Viral Infections May Be Associated with Henoch–Schönlein Purpura

Henoch–Schönlein purpura or IgA vasculitis is the most common type of pediatric vasculitis that may affect adults as well. It is classified as a type of small-vessel vasculitis. It can cause cutaneous and systemic symptoms with a minority of patients developing kidney failure. Little is known about the specific pathophysiology of this disorder, except that it is believed to occur in individuals with abnormally glycosylated IgA1. Serum aberrant IgA1 may form large antigen–antibody complexes which, due to a defective clearance, are able to deposit in the small vessels of the skin, kidney, gut, and joints. A variety of factors, including infectious agents, drugs, and vaccines, have been identified as potential triggers. The majority of cases are preceded by upper respiratory tract infections, and seasonal variations suggest a link with many pathogens. The etiologic agent most frequently associated with IgA vasculitis historically have been group A β-hemolytic streptococcus and common respiratory tract viruses. However, during the current coronavirus pandemic, SARS-CoV-2 infection was identified as a main trigger factor. In addition, IgA vasculitis has been observed following COVID-19 immunization. This review provides insights into the state of the art on the relationship between viral infections, viral vaccines, and Henoch–Schönlein purpura.