Fever in Children: What Parents Need to Know

A fever is a temperature of 100.4°F (38°C) or higher. Most fevers in children are the body's natural way of fighting an infection and are not harmful on their own. How your child looks and acts matters more than the number on the thermometer. The big exception is babies under 3 months: any fever of 100.4°F or higher needs a call to your pediatrician right away.

Few things worry parents more than a hot forehead at 2 a.m. As pediatricians who have cared for families in Princeton and across Mercer and Somerset counties for decades, we answer fever questions every single day. This guide covers what we want every parent to know: what counts as a fever, why it happens, how to help your child feel better, and when it's time to call us or head to the emergency room.

What temperature is considered a fever in a child?

A temperature of 100.4°F (38°C) or higher, taken rectally, on the forehead, or in the ear, is a fever. The cutoff is slightly lower for other methods because they read cooler..

A few tips for an accurate reading: wait about 15 minutes after a bath or a warm drink, and don't rely on how your child's forehead feels to the touch. If you call us, tell us the number, the method you used, and whether you'd given any fever medicine beforehand.

Is a fever bad for my child?

In most cases, no. A fever is usually a sign that your child's immune system is working exactly as it should.

When germs get into the body, the brain raises the body's "thermostat" on purpose. That higher temperature makes it harder for many viruses and bacteria to multiply, and it helps the immune system respond faster. In other words, the fever isn't the illness. It's part of the body's defense against it.

Most childhood fevers come from common viral infections like colds, the flu, and stomach bugs. These usually run their course in two to three days.

Many parents worry that a high fever can cause brain damage. Fevers caused by infection almost never climb high enough to do that. A child with a 104°F fever who is playing and drinking well is often less concerning to us than a child with a 101°F fever who is limp and hard to wake.



Some young children, usually between 6 months and 5 years old, have a brief seizure when their temperature rises quickly. These febrile seizures are frightening to watch but rarely cause lasting harm. Any seizure still needs prompt medical attention (see the ER section below).

How can I keep my child comfortable during a fever?

The goal of fever care is to help your child feel better, not to force the thermometer back to normal.

• Offer plenty of fluids. Water, breast milk or formula, diluted juice, broth, and ice pops all count. Fever makes children lose fluid faster than usual.
• Dress them lightly. One light layer and a thin blanket are enough. Bundling up traps heat, even if your child has chills.
• Keep the room comfortable. A normal room temperature, not hot or cold, works best.
• Encourage rest, not bed rest. Quiet play is fine if your child feels up to it.
• Let them sleep. There's no need to wake a sleeping child just to give fever medicine.
• Skip the cold baths. Ice baths, cold water, and rubbing alcohol can cause shivering, which raises body temperature. Rubbing alcohol can also be absorbed through the skin and is unsafe.

Don't worry if your child's appetite drops for a day or two. Fluids matter much more than food while they're sick..

How much fever medicine should I give my child?

The right dose of fever medicine depends on your child's weight, not their age. Always check with our office or our Medicine Dosages page before giving a dose.

Acetaminophen (Tylenol) and ibuprofen (Motrin, Advil) can both ease fever and aches. But using them safely takes a little care:



• Dose by weight. Two children the same age can need very different doses. Weigh your child if you're unsure, and use their current weight.
• Use the measuring tool that comes with the medicine. Kitchen spoons aren't accurate. Liquid medicines also come in different strengths, so read the label every time.
• Watch the age limits. Never give any fever medicine to a baby under 3 months without talking to us first. Ibuprofen is only for babies 6 months and older.
• Never give aspirin to children or teens. It's linked to Reye's syndrome, a rare but serious illness.
• Check for hidden doubles. Many cold and flu products already contain acetaminophen or ibuprofen. Giving them together with a fever reducer can lead to an accidental overdose.

Not sure about the dose? Call us. We'd much rather answer a quick dosing question than have you guess.

When should I call the pediatrician about a fever?

Call us right away, day or night, if your baby is under 3 months old and has a temperature of 100.4°F (38°C) or higher. Young babies can become seriously ill quickly, so they always need to be checked.

For older children, call our office if your child:

• Has a fever that lasts more than 24 hours and is under 2 years old
• Has a fever that lasts more than 3 days at any age
• Has a fever of 104°F (40°C) or higher
• Has a fever that went away for a day or more and then came back
• Shows signs of mild dehydration, such as fewer wet diapers, dark urine, or a dry mouth
• Complains of ear pain, a sore throat, pain when peeing, or a new rash
• Seems sicker than you'd expect, or is still very fussy after fever medicine takes effect
• Has a chronic health condition or a weakened immune system
• Just doesn't seem right to you. You know your child best.

How to reach us: Call 609-924-4892. Our Direct-to-Doctor Phone Hour runs 365 days a year, and we offer in-office appointments for sick children seven mornings a week. For help outside office hours, see the After Hours page on our website.

When should I take my child to the ER for a fever?

Go to the nearest emergency room or call 911 if your child has a fever along with any of these warning signs:

• Trouble breathing, fast or labored breathing, or lips or skin that look blue or gray
• Very hard to wake, unusually limp, or not responding normally
• A seizure, especially one lasting longer than 5 minutes, or a first-ever seizure
• A stiff neck, a severe headache, or confusion
• Purple or red spots on the skin that don't fade when you press on them
• Signs of severe dehydration, such as no urine in 8 hours, no tears when crying, or a sunken soft spot in a baby
• Crying that can't be soothed for hours, or crying when moved or touched

If you're unsure whether it's an emergency, call 911. It's always better to be safe. Our Emergencies page has more guidance on urgent situations.

We're here when fever strikes

Fevers are a normal part of childhood, but you never have to manage one alone.

Whether you need a quick dosing answer or a same-day sick visit, The Pediatric Group is here for your family. Call us at 609-924-4892 or visit us at 281 Witherspoon Street, Suite 200, Princeton, NJ 08540.

This article is for general education and isn't a substitute for medical advice for your child. If you're worried, please call us.