Pyoderma gangrenosum followed by subcorneal pustular dermatosis in a patient with IgA paraproteinemia. Six months after the occurrence of pyoderma gangrenosum, subcorneal pustular dermatosis developed in a 60-year-old woman. The patient's serum was found to contain an IgA-lambda paraprotein. Although similar cases have been reported, this case is unique in that a distinct episode of pyoderma gangrenosum was followed by subcorneal pustular dermatosis. 