Fatal pyoderma gangrenosum in association with C7 deficiency.

Although pyoderma gangrenosum (PG) is often associated with systemic diseases, it has not been reported in association with congenital complement deficiencies. We describe an aggressive and ultimately fatal case of PG in a patient with a congenital C7 deficiency. Deficiencies of C7 can be associated with decreased neutrophil chemotaxis, phagocytosis, and opsonization, similar to the immunologic abnormalities described in patients with PG. Our patient's decreased complement level, if not directly related to the development of PG, may have contributed to the aggressive nature of her disease.