Urticarial vasculitis in pediatric systemic lupus erythematosus

Background/Objectives: To determine the prevalence of urticarial vasculitis (UV) in a pediatric systemic lupus erythematosus (pSLE) cohort of Arab ethnicity from Oman and to describe their demographic, clinical, and laboratory features. Methods: We conducted a retrospective multicenter study among pediatric rheumatology centers in Oman over a 10-year period from 2008 to 2018. Analyses were performed using univariate statistics. Results: A total of 148 pSLE under the age of 13 years were included of which 30% (n = 44) were men. The overall mean age at SLE diagnosis was 7.6 ± 3.5 years while the mean disease duration was 10.1 ± 5.4 years. UV was diagnosed in 36% (n = 53) of pSLE patients. Patients with pSLE and UV were more likely to be male (57% vs 15%; P <.001), diagnosed at a younger age (5.9 vs 8.5 years; P <.001), have a family history of SLE (53% vs 36%; P =.044), and have associated conjunctivitis, (32% vs 5.3%; P <.001) but less likely to have CNS involvement (7.6% vs 20%; P =.045) or hematological manifestations such as leukopenia (9.4% vs 24%; P =.028) and thrombocytopenia (5.7% vs 18%; P =.045). This subgroup was also more likely to be associated with low C3 complement count (94% vs 66%; P <.001) and positive cytoplasmic ANCA (11% vs 0%; P =.022). Conclusion: We report a high occurrence of UV in a pSLE cohort associated with unique demographic, clinical, and laboratory features.