It’s 2 am. Your youngest child is upset and crying. And… they’re hot. The thermometer you have reads 102. You’re nervous. Your child is nervous. Fever can feel like your family’s worst enemy.

Believe it or not, and despite the fear often associated with it, fever is often your child’s friend.   Fever revs up the body’s immune system and activates it to fight off any viral or bacterial “invaders.”   So, when your child has a fever, it means her body is doing its job.  

Most pediatric experts agree: a fever is a temperature equal to or greater than 100.5 degrees.  That’s why when you make an appointment for your child for a “fever” we sometimes push you on the details: 100.2 you say?  Not a fever.  Felt your child and thought he was hot but didn’t take the temperature? Might have been a fever, but might not have.  We want to know, when possible, the actual temperature and how you took it (under the arm, in the mouth, in the ear, or on the skin).  Your child’s temperature depends on a number of factors, including how you take it. The closer we get to the core of the body, the more accurate it is. That’s why, when we measure the temperature of a baby, we often want to take the temperature in the baby’s bottom.  For older kids, a temperature taken in the mouth or the bottom is much more accurate than a temperature taken under the armpit.

A child’s age also matters a lot when it comes to fever.   Any child under a month of age needs to be evaluated by a doctor immediately if they have a fever, even if it only occurs once.

As kids get older and older, we are less concerned about low-grade fevers in otherwise healthy and vaccinated kids, but recommend an evaluation if your child has had a temperature for more than 2-3 days (or anytime you are concerned).  

Some things do worry us when it comes to fever. We worry when the fever lasts several days without a good explanation for it.  We worry when your child becomes dehydrated.  We worry when your child is lethargic. We worry when your child is not fully vaccinated.  Most of all, we worry about how your child “looks” overall, which is why we pay a lot of attention to this when you call or come in.  

It also doesn’t matter if the Acetaminophen or Ibuprofen you’ve been giving to treat your child’s fever makes it go away and stay away.  These medications are for your child’s comfort but don’t help to fight off the virus or bacteria your child has.  If they don’t completely eliminate the fever, it doesn’t mean they aren’t working, just that they wore off like they are supposed to.

Fever can be scary, but knowing what a fever does for the body is helpful. On average, kids will have 4 to 6 acute episodes of fever from birth to 2 years of age, so fever is here to stay, whether we like it or not. Think of it as an (often annoying, but very helpful) friend.