Atypical Cogan syndrome in a child with prior immunoglobulin A vasculitis: a case report

Cogan syndrome is a rare immune-mediated disorder characterized by ocular inflammation and audiovestibular dysfunction. Pediatric cases are uncommon and often present with nonspecific systemic inflammatory symptoms, leading to diagnostic delay. We report a 12-year-old girl with acute vertigo, bilateral hearing loss, and prior iridocyclitis following a febrile illness and polyarthralgia, with a history of immunoglobulin A vasculitis (Henoch-Schönlein purpura). Neuro-otological evaluations revealed spontaneous left-beating nystagmus, positive head impulse to the right side, and bilateral sensorineural hearing loss. Extensive autoimmune, infectious, and imaging evaluations were unremarkable. Based on the coexistence of ocular inflammation and audiovestibular dysfunction, atypical Cogan syndrome was diagnosed. Audiovestibular symptoms resolved after intravenous methylprednisolone pulse therapy and subsequent treatment with oral prednisolone and methotrexate. This case highlights the diagnostic challenge of pediatric atypical Cogan syndrome and the importance of early recognition and prompt treatment.