Q: Why does my child's fever keep going up and down over the past two days without other cold symptoms?
- Myeongchan Kim, MD
- 12 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 child's fever is going up and down, and I am very worried. Starting early in the morning two days ago, my child had a high fever (38-39°C). It went down slightly after taking acetaminophen. Yesterday, the fever didn't completely resolve, so I gave dexibuprofen before bedtime, and their temperature returned to a normal 36.6°C. My child slept well through the night, but this morning they felt hot again, and the thermometer showed a high fever of 38°C.
Why does a fever drop and then come back like this? There is no active cough or runny nose, but my child recently had a phlegmy cough, and occasionally their voice gets hoarse due to residual phlegm. Please advise!
Answer:
It is completely understandable that you are worried about your child's fluctuating fever over the past two days.
Here is a quick summary of your child's current situation:
High fever (38–39°C) started two days ago and temporarily improved with fever reducers.
The temperature dropped to normal (36.6°C) last night after taking dexibuprofen, but spiked back to 38°C this morning.
No active cough or runny nose, just occasional hoarseness from a previous respiratory infection.
Why the Fever Fluctuates
During the first 2 to 3 days of a viral infection, it is a very natural progression for a fever to rise again once the fever-reducing medication wears off. While the body is actively fighting off the virus, the brain's temperature control center is set to a higher baseline. Therefore, as soon as the medication's effect diminishes, the fever naturally returns.
What You Can Do at Home
Hydration: Offer small, frequent sips of water or electrolyte beverages to prevent dehydration.
Comfortable Environment: Dress your child in light, breathable clothing and maintain a comfortable room temperature (avoid wiping them down with wet towels or giving tepid baths, as this is no longer recommended).
Medication: Use fever-reducing medications only when your child is visibly uncomfortable. Focus on their overall behavior and comfort level rather than just the number on the thermometer.
Observation: Keep a close eye on their urine frequency and color, as well as their appetite and willingness to play.
When to See a Doctor Today
Seek immediate evaluation at a pediatrician's office or urgent care if you notice any of the following warning signs:
Difficulty breathing (e.g., chest retractions where the skin pulls in under the ribs, nasal flaring, or wheezing).
Signs of severe dehydration (no urine for more than 8 hours, or a very dry mouth, lips, and tongue).
Extreme lethargy or an inability to make eye contact.
The fever persists for more than 3 days (72 hours) or steadily worsens.
Your child complains of pain in the throat, ears, or abdomen, or develops a new rash.
Start by focusing on careful observation and keeping your child well-hydrated today. Please consult your regular pediatrician or visit an urgent care clinic immediately if your child's condition worsens or if any of the warning signs mentioned above appear.
For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.
