Small vessel vasculitides

Small vessel vasculitis can be associated with immune complex deposition, as in Henoch–Schönlein purpura or systemic lupus erythematosus, or with minimal immune deposits, as in Wegener's granulomatosis, microscopic polyangiitis or renal-limited vasculitis. The latter conditions are associated with circulating anti-neutrophil cytoplasm antibodies (ANCA) and are the most common causes of rapidly progressive glomerulonephritis. This review describes recent advances in the understanding of the pathogenesis underlying these conditions and reviews common presentations. Consideration is given to recent clinical trials in the management of ANCA-associated vasculitides.