How can relapses be detected and prevented in primary systemic small-vessel vasculitides?

Relapse is an important outcome measure in patients with Wegener's granulomatosis, microscopic polyangiitis and Churg-Strauss syndrome. Although relapses are common in these diseases, it remains unclear why these occur and whether they are influenced by exogenous or endogenous factors. A key to minimizing the consequences of relapse is early recognition through monitoring. This is particularly essential to detect glomerulonephritis that is often asymptomatic and can be rapidly progressive. While the presence of relapse is currently based on objective evidence of active disease, investigations seek to identify factors that may distinguish patients at risk of relapse or markers that reliably predict the occurrence of relapse prior to organ injury. With the ability to successfully induce remission and the toxicities of available therapies, the relapse rate has become a critical issue in assessing the efficacy of new treatments. Recent clinical trials have sought to investigate safer therapeutic options that decrease disease relapse.