Vasculitis flare after COVID-19: report of two cases in patients with preexistent controlled IgA vasculitis and review of the literature.

COVID-19 has been related to several autoimmune diseases, triggering the appearance of autoantibodies and endothelial dysfunction. Current evidence has drawn attention to vasculitis-like phenomena and leukocytoclastic vasculitis in some COVID-19 patients. Moreover, it has been hypothesized that COVID-19 could induce flares of preexisting autoimmune disorders. Here, we present two patients with previously controlled IgA vasculitis who developed a renal and cutaneous flare of vasculitis after mild COVID-19, one of them with new-onset ANCA vasculitis. These patients were treated with glucocorticoids and immunosuppressants achieving successful response. We also provide a focused literature review and conclude that COVID-19 may be associated with triggering of vasculitis and could induce flares of previous autoimmune diseases.