Vasculitis in systemic lupus erythematosis.

Vasculitis in connective tissue diseases is not an uncommon complication. Vasculitis complicates both rheumatoid arthritis and systemic lupus erythematosis (SLE) in about 4% of cases. Cutaneous lesions, representing small-vessel involvement, are most common; however, widespread, necrotizing visceral medium-and large-vessel involvement, mimicking primary vasculitic syndromes, may also occur. Connective tissue disease-associated vasculitis is separated from primary vasculitis syndromes in classification schemes. Granulomatous large-vessel disease does not occur in connective tissue diseases, suggesting a different pathogenesis. In most disorders, the etiology of vascular inflammation in not completely understood, but basic pathogenic mechanisms can often be distinguished. The role of immune complexes in the inflammatory manifestations of SLE is recognized, and other pathogenic factors such as antineutrophil cytoplasmic antibodies, common in other vasculitides, are infrequent. A diverse spectrum of clinical features, due to inflammatory involvement of arterial and venous vessels of all sizes, characterize several connective tissue diseases including Behçet's disease and SLE. The recognition of disease manifestations due to vasculitis in these disorders has important implications for treatment and may be critical to reduce morbidity and mortality.