This study focuses on adults with IgA vasculitis, a condition where inflammation affects the blood vessels, causing symptoms such as skin rash, joint pain, and potential kidney problems. The study aims to determine if adding the medication rituximab to standard treatment with glucocorticoids (steroid medications) is more effective than using glucocorticoids with a placebo in treating newly diagnosed or relapsing cases of the disease.

The treatment involves receiving either rituximab or placebo through an intravenous infusion (delivered directly into a vein), along with glucocorticoid medication. The rituximab or placebo will be given as an infusion, while the glucocorticoids will be taken as prescribed by the study doctor. The study medication (rituximab or placebo) will be administered during the first months of the study.

Participants will be monitored for 12 months to assess how well the treatment works and to check for any side effects. During this time, doctors will track various aspects of the disease, including kidney function, blood tests, and overall health status. The study will measure how many patients achieve remission (improvement of symptoms) while being able to stop taking glucocorticoids completely at specific time points during the study.