Pemphigus is an autoimmune disease in which blisters form on the skin and mucous membranes due to damage to the junctions between epidermal cells[1]. The disease is divided into two main subtypes – pemphigus vulgaris and pemphigus foliaceus, which differ in the depth of damage and clinical manifestations[1]. Pemphigus vulgaris affects the deeper layers of the epidermis and often occurs on the oral mucosa, while pemphigus foliaceus affects the more superficial layers and does not occur on the mucosa[1]. Transition between these two subtypes is very rare, with the change from pemphigus foliaceus to pemphigus vulgaris even more unusual than the reverse[1]. The article describes the case of a 48-year-old man in whom pemphigus foliaceus transformed into pemphigus vulgaris five years after the initial diagnosis[1]. The mechanism of this transition is not completely clear, but one of the possible causes is the so-called epitope-spreading phenomenon, in which the immune system begins to attack other hidden proteins in the tissue[1].