Evidence-based guidelines for the diagnosis and management of adult-onset IgA vasculitis.

IgA vasculitis (IgAV) is an immune complex-mediated small-vessel vasculitis that typically affects the skin, gastrointestinal tract, kidneys and joints. Childhood-onset IgAV is a common disease and usually follows a self-limiting course, whereas adult-onset IgAV is considerably less frequent and is associated with a poorer prognosis. The diagnosis, assessment and management of adult-onset IgAV remain challenging owing to the absence of validated diagnostic criteria for adults and lack of IgAV-specific standardized disease activity scores. Short-term outcomes are mainly determined by gastrointestinal complications, whereas kidney involvement and the risk of progression to chronic kidney disease are the major determinants of long-term prognosis. The treatment of adult-onset IgAV is limited by the paucity of high-quality clinical trials and standardized therapeutic approaches. Here, we present evidence-based, multidisciplinary guidelines for the diagnosis and management of adult-onset IgAV that reflect advances in understanding of pathogenesis, differential diagnoses and treatment over the past two decades. Developed by a panel of leading European experts on the basis of systematic literature review and expert opinion, these guidelines comprise 14 recommendation statements and overarching principles that provide a structured and pragmatic clinical framework for the diagnosis, treatment and follow-up of adult-onset IgAV.