ANCA-associated vasculitis flare might be provoked by COVID-19 infection: a case report and a review of the literature.

Mesangial immunoglobulin A (IgA) deposition is the hallmark of IgA nephropathy (IgAN). In some cases, crescentic involvement that might be associated with systemic leucocytoclastic vasculitis is documented. In such cases, the disease is called Henoch-Schönlein purpura (IgA vasculitis). Even more rarely, the coexistence of IgAN and anti-neutrophil cytoplasmic antibody (ANCA) seropositivity has been reported. IgAN might be complicated by acute kidney injury (AKI) due to different causes. Herein we present a patient with mesangial IgA deposition and ANCA seropositivity who developed AKI, haematuria and haemoptysis during the course of coronavirus disease 2019 (COVID-19) disease and was diagnosed with ANCA-associated vasculitis based on clinical, laboratory and radiological findings. The patient was treated successfully with immunosuppressive therapy. We also made a systematic review of the literature to reveal and present the cases with COVID-19 and ANCA-associated vasculitis.