Fever: How High Is Too High?

I just finished 7 straight days of being “on call.” By far, the number one question I got from parents was, “My child has a fever of ….(fill in any number)….should I be worried and take them to the ER?” Their follow up question was always, “How high is too high for a fever?” This is a completely understandable worry. Parents just want to make sure that they are always doing best by their children, especially when they are sick.

What temperature constitutes a fever?

The official cut off for fever is 100.4 F or 38 C.

So… How high is too high?

The short answer is 105. However, there is always more to the explanation. Be worried about a lower number (101-103) if your child looks terrible, I mean REALLY terrible. A sick kid with a fever will be hot to the touch and feel generally miserable, but a child that is listless (limp), having trouble breathing, or is dehydrated is another story. Those kids need to seek urgent medical care.

Infants: The exception to the rule.

All infants under 2 months of age who have any fever greater than 100.4 F (or 38 C) (rectal temperature) need to be seen by a medical professional.

Should I go to the ER with fever?

The short answer is maybe. Different factors play into the answer.

Age. An older child with a fever and cold-like symptoms can likely be treated at home.

Duration. A fever that has been going on for more than 5 days, needs to be seen by a doctor.

Infants. Again, anyone less than 2 months should be seen by a doctor.

Time of day. Generally, fever concerns can be handled by your doctor in the office (skip the expense and waiting of the ER) during the day.

Recurrent. If the fever happens initially with an illness, goes away for a few days, then comes back, you should seek medical care. A fever that returns can be a sign of a complication (e.g., a cold that has developed an ear infection or pneumonia).

Other symptoms. Fever plus certain other symptoms change the level of concern. Fever and one other very focal painful symptom usually warrants being seen without delay (examples: fever + sore throat may be strep throat; fever + painful urination may be a urinary tract infection; fever + right lower abdominal pain may equal  appendicitis; fever + ear pain may be an ear infection). Fever and many other mild symptoms (e.g., cough, runny nose, body aches) generally indicate viruses and can often be handled at home.

I gave Tylenol/Motrin and the fever won’t break.

The goal in treating a fever with Tylenol or Motrin is to make a child feel better. It isn’t necessarily a more “worrisome” sign that the fever didn’t “break” (that is, drop below 100.4) with the medication. The medication isn’t a cure, it’s a symptom reliever. Don’t worry too much if the fever doesn’t go away completely. More concerning is always the question: “How does your child look?”

Good luck!

I hope this helps you navigate what to do when your child has a fever. You might also want to look at my article, “Should I Worry About Fever?”