Q: My 21-month-old has a high fever with no other symptoms. Could it be the flu?
- Myeongchan Kim
- May 31
- 3 min read
Medically reviewed by Sang Hyun Ahn, MD
Content edited by Myeongchan Kim, MD
This post is a dramatization of a question and answer session experienced by our actual medical reviewers. Please note that this content is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.
Question:
My 21-month-old toddler has been sick throughout December, including a hospitalization for pneumonia, sudden high fevers, and severe coughs. Last week, they were diagnosed with stomatitis. They fully recovered and went back to daycare on Wednesday.
However, today (Saturday), they had a mild fever in the morning (37.4°C - 37.9°C) and then suddenly spiked to 39.0°C after a nap. A fever reducer brought it down to 37.2°C, but 5 hours later, it rose back up to 38.4°C. They play well with a mild fever but lie down lethargically when it reaches the mid-38s. There are no other symptoms at all.
Is it possible to have the flu with only a fever? I plan to visit the clinic right when it opens tomorrow, but I am debating whether to wait until Monday because I worry about them catching another virus at the hospital. What should I do?
Answer:
It is completely understandable that you are worried, especially since your little one has been sick continuously for the past month. Dealing with recurrent illnesses is incredibly exhausting for both the child and the parents.
To answer your main question: Yes, it is entirely possible for the flu to present with only a fever. It is very common for the flu to cause sudden high fevers without accompanying respiratory symptoms like a cough or a runny nose. Young children, in particular, often show no typical symptoms other than a fever and lethargy.
Here is an assessment of your child's current situation:
Your child has a high fever (39°C) but is fortunately responding well to fever reducers.
The fluctuating fever pattern (rising and falling) is a common characteristic of the flu.
Repeated infections throughout the month mean your child's immune system is likely still recovering.
Developing a fever after returning to daycare strongly suggests a new viral infection.
I highly recommend taking your child to the pediatrician tomorrow (Sunday) rather than waiting until Monday. A rapid flu test is most accurate 12 to 24 hours after the onset of the fever, making tomorrow the optimal time for an accurate diagnosis. Additionally, clinics tend to be much more crowded on Mondays, and delaying the visit could increase the risk of complications, given your child's recent history of pneumonia and stomatitis.
How to manage the fever tonight:
Have alternating fever reducers (e.g., Acetaminophen and Ibuprofen) ready in case the fever spikes again before morning.
Offer frequent, small sips of water to prevent dehydration.
Dress your child in light, breathable clothing and keep the indoor temperature pleasantly cool.
⚠️ Emergency Warning Signs:
Please go to the nearest Emergency Room immediately if your child experiences convulsions/seizures, a loss of consciousness, difficulty breathing, or does not urinate for more than 8 hours.
While it is natural to worry about hospital-acquired infections, getting an accurate diagnosis right now is the top priority. To minimize exposure risks, keep a mask on your child if they tolerate it, practice good hand hygiene, and return home immediately after the appointment. Please consult your pediatrician tomorrow for a thorough in-person evaluation. Hang in there!
For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.
