I get questions about fever all the time when I am talking to patients and parents. There are lots of viruses and some bacteria that fly around at all times of the year and cause kids to run fever.  Parents always want to know: 1. How high is too high? 2. When do we need to go to the ER? 3. When should we treat with Tylenol and ibuprofen? How often should we give those medicines?

Here are the most important things about fever that I want families to know, from a Pediatrician’s perspective. I hope that it will help you feel empowered to help your child through their next febrile illness, and that you’ll learn some fun facts along the way.

 

1. Fever has a job.

Our bodies are designed to work for us and keep us upright. 99% of the time, when a child is running a fever, that is their body’s way of working to try to kill whatever virus or bacteria has caused them to be sick. The idea is that certain viruses and bacteria thrive at our body’s natural temp of around 97-99. When the body elevates its temperature, using molecules sent out by the immune system, it makes those viruses and bacteria less comfortable and less able to “thrive.”  Fever is not the enemy here. The virus or bacteria is the enemy that we are working to get rid of.

 

2. How old is your child?

If you have a newborn that is less than 1 month old and has fever of 100.4 or higher (taken rectally, because yes this really is the most accurate measure of body temperature in a baby and accuracy is important in this scenario), then you need to go ahead and go to the ER – preferably a children’s hospital ER if you are close to one. The reason for this is that infants less than one month old are more vulnerable to bacterial infection, so we want to check some labs to assess for signs of bacterial infection. If your child is 1-3 months old, schedule an appointment with your pediatrician or PCP for evaluation because we do like to take a look at baby’s this age who have a fever. If your child is older than 3 months, keep them drinking and watch their symptoms (see below). You can always call your doctor for advice and for help deciding if and when they need to be seen (that’s what we’re here for!).

 

3. How does your child look?

 When people ask if they should treat their kid’s fever, my next response is always to take a look at your child. Are they sitting in front of you playing with a toy, toddling around the room, or napping comfortably? If the answer is yes, then the number on the thermometer really doesn’t matter. You don’t need to give medicine to treat a number. Because again, the fever is doing a job. However, if your child is crying, very fussy, complaining of a headache/sore throat, refusing to drink, or just generally looks totally miserable – go ahead and treat with Tylenol or motrin. ** There is an exception to this rule, see the end of this post**

 

4. Keep them drinking.

When kids run fever for a few days, they lose more of their body’s water through what we call insensible losses (sweating, breathing a bit faster, etc). The most important thing to do is to keep your kid drinking all throughout the day. If your child is less than 6 months, offer breastfeeding, a bottle of breatmilk, or bottle of formula no less than every 2 hours during the day. If your child is 6 months to 1 year, offer regular bottles or breastfeeding sessions and then offer a bottle or sippy cup with 1-2 oz of water in between each feed. If your child is over 1 year, offer a sippy cup or bottle of water about every hour. Toddlers especially are stubborn and you have to be very persistent (borderline annoying) with how often you offer them a drink. Avoid juice, tea, and soda, as too much sugar during an illness can cause you more problems. Gatorade is ok, but still a little more sugar than ideal. Mixing Gatorade half and half with water is a decent substitute for Pedialyte. If your child goes 2-3 days where they don’t eat much of anything, I don’t stress too much about that, as long as they keep drinking. Their appetite will return once their body has fought off whatever illness is plaguing them.

 

5. The 5 day rule.

If your child has been running a fever of 100.4 or higher for more than 5 days in a row, bring them in to get checked out. The majority of viruses that cause a kid to run fever will improve on their own after the first 4 days, although the flu can unfortunately cause high fever for 7-10 days in the worst case scenario. However, no matter what the symptoms or presumed diagnosis, after 5 days of fever, I always recommend that the kids come in for a recheck. We want to look at their hydration status, make sure there is no ear infection, or any other signs of bacterial infection or inflammation that may need to be treated. 

 

6. How high is too high?

There is no specific number at which I recommend families go to the ER. You do not need to take your child to the ER or urgent care for a fever of 103.8 if they are able to hold down fluids and are breathing comfortably. Here are the reasons that I recommend that families take the child to the ER with a fever: a) infant less than 1 month as described above b) your child is breathing fast and hard, seems to be having a hard time catching their breath or using a lot of muscles to try to breath c) is recurrently vomiting or is refusing to drink any liquids d) has had a significant decrease in the number of wet diapers in a 24 hour period, e) is in a lot of pain that is not improved with Tylenol or motrin, or f) has fever of 104 that does not respond at all to weight appropriate dose of Tylenol or motrin. If you are unsure if you need to head to the ER, call your doc, because again, that is what I am here for!

 

7. How much medicine do we give and how often?

See above on whether or not you need to actually give medicine for the fever. If treatment is indicated: for a child less than 6 months old, you can give Tylenol (infants or children’s, as they are the exact same medication in different packaging). Tylenol can be given every 4-6 hours. The dose depends on your child’s weight. When I do baby check-ups, I try to always remember to give the parents the child’s most up to date Tylenol dosage based on their weight at the visit. If you haven’t received that information, you can use the dosing guide on the package. If your child is 6 months or older, you can give either Tylenol or ibuprofen. Ibuprofen (which is also known a Motrin or Advil) can be given every 6-8 hours. The dose is also weight based. Infant’s motrin comes in concentrated drop form and children’s motrin comes in a less concentrated liquid form. I prefer that parent’s get the children’s motrin, as it’s harder to accidentally overdose. Tylenol and ibuprofen both help bring down a child’s temperature when they have a fever. Ibuprofen helps a little more with aches and pains. If your child is running a persistent high fever and is miserable, you can alternate the medications every 3 hours. For example, you could give a dose of Tylenol at 7am, dose of ibuprofen at 10am, dose of Tylenol at 1pm, dose of ibuprofen at 4pm, etc. However, I only recommend doing that if a kid is having a high fever and misery and we need to get them a little bit more comfortable so that they can drink and rest.

 

** The exception to the rule on treating fever: If your child has had a febrile seizure in the past and they start to run a fever of 100.4 or higher, we do recommend that you start treating with Tylenol or ibuprofen. The reason for this is that children who have had a febrile seizure in the past are a bit more likely to have another one with fever in the future, and we would like to avoid another seizure if possible. We will talk more about febrile seizures in a future blog post**

Resources:

healthychildren.org