February 11, 2026

Fever in a child often worries parents. The good news is that fever is common and often part of the body’s normal response to illness. Let’s walk through what fever means and how you can care for your child with confidence.

What is a fever?

A fever is a higher-than-normal body temperature. Most people have a body temperature around 98.6°F. Some children can be a little higher or lower. Health care experts call it a fever when it is higher than 100.4°F.

Fever is usually caused by a virus, like the flu. It can also be caused by bacteria, like from an ear infection. A fever is a sign that the body is fighting off germs. The fever itself is not an illness.

What thermometer should I use?

The American Academy of Pediatrics recommends the use of digital thermometers. These can be placed in the rectum, mouth, or armpit.  Glass thermometers are no longer used because they can break and release mercury, which can cause harm. And, ear and forehead thermometers are newer, but not always accurate.

For babies under 3 months:

You must use a rectal thermometer. Call your child’s primary pediatric provider or Imagine Pediatrics or go to the emergency department right away for any rectal temperature of 100.4°F or higher.

For children 3 months to 3 years:

Rectal temperatures are still best, but you can start by checking under your child’s arm. Always report the number you see, do not add degrees.

For children 4 years and older:

You can start checking temperatures by mouth, under the tongue, with lips closed.

How do I take my child’s temperature?

Rectal temperature (most accurate for infants)

• Turn on the digital thermometer.
• Put a small amount of lubricant such as petroleum jelly on the tip of the thermometer.
• Lay your baby on your lap or on a firm, safe surface.
• Gently insert the tip into your baby’s rectum about ½ inches deep.
• Hold it in place until it beeps or for about one minute.
• Read and record the temperature.

Do not use this thermometer to check any other type of temperature. Use a different thermometer for mouth and armpit temperatures.

Oral temperature (4 years and older)

• Turn on the thermometer.
• Place the tip under your child’s tongue on one side in the back of the mouth.
• Ask your child to close their lips and breathe through their nose.
• Hold in place until it beeps or for about one minute.
• Read and record the temperature.

Armpit temperature

• Turn on the thermometer.
• Place the tip of the thermometer in your child’s armpit.
• Hold until it beeps or for about one minute.
• Read and record the temperature

Do not add degrees. If the reading is 99°F or higher, your primary care team or Imagine Pediatrics care team member may ask you to recheck it rectally or by mouth.

Is fever dangerous?

Fever can be scary, but it isn’t always a bad thing. It is a sign that your child’s immune system is fighting germs. Children often feel uncomfortable with a fever, which can bring chills, faster breathing, headache, upset stomach, or poor appetite. These are the symptoms we treat when health care experts recommend fever reducers.

When should I worry?

Call your primary pediatric provider or Imagine Pediatrics care team or go to the emergency department right away if:

• Your baby under 3 months has a rectal temperature of 100.4°F or higher.
• Your child has a fever of 104°F or higher.
• Your child has a seizure with a fever.
• Your child uses medical equipment or has a weak immune system.
• You notice changes in your child’s breathing, color, or alertness.

How can I treat my child’s fever at home?

Most fevers can be treated at home. At Imagine Pediatrics, we work with your child’s primary pediatric provider or specialist to follow their care plan.

Fever can be treated with:

• Acetaminophen (also known as Tylenol)
• Ibuprofen (also known as Motrin or Advil) for children 6 months and older
• Light clothing
• Cool washcloths
• Lukewarm baths

If your child has a chronic condition, talk with their primary pediatric provider first or schedule a visit with an Imagine Pediatrics clinical team member before giving your child medicine for their fever. Imagine Pediatrics can also help by coordinating with your care team. For more support, our Mobile Integrated Care team can come to your home to check ears, listen to lungs, do swab tests, and give medicine when needed.

Fevers are common, and most children recover well. If you have questions or concerns, Imagine Pediatrics is here to support you and your family. Our goal is to help your child have more safe days at home.