Fever: the 411


A fever is a common symptom of illness, but it not necessarily a bad thing. To the contrary, a fever is the body’s natural defense against illness and plays a key role in fighting infections. If your child is older than 6 months, is drinking plenty of fluids, sleeping well, playing normally and is not showing any signs of discomfort there is usually no need to treat with medication. Brain damage is not a concern until 108 F and is caused by environmental influences (when children are left in a hot car) not from infections.


**Please review Thermometers: Choosing a Deviceas the type of thermometer used will change with the child’s age and it is important to be using the correct type for their age/ size.


Best device based on age:

  • Babies less than 3 months
    • Rectal (not recommended for home use)
    • Armpit
      • If measuring over 99 degrees double check rectally
  • Child between 3 months and 5 years
    • Forehead
    • Ear
      • 6 months and older as the ear canal is too small in those younger than 6 months
  • Child older than 5 years
    • Mouth
    • Forehead

Your child has a temperature if he or she:

  • Has a rectal, ear (tympanic) or forehead (temporal) temperature of 100.4 F or higher.
  • Has an oral temperature of 100 F or higher.
  • Has an armpit temperature of 99 F or higher.
    • Keep in mind that this is the least accurate measurement and may need another device to confirm the results. 

What to do with the information?

  • 0-3 months:
    • Temperatures 100.4 F and over need to be seen by a medical professional ASAP.
    • Babies of this age do not have developed immune systems and a fever can become severe quickly. SEEK MEDICAL ATTENTION.
    • Do NOT give medication for fever before consulting a doctor.
  • 3-6 months:
    • Temperatures over 101 F need to contact the pediatrician.
    • Can treat with Tylenol.
  • 6 months and older:
    • Temperatures over 102 F that last longer than 48 hours and/or is not relieved with medication (reference “Acetaminophen or Ibuprofen”) need to contact the pediatrician.
    • Can treat with Tylenol and/or ibuprofen (Advil/Motrin).