Q: My 42-month-old has a persistent 40°C fever that won't respond to medication. Should we get a flu test?
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 42-month-old child has had a fever of 39-40°C (102.2-104°F) since Monday. We visited the doctor yesterday, and a chest X-ray showed no signs of pneumonia. They administered a fever-reducing injection and advised us to get a flu test if the fever persists. My child is barely eating, the fever won't go down despite taking fever-reducing medications, and they are having a really hard time. Should we proceed with the flu test?
Answer:
It is completely understandable that you are worried, especially since your child has been struggling with a high fever for three days.
Current Situation Summary:
Persistent high fever of 39-40°C (102.2-104°F) since Monday (Day 3).
Chest X-ray is normal, and a fever-reducing injection was given, but the fever remains.
Decreased appetite and struggling through the night.
No mention of breathing difficulties, cyanosis (bluish skin/lips), or altered mental status.
Flu Test Recommendation:
Yes, you should strongly consider visiting the clinic again today for a flu test, especially if any of the following apply:
The fever persists for 3 or more days despite taking fever reducers.
The child is having difficulty eating or drinking fluids.
Urine output has decreased (e.g., no wet diaper for 8 hours or more).
The child is significantly more lethargic or less responsive than usual.
Note: If diagnosed with the flu, antiviral medications (like Tamiflu) are most effective when started within 48 hours of symptom onset. However, even on day 3, a doctor may still prescribe them if the symptoms are severe or based on clinical judgment.
What to Do at Home Now:
Fever Reducers: Double-check the medication dosage based on your child's current weight (Acetaminophen: 10–15 mg/kg per dose; Ibuprofen: 5–10 mg/kg per dose).
Hydration: Offer small amounts of fluids (water, oral rehydration solutions, or clear broth) frequently, about every 5–10 minutes.
Comfort: Dress your child in light, breathable clothing and keep the room at a comfortably cool temperature.
Monitor: Keep track of the frequency and color of their urine to ensure they are not dehydrated.
When to Go to the Emergency Room Immediately:
Seek immediate emergency medical care if you notice any of the following danger signs:
Difficulty breathing (e.g., chest retractions where the skin pulls in around the ribs, or nasal flaring).
Bluish or pale discoloration of the lips, tongue, or fingernails.
Difficulty waking up, extreme lethargy, or lack of response.
No urination for more than 8 hours.
Next Steps:
Please contact your pediatrician's office today to arrange a flu test and update them on your child's fever, fluid intake, and urine output. If it is after regular hours or a holiday, please visit a local urgent care center or pediatric emergency room for an in-person evaluation.
For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.
