Depending on the level of pustule formation, IgA pemphigus can be divided into two major clinical and histological subtypes: intraepidermal neutrophilic dermatosis (IEN), which is characterized by suprabasilar pustules located at the lower or entire epidermis and associated with the presence of IgA antibodies against Dsg1 or Dsg3, and other yet-unidentified antigens; and subcorneal pustular dermatosis (SPD), in which patients exhibit subcorneal pustules in the upper epidermis and auto-reactive IgA binds desmocollin 1 (Dsc1) (Hashimoto et al., 1997; Karpati et al., 2000; Yasuda et al., 2000). Here, DSC1 is linked to Platelet storage pool disease.