Pediatric multiple sclerosis: a diagnostic overview and the importance of early identification

INTRODUCTION: Pediatric-onset multiple sclerosis (POMS) is uncommon but clinically relevant, as inflammatory demyelination occurs during brain maturation. Compared with adult-onset MS, POMS is characterized by higher early relapse rate and MRI inflammatory activity, better recovery from individual relapses, yet disability milestones are reached at a younger age. Early identification is essential to avoid treatment delays, while preventing misdiagnosis of mimics. AREAS COVERED: This review summarizes the diagnostic work-up of children with a first acquired demyelinating syndrome, differential diagnosis, the role of MRI, cerebrospinal fluid (CSF) markers, antibody testing, serum neurofilament light chain, optical pathway assessment and the 2024 McDonald criteria. Early prognostic factors and therapeutic implications are discussed, including evidence supporting early high-efficacy therapies in selected children. References for this review were identified through searches of PubMed, authors' own files, abstracts presented at main congresses, from 1 January 1979 to 1 July 2026. EXPERT OPINION: Early identification of POMS requires integrated assessment of clinical presentation, MRI lesion topography, CSF findings, antibody testing, and emerging biomarkers. Although central vein sign, paramagnetic rim lesions, kappa free light chains and serum neurofilament light chain may refine stratification, pediatric validation remains incomplete. Earlier, more accurate diagnosis should support individualized treatment to preserve long-term outcomes.