Subcorneal pustulosis and Pyoderma gangrenosum associated with a biclonal gammopathy

Pyoderma gangrenosum and subcorneal pustulosis are two neutrophilic dermatoses. Their occurrence in the same patient is rare and may be related to an IgA dysglobulinemia. We report a case presenting these two conditions associated with a biclonal benign IgA and IgG gammopathy. A 67-year-old man exhibited typical pyoderma gangrenosum associated after three years duration with subcorneal pustulosis lesions, confirmed by cutaneous biopsy. Laboratory results showed a biclonal benign IgA and IgG kappa gammopathy. Therapeutic management was difficult: Pyoderma gangrenosum responded well to corticosteroids but subcorneal pustulosis management was harder and treatments were poorly effective.Pyoderma gangrenosum and subcorneal pustulosis are a part of the neutrophilic spectrum. Their association has been only reported in eleven patients. In eight cases, an IgA dysglobulinemia was associated suggesting its responsibility in the occurrence of both dermatoses. Treatments are various and not fully effective. If the Pyoderma gangrenosum usually responds to corticosteroids, the subcorneal pustulosis treatments are not well defined and often not efficient. Our case illustrates the dissociated evolution of these two dermatoses and their difficult global management. During the follow-up, a regular search for dysglobulinemia is required in order to detect malignant transformations.