P040 Clinical features, treatment and treatment response of 24 patients with epidermolysis bullosa acquisita

Abstract Epidermolysis bullosa acquisita (EBA) is a rare immunobullous disorder characterized by skin fragility and mucocutaneous erosions. It is often recalcitrant to treatment. The diagnosis of EBA relies on the correlation of clinical and immunofluorescence findings, as it can share features with other subepidermal bullous disorders. There are relatively few descriptive studies that document human leucocyte antigen associations of the disease, immunofluorescent findings, clinical characteristics, treatments and treatment response. In this study, we report these parameters in 24 patients with EBA. All patients met the following diagnostic criteria: (i) presence of mechanobullous skin lesions and/or mucosal erosions and (ii) positive indirect immunofluorescence localizing to the base of salt-split skin and (iii) presence of anti-type VII collagen (anti-col7) antibodies as identified by enzyme-linked immunosorbent assay. The mean age of the patients was 58 years, with a mean age of onset of EBA of 46 years. One-half (50%) of the patients in our series were White, 33% were of African Caribbean ancestry and 17% were of Asian, Turkish, mixed or Middle Eastern ethnicity. During the course of their disease, all patients had skin fragility and oral lesions. In total, 29% (n = 7) each had ocular and laryngeal involvement and 21% (n = 5) each had oesophageal and genital involvement. Most patients required combination treatment with multiple different immunosuppressive agents. All patients were treated initially with oral prednisolone and some patients required oral dapsone (n = 20), intravenous corticosteroids (n = 11), mycophenolate mofetil (n = 19) and azathioprine (n = 7). Overall, 63% (n = 15) of patients were treated with intravenous immunoglobulin (IVIG) and 63% (n = 15) with rituximab. Out of the 24 patients in this case series, 25% (n = 6) had active disease despite treatment, with 17% (n = 4) having active EBA until death. Other studies have suggested that circulating anti-col7 can be used as a biomarker for EBA disease severity. However, we did not observe any association between anti-col7 titre and disease status (P = 0.27), need for rituximab (P = 0.35) or need for IVIG treatment (P = 0.62). In conclusion, the treatment of EBA can be challenging, and most patients in this series required combination treatment with corticosteroids, dapsone and an intravenous immunosuppressant. The treatment-refractory nature of the disease is also reflected by the high proportion of patients requiring rituximab, and 25% of patients having ongoing active disease despite maximal therapy.