Vasculitis in lupus

Prevalence and associated features of vasculitis in lupus

It is difficult to obtain exact figures for the prevalence of vasculitis in lupus, as the definition of what constitutes vasculitis differs between different authors. A recent review cites a prevalence of 11% to 36%. Most of the evidence comes from large retrospective studies in single centers. Drenkard et al. in 1997 reported on a cohort of 540 Mexican patients followed for a mean of 7.2 years to 1990. Of these patients, 194 (36%) were reported to have suffered at least one episode of vasculitis, though this was only proved by histology or imaging in 54 cases (28%). The majority of cases (174) had cutaneous vasculitis, which occurred with no visceral involvement in 164 patients, and over 90% of biopsies were of the skin. Among 29 patients with visceral vasculitis, most (19) had mononeuritis multiplex. There was only one case of mesenteric vasculitis. Perhaps because of the predominance of cutaneous disease there was no difference in mortality between the 194 SLE patients with vasculitis and the 346 without vasculitis, but patients with visceral involvement were more likely to die than those with cutaneous vasculitis ( P = .006). In a more recent retrospective study from Barcelona, Ramos-Casals et al. reported on 670 patients with SLE seen between 1980 and 2004. Their figure for prevalence of vasculitis was much lower than that of the earlier Mexican study at 11%, but they also found that the majority of cases (89%) were cutaneous vasculitis. Their lower prevalence may have been due to a stricter definition of vasculitis; 45/76 patients (59%) with vasculitis in the Spanish study had histological and/or imaging evidence and the others had typical vasculitic skin lesions assessed by a dermatologist. Of 14 patients with visceral vasculitis, 7 had mononeuritis (proved by biopsy).

In Drenkard’s study, patients with vasculitis had longer SLE disease duration ( P = .05) and younger age of onset ( P = .006) than those with no vasculitis. In the study of Ramos-Casals, the patients with vasculitis had higher mean activity scores measured by the European Consensus Lupus Activity Measure ( P < .001). Regarding serological markers, Ramos-Casals et al. found that vasculitis was associated with anemia ( P < .001), ESR over 50 ( P < .001), and antiLa/SSB antibodies ( P = .014, though only 19% of patients with vasculitis were actually antiLa-positive) in multivariate analysis. Positivity for antiphospholipid antibodies (aPL) was significantly associated with vasculitis in univariate but not multivariate analysis with 52% of patients with lupus vasculitis being aPL-positive.

Ramos-Casals et al. reported that 65/76 patients had small vessel vasculitis while the other 11 had medium vessel vasculitis. Histologically, 29 of 45 patients who had a biopsy had leukocytoclastic vasculitis and 10 had necrotizing vasculitis. All patients with medium vessel vasculitis, but only 5% of those with small vessel vasculitis, had visceral involvement.