Q: My 7-month-old baby has a fluctuating high fever up to 39.8°C for a week despite antibiotics. Should we get blood tests?
- Myeongchan Kim, MD
- 4 minutes ago
- 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 7-month-old baby has a cold with a runny nose, cough, and fever. We've visited the doctor twice, and both times they said the chest sounds were clear and the throat wasn't swollen. The baby is currently taking antibiotics for the symptoms.
The fever started about a week ago. For the first three days, I gave acetaminophen 1-2 times a day to bring it down. On the fifth day around 7 PM, the fever suddenly spiked to 39.6°C, so I gave another dose of fever reducer. Yesterday, the baby's temperature was normal all day, but today at 2 AM, it suddenly spiked again to 39.8°C.
Is this normal? What could be causing this, and should we get a blood test? I wondered if it might be a urinary tract infection (UTI), but the urine doesn't smell. I also doubt it's pneumonia because the fever drops easily with medication and the cough isn't too severe.
Answer:
It is completely understandable to be worried when your 7-month-old baby has a fluctuating fever for a week, especially when it spikes to 39.8°C in the middle of the night.
To summarize the current situation, your baby has had a fever for about seven days, accompanied by a runny nose, phlegm, and a cough. Despite taking antibiotics and having previously normal chest and throat exams, the fever continues to drop and then spike again.
When to visit the Emergency Room immediately:
Please go to the ER right away if your baby shows any of these signs:
Difficulty breathing or chest retractions (the skin pulling in around the ribs with each breath)
Severe lethargy or unresponsiveness
Refusal to drink fluids
No wet diapers for over 8 hours
You need to see a pediatrician for a re-evaluation today.
The current symptom pattern differs from a standard cold. Recurring high fevers despite taking antibiotics, a fever lasting 7 days or more, and sudden fever spikes after a period of normal temperature all indicate that further investigation is needed.
Possible causes your doctor may consider:
Secondary bacterial infections (such as an ear infection or sinus infection)
Co-infection with another virus
The current bacteria is resistant to the prescribed antibiotics, or it's a different strain
Urinary Tract Infection (UTI) - Please note that UTIs in infants can absolutely occur without any noticeable or foul smell in the urine.
What to check at the clinic:
An ear re-examination (ear infections can often develop a few days into a respiratory illness)
A blood test to check inflammation markers and white blood cell counts
A urine test to rule out a UTI
A repeat chest examination to listen to the lungs
Home care management:
Alternate antipyretics (acetaminophen and ibuprofen) to manage high fevers, as directed by your doctor.
Offer frequent hydration (small, frequent amounts of breastmilk, formula, or water).
Use a humidifier and apply saline nasal drops to help clear congestion.
A fever lasting over 7 days combined with a lack of response to the current antibiotics means that additional testing is necessary to pinpoint the exact cause. Please make sure to visit your pediatrician for an in-person evaluation today.
For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.
