Renal Involvement in IgA Vasculitis: Bridging the Pathophysiology and Management of IgA Nephropathy

IgA vasculitis (IgAV), formerly known as Henoch-Schönlein purpura, is the most common systemic vasculitis in children but also affects adults, often with more severe renal manifestations. This review highlights the pathophysiology, clinical spectrum, and particularly the renal involvement of IgAV, which determines long-term prognosis. Renal manifestations, observed in up to 50% of patients, range from isolated hematuria and proteinuria to nephrotic syndrome and progressive glomerulonephritis. Biopsy is warranted in patients with significant proteinuria (≥1 g/day), nephrotic syndrome, or rapidly deteriorating renal function. Histopathology typically reveals mesangial IgA deposition and variable degrees of glomerular proliferation, including crescent formation in severe cases. Prognostic biomarkers such as persistent proteinuria, elevated creatinine, and biopsy findings of crescents or endocapillary proliferation guide risk stratification. Management of mild renal involvement is supportive, while moderate to severe disease requires corticosteroids and immunosuppressive agents like mycophenolate or cyclophosphamide. Long-term follow-up is essential, as adult patients with severe renal disease are at risk for progression to chronic kidney disease or end-stage renal failure. Multidisciplinary care is recommended to optimize outcomes. Understanding the renal spectrum of IgA vasculitis and promptly identifying high-risk patients allows for early intervention, which may alter the disease trajectory. Ongoing research into predictive biomarkers and tailored therapies holds promise for improving prognosis in patients with IgAV-related nephritis.