Cutaneous vasculitis occurring in the setting of systemic lupus erythematosus: a multicentre cohort study

Objectives To describe the clinical and pathological features of biopsy-proven cutaneous vasculitis (CV) associated with SLE, focusing on diagnosis classification and impact on overall SLE activity. Methods Retrospective multicentric cohort study including SLE patients with biopsy-proven CV identified by (i) data from pathology departments of three university hospitals and (ii) a national call for cases. SLE was defined according to 1997 revised ACR and/or 2019 ACR/EULAR criteria. CV diagnosis was confirmed histologically and classified by using the dermatological addendum of the Chapel Hill classification. SLE activity and flare severity at the time of CV diagnosis were assessed independently of vasculitis items with the SELENA-SLEDAI and SELENA-SLEDAI Flare Index. Results Overall, 39 patients were included; 35 (90%) were female. Cutaneous manifestations included mostly palpable purpura (n = 21; 54%) and urticarial lesions (n = 18; 46%); lower limbs were the most common location (n = 33; 85%). Eleven (28%) patients exhibited extracutaneous vasculitis. A higher prevalence of Sjogren's syndrome (51%) was found compared with SLE patients without CV from the French referral centre group (12%, P < 0.0001) and the Swiss SLE Cohort (11%, P < 0.0001). CV was mostly classified as urticarial vasculitis (n = 14, 36%) and cryoglobulinaemia (n = 13, 33%). Only 2 (5%) patients had no other cause than SLE to explain the CV. Sixty-one percent of patients had inactive SLE. Conclusion SLE-related vasculitis seems very rare and other causes of vasculitis should be ruled out before considering this diagnosis. Moreover, in more than half of patients, CV was not associated with another sign of active SLE.