DSG3 and acquired polycythemia vera: Pemphigus are autoimmune diseases, in which intraepidermal acantholytic bullae are caused by the deposition of serum antibodies in desmogleins (Dsg), components of the epidermal desmosomes.1, 2, 3 Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are prevalent in southeastern Brazil.4, 5 In PV, patients are usually elderly, with initial mucosal involvement, and have autoantibodies against Dsg3.