Frequently asked questions about fever

When should I give my child medicine for a fever?

Children with temperatures less than 102 degrees Fahrenheit only require medication if they are uncomfortable.  

What medicine should I give, and how much?

Click here to see a dosage chart for Tylenol (acetaminophen) and Motrin (ibuprofen)

How frequently can I give medicine for fever?

Tylenol (acetaminophen) can be given every 4 hours.  Motrin (ibuprofen) can be given every 6 – 8 hours.  The time interval between successive doses of Tylenol or successive doses of Motrin is what matters; it can be less time than the recommended intervals if alternating Tylenol and Motrin (e.g. you can give Motrin 3 hours after giving Tylenol).  However, we generally do not advocate alternating medications unless your doctor tells you to do so.

When is a fever a sign of a serious illness?

This depends on the age of your child.  As your doctors, we want to know about all infants less than 3 months of age with a rectal temperature of 100.5 degrees Fahrenheit or greater.

For toddlers and older children, consider the child’s behavior and activity level as well as the degree of the fever when assessing the severity of the illness.  The following signs are generally reassuring that the illness is not serious:
  • Wanting to play
  • Eating and drinking well
  • Alert, smiling at you
  • Appears well (happy, comfortable, active) when the temperature comes down (e.g. after administering a fever-reducing medication)
  • Normal skin color

Does teething cause fever?

Teething rarely causes a baby or toddler’s temperature to be greater than 100 degrees Fahrenheit.

What kind of thermometer should I have (e.g. rectal, oral, under arm, ear, forehead)?

Rectal thermometers are most accurate in infants and children until they are able to take oral temperatures.

Axillary thermometers are often digital thermometers that can be used orally, rectally or axillary.  In a cooperative infant or child who can be held still, this form of the temperature is less accurate then rectal or oral; however, in an uncooperative child, axillary temperatures may be a good first option.  If the temperature is elevated, though, an oral or rectal temperature should then be measured.

Other methods: Ear, forehead, pacifier thermometers are all to be considered generally unreliable.
Ear thermometers measure the temperature inside a child’s ear canal.  The American Academy of Pediatrics advises against the use of these thermometers in infants less than 3 months of age.  These thermometers may not be reliable in younger children because of the smaller size of their ear canals and thus may underestimate or overestimate the temperature in those children.  Forehead thermometers are plastic strips pressed against your child’s forehead.  They are not reliable in infants or children, and we do not recommend them. Pacifier thermometers, like ear thermometers, should not be used in infants less than 3 months of age.  They are unreliable and require the pacifier be held in the mouth for several minutes, without moving, which can be very difficult in infants and toddlers, especially those who are not feeling well.

Mercury thermometers are not recommended due to the possible exposure to mercury, an environmental toxin.

How do I safely take a rectal temperature?

Until children can take oral temperature, rectal temperatures are the most accurate way of knowing what your child’s temperature.
(1)Lubricate the tip of the thermometer with a water-soluble jelly (e.g. vaseline).
(2)Lay your child on a firm, flat surface.
(3)Hold your child firmly to hold him/her still.
(4)Insert the thermometer into the anal opening about a half an inch to one inch into the rectum.  Stop if you feel any resistance.

Do liquids affect oral temperatures?

Yes, you should wait 20 – 30 minutes after your child finishes eating or drinking to take an oral temperature.



Please call us with any questions
Call us at (301) 625-2800

Silver Spring Pediatrics
Drs. DeConcini, Schooler, Zang, Wang, Yee & Marcus
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