Clinical and immunological features of pemphigus relapse

Background: More than half of patients with pemphigus experience relapse during the disease course. The risk factors and clinical and immunological characteristics of relapse remain largely unclear. Objectives: To elucidate the risk factors and clinical features of pemphigus relapse. Methods: We carried out a retrospective review of the clinical records of 42 cases of pemphigus at a single centre. Results: Sixty-two per cent of patients experienced relapse, usually when oral prednisolone was tapered to around 0·1 mg kg−1. In mucocutaneous pemphigus vulgaris (mcPV), the initial doses (mean ± SD) of prednisolone were significantly lower in patients with relapse (0·78 ± 0·24 mg kg−1) than in those without relapse (1·01 ± 0·01 mg kg−1). At relapse, mcPV shifted to mucosal dominant PV (mPV; 40%), pemphigus foliaceus (PF) (20%) or ‘other’ (20%). In contrast, relapsing mPV and PF had the same clinical phenotypes as the initial phenotypes. Patients with both anti-desmoglein (Dsg)1 and anti-Dsg3 antibodies at onset had recurrence with anti-Dsg3 antibodies alone (40%), with both anti-Dsg1 and anti-Dsg3 antibodies (30%), with anti-Dsg1 antibody alone (20%) or were subthreshold (10%). Conclusions: mcPV shows transitions in clinical phenotype and autoantibody profile at relapse. At least 1 mg kg−1 daily of prednisolone, especially for patients with mcPV, and prudent tapering around 0·1 mg kg−1 may lead to better outcomes. © 2018 British Association of Dermatologists