Fevers: Fact vs. Fiction

Fevers in children seem to cause caregivers a great deal of anxiety. This stems from two factors. The first is that fevers are frequently uncomfortable. If you can remember the last time you had a fever, I’m sure you would agree. You have no energy. Your muscles ache and your head hurts. You don’t want to eat or drink anything, and you can’t sleep. This happens with children as well, and it worries caregivers to see them so miserable. The second is that there are a lot of myths surrounding fevers. This guide is designed to help you better understand the facts about fevers and when you should be concerned.

Overview

Definition

• A true fever is defined as 100.4 °F and higher.
  • This definition is important because while many things can elevate a child's temperature (e.g. teething), almost all of the true fevers in children are caused by infections (viruses or bacteria) or recent vaccination in the last three days.
  • Infections do not always cause a true fever, but you can assume every true fever is caused by an infection.
    • Common virus infections that sometimes cause fever:
      • Runny nose and cough respiratory viruses
      • Diarrhea or vomiting and diarrhea GI viruses
      • Skin rash viruses
      • Viruses do not respond to antibiotics, and the body knows how to kill these infections on its own.
    • Common bacterial infections that sometimes cause fever:
      • Ear infection
      • Pneumonia
      • Strep throat
      • Bacterial infections usually require antibiotics to kill them
• When we ask "how many days" has fever been present, we are referring to "calendar days."
  • If any fever occurred at any time from midnight to midnight, it means there was a fever on that day.
  • Fevers come and go throughout the day.

Is This a Virus Fever or Bacteria Fever?

• The vast majority of fevers are caused by viruses.
• The following fever patterns increase the possibility of bacterial infection, and should prompt you to send us a message:
  • Fever lasting three full days or more (first day is day zero).
    • Most fevers caused by viruses don't last for more than three full days.
      • The other symptoms of the virus continue.
    • If fever is present for more than three full days, we get concerned that a bacterial infection (ear infection or pneumonia) has developed on top of the original virus (usually a cold virus).
  • Fever goes away for at least 24 hours and then returns.
    • This is considered a "new fever."
    • Every new fever means a new infection.
      • Although the new fever is probably caused by a new virus, we still want to discuss the situation with you.
  • Fever is present for 48 hours and there are no other symptoms infection.
    • Sometimes 24-36 hours of fever is the only symptom we see when there's a new viral infection.
    • From there, the other virus symptoms show up
      • runny nose and cough for a cold virus
      • diarrhea with or without vomiting for a GI virus
      • skin rash
    • If your child has two full days of fever without any of these other virus symptoms, it could indicate a bacterial infection is hiding somewhere else in the body.

Fact vs. Fiction

Myth

• Fevers, especially very high ones, can permanently hurt a child. A high fever can, for example, damage the brain or other important organs.

Truth

• A fever is defined as any temperature of 100.4ºF or higher.
  • Medically speaking, there is no such thing as “mild fever” or “high fever.”
• Fever will not permanently hurt your child, regardless of how high it gets. 
• The fever just tells us there is an infection.
  • Fever is a symptom of an infection, just like cough, runny nose, or vomiting.
• What matters is that your child is not dehydrated, does not have respiratory distress, is consolable, and is not truly lethargic.

Myth

• A higher fever means the infection is more dangerous, or is more likely to be caused by a bacteria which requires antibiotics to fix.

Truth

• In children, the height of the fever does not indicate a more dangerous infection, nor does it imply a bacterial infection.
  • Common viral infections that cause a simple runny nose and cough in adults may sometimes cause fevers as high as 105ºF or 106ºF in children.
• What matters is that your child is not dehydrated, does not have respiratory distress, is consolable, and is not truly lethargic.

Myth

• The amount of acetaminophen and ibuprofen you should give for fever is based on the age of your child.

Truth

• The amount of acetaminophen or ibuprofen you should give is based on how much your child weighs.

Myth

• You should be more concerned if acetaminophen or ibuprofen don’t bring the fever down to normal, or the fever returns before the next dose is due. 

Truth

• This actually happens frequently, and does not mean the situation is more dangerous.
• What matters is that your child is not dehydrated, does not have respiratory distress, is consolable, and is not truly lethargic.

Myth

• Giving acetaminophen every 4 hours and/or ibuprofen every 6 hours (the way they are supposed to be taken) for many days in a row is not good for children.

Truth

• What matters is that the dose is correct for your child’s weight, and that you don’t give two acetaminophen doses less than 4 hours apart or two ibuprofen doses less than 6 hours apart.
• The number of days in a row is not medically important.

Myth

• As long as my child is not dehydrated, does not have respiratory distress, is not truly lethargic, and can be consoled, I don’t ever need to worry about a fever, no matter how old my child is, how long the fever has been going on, or how high the temperature gets.

Truth

• There are some fever situations you should let us know about. Whether you should let us know immediately (day or night) or during regular business hours, depends on the situation.
  • Contact Immediately, Day or Night
    • If your child is dehydrated, has respiratory distress, is inconsolable, and is truly lethargic, or if you don’t know if these things are happening.
    • If your child is less than 30 days old, and has a rectal temperature of 100.4ºF and higher, or 96.9ºF and lower.
      • In this age group the immune system is still immature, and more susceptible to dangerous, potentially life-threatening infections.
      • Although the fever is still not dangerous for these babies, and these dangerous infections are rare, you should let us know right away to make sure you don’t need to go to the emergency department.
    • Your child, regardless of age, has a fever of 105ºF or higher.
      • Although a fever of 105ºF and higher is not dangerous by itself, you should let us know right away to make sure you don’t need to go to the emergency department for dehydration, respiratory distress, inconsolability, or true lethargy.
  • Contact During Regular Business Hours
    • If a temperature of 100.4ºF has been present at some point during the day for 3 full days in a row.
      • The first time you notice a fever, we consider that day 0 of the fever.
      • The following day at the same time is 1 full day of fever.
      • If there are 3 full days of fever, you should contact the pediatrician during regular business hours to see if your child should be examined in person.
    • If your child has a fever, it goes away for at least 24 hours in a row, and then returns.
      • This could indicate that a bacterial infection (which requires antibiotics) developed on top of the original viral infection. Usually, this is just just a second, overlapping viral infection, you should let us know to determine if your child should be examined in person.