I have a fever despite medication. What could cause it?

Question

Hello doctor,

I have been sick for a few days and have had an on-and-off fever all week. It goes away if I take Tylenol or Advil, but usually comes back in the evening or at night.

Please help.

Answer 1

Hello,

Welcome to icliniq.com.

I understand your concern.

The pattern you are describing, such as persistent fever that temporarily responds to Tylenol (Acetaminophen) or Advil (Ibuprofen) but returns in the evening, suggests there may be an underlying viral or bacterial infection that your body is still actively fighting.

Since it has been ongoing for several days, it is important to consider any accompanying symptoms such as sore throat, cough, body aches, nasal congestion, gastrointestinal issues, or rash, as these can help narrow down the cause.

Viral infections like influenza, COVID-19 (coronavirus disease of 2019), or even dengue (depending on your region) can present this way, but bacterial infections such as tonsillitis, urinary tract infections, or early pneumonia may also cause relapsing fever.

I would recommend getting a basic physical examination along with laboratory tests such as:

Complete blood count (CBC).
CRP (C-reactive protein).
A chest X-ray.
A urine test to help identify the source of the fever.

In the meantime, stay well hydrated, get adequate rest, and continue using antipyretics like Tylenol as needed.

If the fever persists beyond seven days, worsens, or if new symptoms develop, such as chills, chest pain, or difficulty breathing, please seek immediate medical evaluation to prevent complications.

I hope this helps.

For more queries, feel free to reach out to me anytime.

Thank you.