Extrapulmonary Systemic Manifestations in Pediatric Mycoplasma pneumoniae Infection

BACKGROUND: Extrapulmonary manifestations of Mycoplasma pneumoniae infection affect multiple organ systems in children, but comprehensive data outside hospitalized settings remain limited. We assessed the frequency and clinical characteristics of extrapulmonary manifestations in children with M. pneumoniae infection. METHODS: In this single-center retrospective study, we reviewed records of children younger than 18 years diagnosed with M. pneumoniae infection at Denizli State Hospital between January 2024 and March 2026. Demographic, clinical, laboratory and treatment data were analyzed; patients with co-infection, underlying disease or incomplete data were excluded. RESULTS: Of 348 children with M. pneumoniae infection, 206 (59%) had extrapulmonary involvement; after exclusions, 144 (41%) with acute infection-related extrapulmonary manifestations were analyzed (median age, 9.4 years; male-to-female ratio, 1.25). Approximately 12% required hospitalization. Dermatologic involvement was the most common finding (34%), followed by gastrointestinal/hepatic (13.2%), renal (8.3%), musculoskeletal (7%), hematologic (6.9%) and neurologic (3.5%) involvement. Dermatologic manifestations were more frequent in children younger than 5 years, whereas renal, musculoskeletal and neurologic involvement predominated in those older than 12 years. Age and C-reactive protein levels were associated with specific manifestation types on univariate analysis, but these associations were not retained on multivariate analysis. All patients recovered without sequelae or death. CONCLUSIONS: Extrapulmonary manifestations occurred in a substantial proportion of children with M. pneumoniae infection and involved multiple organ systems, most commonly the skin. Mycoplasma pneumoniae infection should not be regarded as a disease limited to the respiratory tract and should be considered in children presenting with rash or unexplained multisystem involvement.