LAUSR

Background There is a growing literature reporting the association between proton pump inhibitor (PPI) use and subacute cutaneous lupus erythematosus (SCLE). Aims To compare the clinical characteristics of a cohort of patients with PPI-induced SCLE, their clinical course and treatment with a control group of primary SCLE patients not exposed to PPI. Methods We conducted a matched case–control study in a tertiary referral setting at the Louise Coote Lupus Unit. There were 64 SCLE patients: 36 with PPI-induced SCLE and 28 patients with primary SCLE. Results Twenty-six patients (72%) had pre-existing SLE in the PPI-induced SCLE group. Lower limb skin lesions were significantly more prevalent in the PPI group (p < 0.0001). The prevalence of anti-Ro and anti-Ro-52 antibodies was numerically higher in the PPI group (64% and 60%), respectively, compared with 46% and 42% in the primary SCLE group. Peripheral blood eosinophils were normal in all patients in the PPI group. Thirteen patients underwent skin biopsy in the PPI group and 12 had histology in keeping with SCLE. The median time to presentation was 8 months with a median resolution period of 6 weeks. PPIs were stopped in 34 patients, while 2 patients continued treatment for other clinical indications. Twelve patients received concurrent oral corticosteroids. Two patients had severe SCLE in the form of Toxic Epidermal Necrolysis requiring critical care admission and were managed with corticosteroids, IV immunoglobulin and/or belimumab. Conclusion Lower limb involvement is a pointer to PPI-induced SCLE which is likely a class effect with all PPI.