Nephrotic syndrome relapse in a boy with COVID-19.

Clinical data on coronavirus disease-19 (COVID-19) in children during the management of nephrotic syndrome (NS) is lacking. Patients on prednisolone are compromised hosts at the risk of severe infections. Some infections may induce NS relapse. We describe the clinical course of a child with NS and COVID-19. A 3-year-old boy was admitted with clinical and laboratory findings indicative of NS. Induction therapy with prednisolone (2 mg/kg/day) induced complete remission. While tapering the dose, he was infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). He developed a high fever and periorbital edema. Urinalysis revealed proteinuria (protein-creatinine ratio: 6.3 g/gCr). He was transferred to our hospital for the concurrent management of COVID-19 and NS relapse. As proteinuria worsened, the prednisolone dose was increased to 2 mg/kg/day. Proteinuria gradually improved, and remission was noted a week after initiating full-dose steroid treatment. The fever subsided after 2 days without treatment for COVID-19. Anti-SARS-CoV-2 antibody including IgG levels decreased in the early convalescent phase. To the best of our knowledge, this is the first reported case with the recurrence of NS triggered by the SARS-CoV-2 infection in Asia. SARS-CoV-2 infection may induce NS relapse. Daily administration of full-dose of prednisolone may be effective for managing the recurrence of NS associated with SARS-CoV-2 infection.