Treating and Measuring Fevers

Before you can treat a fever it is important to accurately measure your child’s temperature. Here are a few easy techniques to get you started.

When a child is sick, the first thing the doctor’s office may ask is, “What’s her temperature and how did you take it?” There are a variety of thermometers and ways to take a child’s temperature, so it’s helpful to know what’s recommended for each age.

Basic digital thermometers are a good choice. They are accurate, fast, easy to use, inexpensive, and can be used for a variety of temperature-taking methods: in the bottom (rectal), by mouth (oral), or under the arm. NOTE: A thermometer used for taking temperatures should not be used for other methods.

Babies under age 3 months

The rectal method is the most reliable for young infants. If your baby is under 3 months of age and has a temperature of 100.4°F or higher, contact your doctor right away. Babies this young need to be checked for infection or disease.

To take a rectal temperature:

  • Wash the thermometer, then rise with cool water
  • Coat the tip with petroleum jelly
  • Place your child either on his back with knees bent or on his belly.
  • Holding your child still, insert the thermometer ½ to 1 inch into the bottom
  • Hold until it beeps, then remove for reading

Children under age 4 years

Active, older children may not cooperate well with the rectal method. Another option is the underarm method, but it is less accurate. An underarm reading can be as much as 2 degrees lower than an internal rectal reading.

To take an underarm temperature:

  • Remove your child’s shirt
  • Make sure the underarm is dry
  • Press the thermometer tip against the armpit
  • Keep your child’s arm firmly against her side
  • Hold until it beeps, then remove for reading

Children ages 4 & up

For older kids, a temperature taken by mouth is accurate when taken properly (your child must be able to hold the thermometer in place long enough to get a reading).

To take an oral temperature:

  • Wash the thermometer, then rinse with cool water
  • Put the tip under your child’s tongue, near the back of the mouth
  • Hold in place until it beeps, then remove for reading

If you have questions or concerns, talk to your doctor.

Other ways to take your child’s temperature:

  • Ear thermometers are quick and comfortable, but can be tricky to use
  • Temporal artery thermometers are swiped across the forehead (they may be reliable, but are more expensive)
  • Fever strips and pacifier thermometers are not recommended by the American Academy of Pediatrics.

Fevers are a sign that your child's body is fighting off an infection. Most fevers are caused by common childhood illnesses like colds, flu, ear infections, bronchitis, and tonsillitis. Usually, a fever is just a symptom of an infection or other condition. In most cases, a fever will go away on its own in 2 or 3 days.


Five Symptoms to Watch For

Watch out for these symptoms in addition to fevers as they may signs of a serious– and possibly dangerous – illness. Keep an eye out for the following five symptoms, which could indicate a problem when coupled with a fever.


Lethargy. Your child has lost his appetite, has little energy, or is noticeably pale or flushed, or you notice other changes in his behavior and appearance.

Rash. Your child has small, purple-red spots on his skin that don't turn white when you press on them, or large purple blotches.

Difficulty swallowing. Your child is unable to swallow and is drooling excessively.


Difficulty breathing. Your child has difficulty breathing even after you clear his nose with a bulb syringe.

Mood. Your child seems delirious, glassy-eyed, or extremely cranky or irritable.

If you notice any of these symptoms with a fever, call your pediatrician right away.


In general, it's a good idea to check with your pediatrician if you feel uncomfortable about your child's appearance or behavior, no matter what his temperature is. Trust your gut.

Remember, too, that fever is only one sign of illness. Be sure to mention symptoms such as a cough and ear pain (if you suspect it) or vomiting and diarrhea – these can help your pediatrician make a more accurate diagnosis.

If your little one is feeling ill and you’re not completely sure what to do, don’t be afraid to pick up the phone. Sometimes it helps to get a second opinion to reassure your knowledge and instincts as a parent.


Here’s how to know if it’s time to call your child’s doctor:

For most kids, call your pediatrician if:

  • Your child is unusually fussy, sleepy, cranky, or quiet
  • Your child appears very sick
  • You are unable to lower your child's fever or your child develops other serious symptoms
  • The fever goes away for more than 24 hours and then returns
  • Your child has a fever for more than 72 hours
  • Your child is younger than 3 months with a rectal temperature above 100.1° F
  • Your child is 3 to 6 months with a rectal temperature above 101° F
  • Your child is 6 to 12 months with a rectal temperature above 103° F
  • Your child has a history of febrile seizures

Or if you notice any of these symptoms:

  • A stiff neck (unable to touch chin to chest)
  • Trouble breathing
  • Ear or sore throat pain
  • Your child has a seizure (arms and legs jerk uncontrollably)
  • Your child has a skin rash
  • Your child cries inconsolably
  • Your child is difficult to awaken

If you do call your child’s doctor, make sure to let them know which type (Infants', Children's, etc.) and strength of medicine you're giving to your child, if any. Also inform them if your child has any underlying risk factors that could cause further complications.