Subacute sclerosing panencephalitis (SSPE) is a rare but devastating neurological disorder caused by persistent measles virus infection. This review provides a comprehensive overview of SSPE, focusing on its epidemiology, clinical presentation, and diagnostic challenges. Primarily affecting children and young adults, SSPE presents with diverse and often atypical symptoms, making diagnosis difficult. This review synthesizes recent research to highlight the importance of a thorough clinical evaluation, incorporating detailed history, physical examination, neuroimaging, electroencephalography (EEG), and cerebrospinal fluid (CSF) analysis, to ensure timely and accurate diagnosis. Early recognition and intervention are crucial to improve outcomes for individuals affected by this debilitating disease.