Rituximab-Induced Serum Sickness in a Seven-Year-Old Child With Nephrotic Syndrome

The aim of this article is to report an unusual side effect of rituximab in a child. We describe a seven-year-old boy with steroid-dependent nephrotic syndrome who presented with fever and severe polyarthralgia after his first dose of rituximab. The onset of symptoms 13 days after rituximab administration, the self-limited evolution of symptoms, the exclusion of other causes, and the presence of similar reports led to the diagnosis of rituximab-induced serum sickness as a possible adverse reaction. The benefits of rituximab have been reported in steroid-dependent nephrotic syndrome with frequent relapses. However, most of the available evidence derives from studies in adults. The communication and analysis of pharmacovigilance data, both from spontaneous reporting and active surveillance, are important for defining the role of new drugs in treatment.