Subcorneal pustular dermatosis (SPD) or Sneddon-Wilkinson disease is a rare, benign, chronic, sterile pustular eruption which is associated with various systemic diseases including immunoglobinopathies, neoplasms, and autoimmune disorders. This paper reports a case of SPD in a patient with diffuse scleroderma in a 37-year-old woman. The hypothesis that immune dysregulation may play a role in the pathogenesis of SPD was supposed by the coexistence of diffuse scleroderma and SPD in our patient.