Approach to pyrexia of unknown origin in low- and middle-income countries.

Pyrexia of unknown origin (PUO) remains a significant diagnostic challenge in low- and middle-income countries (LMICs), where infections predominate despite an increasing burden of non-infectious inflammatory diseases and malignancy. Extrapulmonary tuberculosis, lymphoma, and Still's disease are among the leading causes. This article reviews the evolving epidemiology of PUO in LMICs and proposes a structured, stepwise diagnostic approach that integrates local epidemiology, potential diagnostic clues, targeted investigations, and whole-body imaging to improve diagnostic accuracy while minimising unnecessary testing.