Characterization of non-IgA vasculitis: Demographic, clinical, and treatment-related features in a retrospective analysis of 28 biopsy-confirmed cases from a German university hospital.

Non-IgA vasculitis is a rare disease that belongs to the group of small-vessel vasculitides. Due to nomenclature and classification changes introduced in 2018, there are few published data under this name. The aim of this study is to characterize non-IgA vasculitis as an independent vasculitis entity in terms of demographic, clinical, and treatment-related features. A retrospective data analysis of patients with biopsy-confirmed non-IgA vasculitis treated at the Department of Dermatology at the University Medical Center Hamburg-Eppendorf between January 1, 2018, and December 31, 2022, was performed. A total of 28 patients with non-IgA vasculitis were included; 53.6% (15/28) were women and 42.9% (12/28) were older than 71 years. Previous infection as a possible triggering factor was found in 42.6% (12/28) of the cases. Palpable purpura was the most common skin finding (78.6%, 22/28) and 28.6% patients (8/28) had skin lesions above the waist. On direct immunofluorescence, C3 (89.3%, 25/28) was the most frequent deposition, followed by fibrinogen (71.4%, 20/28) and IgM (53.6%, 15/28). Hospitalization was required in 85.7% (24/28), with a mean hospital stay of 9.4 ± 4.1 days. No fatal courses were reported. This study is the first characterization of non-IgA vasculitis based on patient cases from Germany and contributes to a better understanding of non-IgA vasculitis as an independent entity. Non-IgA vasculitis primarily affects older patients of both sexes, with most cases having an identifiable trigger. Our results indicate that cutaneous manifestations often extend beyond the lower legs. Treatment is usually required in the inpatient setting and requires a longer stay than other dermatological conditions. With proper treatment, the disease is not expected to be fatal.