Pemphigus is an autoimmune intraepidermal blistering disease (1). The autoimmune target of the antibodies is desmoglein, a cadherin-like cell-to-cell adhesion molecule found in desmosomes. In pemphigus vulgaris

© 2014 The Authors. doi: 10.2340/00015555-1811 Journal Compilation © 2014 Acta Dermato-Venereologica. ISSN 0001-5555 Pemphigus is an autoimmune intraepidermal blistering disease (1). The autoimmune target of the antibodies is desmoglein, a cadherin-like cell-to-cell adhesion molecule found in desmosomes. In pemphigus vulgaris (PV), the main antigen is desmoglein 3 (Dsg 3), which is located on the oral mucosa and in the lower layers of the epidermis; in pemphigus foliaceus (PF), the target antigen is desmoglein 1 (Dsg 1), which is structurally located mainly in the upper epidermis (1). It is reported that pemphigus can be induced or exacerbated by radiation therapy (2–11). However, few reports have detailed the serum autoantibody concentrations before and after irradiation (6). We report a case of PF that was well controlled for more than a year but then worsened after electron-beam radiotherapy for extramammary Paget’s disease.