What is the reason for the persistent fever of unknown origin?

Patient's question:

Fever for the 5th day today
Taking fever-reducing medicine doesn't make it burn anymore
The medicine's effect wears off, and the fever returns
Blood tests show no problems
No Mycoplasma infection

Doctor's answer:

The causes of fever in children are quite numerous. For fever, it is essential to first identify the underlying cause and then treat it accordingly. The primary methods involve drug-induced fever reduction and physical cooling methods. Specific medications should ideally be used under the guidance of a doctor.
There are many triggers that can affect a child's respiratory system. If a child is diagnosed with a respiratory condition, parents need to cooperate with the doctor to start treatment immediately, assist with gastrointestinal decompression, and develop good hygiene habits. Parents should be mindful not to let their children develop picky eating habits and should maintain a balanced diet.