Diagnostic Process of Subcorneal Pustular Dermatosis: A Case Report

A 54-year-old man presented to our outpatient clinic with generalized pruritic millet-sized vesicles, pustules, and crusts on the whole body over the past 10 years, which were more dominant in the lower extremities. Due to the difficulty in diagnosis, a series of histopathologic examinations were conducted during the treatment course, and the findings were similar: subcorneal pustules with neutrophils, superficial perivascular and dermal infiltration of lymphocytes, neutrophils, and eosinophils, with no sign of acantholysis. The patient was treated with cyclosporine, prednisolone, doxycycline, colchicine, sulfasalazine, and acitretin; however, his condition did not improve. After showing a dramatic improvement with dapsone, he was finally diagnosed with subcorneal pustular dermatosis (SPD). Various medications commonly used in inflammatory and immunobullous skin diseases were tried but failed to improve the condition; the patient showed a dramatic response only to dapsone. Due to its rarity, careful attention and repeated biopsies are required for diagnosing SPD.