[Prospective study of factors associated with leukocytoclastic vasculitis].

The origin of leukocytoclastic vasculitis (LV) being often difficult to determine, we have undertaken since 1980 a prospective study of factors associated with LV. We selected 53 patients whose LV was clinically predominant, and excluded patients in whom LV was an expected phenomenon in a known autoimmune or infectious disease. Twenty-eight of the 53 patients presented with a typical Gougerot-Ruiter disease, 15 with a bullous or necrotic form of the disease and 10 with urticarial lesions. Detail of the prospective laboratory tests performed is given in table I. Correlations between laboratory values and LV-associated factors were significant with the decrease of complement but not with the presence of circulating immune complexes, rheumatoid factor, cryoglobulin or direct immunofluorescence test positivity. Most of the associated factors in our series were infectious agents (streptococci, hepatitis virus), immunological agents (rheumatoid factor, cryoglobulin) or drugs known to be potential LV-inductors; other factors were less common or quite recently described (enterovirus, Yersiniae, cirrhosis, primary liver cancer, Chlamydiae, refractory anemia with an excess of myeloblasts. We do not feel that a large series of laboratory tests should be performed in every case of LV. The clinical context and simple laboratory tests, such as blood cell count, complement assay, plasma electrophoresis and a search for rheumatoid factor should be enough to guide the clinician and help him decide whether further investigations are needed. However, it should be noted that in some cases without clinical pointers only full virological evaluation enabled us to determine that enteroviruses may be involved in the pathogenesis of LV.