[A Case of Pemphigus Vulgaris Showing a Local Nose Erosion as the First Clinical Manifestation].

A 73-year-old male noticed a localized nose erosion that we thought was possibly an exacerbation of skin erosion due to the direct influence of friction from wearing a mask. Blood examination revealed a remarkable increase in serum anti-desmoglein-1 and anti-desmoglein-3 antibodies. A skin biopsy showed acantholysis in the epidermal granular layer. Based on the clinical manifestation and laboratory examination, we diagnosed his eruption as anti-desmoglein-1 and anti-desmoglein-3 antibody - positive pemphigus vulgaris. His skin eruption responded well to oral prednisolone and azathioprine and gradually improved. Pemphigus was a candidate as a differential diagnosis in this case, in which the direct mechanical friction from wearing a mask was thought to be an exacerbating factor of skin eruption.