Q: Can my child's white blood cell count reach 20,000 due to sinusitis without a fever?
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 was recently hospitalized for five days and given antibiotics due to poor respiratory sounds, though there were no other specific symptoms. All blood and respiratory virus tests during that time were normal. On the third day after discharge, my child suddenly complained of stomach pain and vomited five times within two hours. We visited a different hospital where X-rays were taken. The abdominal X-ray was normal, but the sinus X-ray showed severe sinusitis, with the sinuses appearing completely white.
My child currently has no fever but is very lethargic. Blood sugar is normal, and the vomiting has stopped even without anti-nausea medication. However, the white blood cell (WBC) count came back at 20,000. My child was perfectly fine and eating well over the weekend, so this was very sudden. Can the WBC count rise to 20,000 just from sinusitis without a fever? Also, my child had periodic fevers for about a year, which stopped after a Mycoplasma pneumonia infection. Should I be worried about this current situation?
Answer:
It must have been very alarming to see your child suddenly start vomiting so soon after being discharged from the hospital.
Interpreting a WBC Count of 20,000:
Even without a fever, a white blood cell count can rise temporarily due to an acute bacterial infection (such as sinusitis), dehydration, physical stress, or during the recovery phase of a recent infection. If the sinus X-ray showed that the sinuses are completely filled, this indicates a likely bacterial sinusitis, which alone is enough to explain the elevated WBC count. Although your child has a history of periodic fever, the current situation should be viewed independently as a new acute infection.
What to Do at Home:
Hydration: Offer small sips of fluid frequently (one or two sips every 10 to 15 minutes) to prevent dehydration.
Diet: Once the vomiting has stopped for 4 to 6 hours, you can slowly introduce small amounts of soft, bland foods like rice porridge.
Monitor: Keep a close eye on your child's energy levels, urine output, and any signs of dry lips.
When to Seek Immediate Medical Attention:
Please take your child back to the doctor for an evaluation today if you observe any of the following warning signs:
The vomiting restarts, or the child cannot keep water down.
There is no urination for more than 8 hours, or the lips and tongue become very dry.
A fever of 38.0°C (100.4°F) or higher develops.
The child experiences a severe headache, a stiff neck, or altered consciousness/confusion.
The abdominal pain worsens, or the child shows severe pain when the stomach is gently pressed.
Regarding the History of Periodic Fever:
The fact that the periodic fevers disappeared after the Mycoplasma infection is actually a good sign. The current elevation in white blood cells is a response to a new infection. It is best to focus on managing the current sinusitis and vomiting rather than linking it to the past periodic fever.
In summary, it is entirely possible for a WBC count to reach 20,000 due to severe sinusitis, even in the absence of a fever. Since the vomiting has stopped, focus on gentle fluid replacement and watch closely for the warning signs listed above. If vomiting recurs or if you notice any signs of dehydration, please consult a pediatrician immediately for a follow-up evaluation.
For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.
