RESUMO
The diagnosis of systemic vasculitis requires clinical evidence with appropriate symptoms and physical signs, supported by histological or radiological confirmation. Earlier recognition of these diseases has been facilitated by a greater awareness of their incidence, and also by the more widespread introduction of the anti-neutrophil cytoplasmic antibody (ANCA) test. Early diagnosis provides a greater potential for effective intervention in the course of disease and this may limit subsequent damage. However, an early diagnosis poses the more difficult challenge in the classification of the vasculitides, since traditional classification systems have depended on the presence of well-established manifestations of the disease. The accurate assessment of disease activity and damage in vasculitis has become necessary as a result of significant improvements in survival with the use of chemotherapy. The disease course however is frequently characterised by relapse as well as the scars of irreversible organ damage from disease and drug toxicity. Clinical methods of assessment are simple to apply, reliable and often more effective than any current laboratory test in evaluating the effects of therapy and determining changes in therapy. The increasing use of surrogate clinical measures of disease should provide a greater opportunity to establish the effectiveness of existing and novel therapies in the management of these complex diseases.