Linear IgA bullous dermatosis: a clinical study of 16 cases at National Taiwan University Hospital

Abstract

Linear immunoglobulin A bullous dermatosis (LABD) is a rare autoimmune subepidermal bullous disease. It is defined by continuous linear deposition of IgA in the basement membrane zone on direct immunofluorescence microscopy. The clinical presentations of LABD may mimic other diseases, and data in Taiwanese populations are still lacking. The current study aims to examine LABD status in Taiwan. We reviewed the database at our institute from 1995 to 2008. The gold standard for the diagnosis of LABD is based on continuous linear depositions of IgA in the basement membrane zone on direct immunofluorescence. A total of 16 LABD patients were identified. Mean age at diagnosis was 55 years, and most (> 80%) occurred after the fourth decade. The trunk was most commonly involved (76%). However, in contrast to previous reports, the mucosal involvement was rare in our series (18%). Initial impressions were dermatitis herpetiformis in 8 patients (50%), bullous pemphigoid in 4 patients (25%), and vasculitis, varicella, and pemphigus vulgaris in the remaining 4 patients (25%). Four patients reported a history of drug ingestion shortly before the onset of the disease, and all recovered after discontinuing the offending drugs. One of them had griseofulvin-associated LABD, a case not reported previously. The other three drugs were rifampin, vancomycin and gemcitabine. Among the various regimens, dapsone (100 mg) twice a day achieved the best treatment response in the five treated patients. The rare and diverse presentations of LABD highlight the importance of our study results in aiding clinical diagnosis and planning treatment strategies.