Successful Long-Term Treatment of Pediatric Relapsing Idiopathic Optic Neuritis with Mycophenolate Mofetil.

Pediatric optic neuritis (ON) is a rare but severe condition characterized by acute visual impairment, with 3-5% of relapsing cases lacking identifiable markers for associated conditions, such as neuromyelitis optica spectrum disorder (NMOSD) or multiple sclerosis (MS); these cases are thus classified as relapsing idiopathic optic neuritis (RION). Corticosteroids are typically used for acute management; however, their prolonged use in children poses significant risks, including central obesity, hypertension, and growth impairment, underscoring the need for nonsteroidal, long-term treatment options. Current strategies for preventing recurrence in pediatric RION are limited due to a lack of data on immunosuppressive efficacy and safety. Given its rarity and the challenges of long-term immunosuppression in children, identifying optimal therapeutic approaches remains critical. We report a case of a six-year-old girl with RION, who was initially treated with intravenous methylprednisolone (IVMP) and prednisolone (PSL) tapering, and who experienced recurrence eight months post-treatment. Additional corticosteroids and intravenous immunoglobulin (IVIg) were administered during relapse, but, due to adverse effects, treatment was transitioned to mycophenolate mofetil (MMF), enabling early PSL tapering. With MMF, the patient maintained stable vision and achieved a five-year recurrence-free period without notable side effects. In conclusion, this case suggests MMF's efficacy as a long-term management option for pediatric RION, potentially reducing corticosteroid-related risks.