Henoch–schonlein purpura following exposure to SARS-CoV2 vaccine or infection: a systematic review and a case report.

Background: Henoch–Schonlein purpura (HSP) is an IgA-mediated systemic small-vessel vasculitis (IgAV) that typically presents with a variable tetrad of symptoms. HSP if often preceded by respiratory tract infections, vaccinations, drugs or malignancies. During the recent COVID-19 pandemic multiples cases of HSP have been described after both infection and vaccination for SARS-CoV2. This study aims to perform a systematic review of literature and describe an additional complicated case of de-novo HSP appeared after the administration of the third dose of a mRNA-SARS-CoV2 vaccination. Methods: Electronic bibliographic research was performed to identify all the original reports describing cases of de-novo HSP or IgAV appeared after respiratory infection or vaccine administration for SARS-CoV2. We included all case series or case reports of patients who respected our inclusion and exclusion criteria. Results: Thirty-eight publications met our pre-defined inclusion criteria, for an overall number of 44 patients. All patients presented with palpable purpura variable associated with arthralgia, abdominal pain or renal involvement. Increased levels of inflammation markers, mild leukocytosis and elevated D-dimer were the most common laboratory findings. Up to 50% of patients presented proteinuria and/or hematuria. Almost all skin biopsies showed leukocytoclastic vasculitis, with IgA deposits at direct immunofluorescence in more than 50% of cases. Conclusions: Our results suggest that the immune response elicited by SARS-CoV2 vaccine or infection could play a role in the development of HSP. Current research suggests a possible role of IgA in immune hyperactivation, highlighted by early seroconversion to IgA found in some COVID-19 patients who develop IgA vasculitis. [ABSTRACT FROM AUTHOR]