[Immunology in clinical practice IX. Systemic vasculitis].

A diagnosis of vasculitis generally requires histopathological proof of vasculitis, particularly because many other disease entities may mimic vasculitis ('vasculitis-look-alikes'). Vasculitis can be primary (idiopathic) or secondary to other diseases, especially infectious diseases. The primary vasculitides are classified according to the size of the vessels involved and the nature of the inflammation, in combination with clinical symptoms. The detection of autoantibodies, particularly the antineutrophil cytoplasmic antibodies (ANCA), in some of the primary vasculitides, has facilitated the diagnosis of those diseases and has given more insight into their pathophysiology. Treatment of primary vasculitis still consists of corticosteroids whether or not in combination with immunosuppression. New insights in pathophysiology may provide more specific and less toxic treatment modalities.