry and When to Stay Calm

This article was originally published in 2022 and last updated in October 2025 for relevance.

Do we need to be worried when our kids spike a low- or high-grade fever? Dr. Saima Jafri, pediatrician with Connecticut Children’s Care Network, lays out the facts on fever in kids.

What you'll learn:

Fever is often the body’s natural defense, not always alarming
The actual temperature is less important than accompanying signs
Most fevers don’t need medication
High fevers rarely cause brain damage
Know when to seek immediate medical attention

1. Is fever in babies and kids a good or bad thing?

It may not feel this way, but fever is a good thing. Fever is the body’s way of fighting an infection and “killing the germ.”

When your child’s temperature rises above 100.4 degrees Fahreinheit, it’s a fever, which means their immune system is working the way it should.

(There are a few exceptions—so keep reading…)

While fever is caused by an infection, sometimes your child may have a fever with no other symptoms at all. Please don’t panic—this is common—especially after vaccinations or certain procedures that involve anesthesia. Always ask your pediatrician if you’re unsure.

2. Does the exact temperature of a fever matter?

Not usually. The temperature of the fever doesn’t tell the fully story of how sick your child is.

Temperatures range for many different reasons—some viruses cause higher fevers than others. It’s also helpful to know that fevers usually spike at night because there is less cortisol in the blood which means the white blood cells are on “high alert” and detect infection more easily.

3. Will a 104-degree fever cause brain damage if I don't medicate?

No, they won’t burn up and their brains won’t fry (see below) if you decide to let the fever “break” or run its course without giving medication.

I’ve seen children run around with 104-degree fevers, and children on the sleepier side with low-grade, 100-degree fevers. If a child looks or feels uncomfortable, by all means, please give them the appropriate dose of acetaminophen (Tylenol) or ibuprofen (Motrin). Your pediatrician will tell you the exact dosage for their weight and age.

4. Do high fevers cause seizures?

Febrile seizures can happen when a child’s body temperature increases quickly.

This has nothing to do with the temperature itself. These seizures can be scary to watch, but they are harmless and only last a few minutes. And, no, febrile seizures do not damage a child’s brain.

5. Does teething cause fevers?

According to the American Academy of Pediatrics, there is no scientific evidence that teething causes fevers.

If your child is popping their first set of teeth, or many at once, it’s possible to have an elevated body temperature of 100 or lower because of inflammation, but not a full-blown fever.

So, why does it seem like every time a tooth emerges, your child gets a high fever? Teething hurts the mouth, and when that happens, children suck and chew on their hands and fingers to self-soothe. Then, germs enter and those germs put a virus into your child’s body, which causes the fever.

6. How high is too high for a fever and when should you get immediate medical attention?

If your child:

Is 3 months or younger and has a rectal temperature of 100.4 or higher, call the pediatrician right away and do not give medication unless your doctor has told you to. Fever in newborns isn’t typical, which is why you need to call the doctor.
Is running a temperature of 102 or higher and it lasts more than two days, visit the emergency room to rule out any bacterial infections.

Post this list somewhere in your kitchen, if helpful.

It’s never easy to see our children sick or in discomfort. I always tell parents to look at the whole child and not just the fever. Trust your gut—you know best.