[Psoriasis vulgaris as a trigger for a superficial multilocular pyoderma gangrenosum?]

We report on a 60-year-old man with psoriasis vulgaris who had developed disseminated ulcerations of different sizes over the complete integument over a period of 3 months. The initial examination revealed approximately 150 clearly defined ulcerations, which were mostly reported to be painless. The histopathology report of a biopsy taken from the border area of an ulceration showed a nonspecific inflammation with a predominantly neutrophilic infiltrate. In the synopsis of all results, after excluding relevant differential diagnoses, we diagnosed a superficial multilocular pyoderma gangrenosum that had possibly developed in the areas of the preexisting psoriasis vulgaris. Reports of superficial multilocular pyoderma gangrenosum, a variation of pyoderma gangrenosum, are extremely rare. This condition is characterised by multiple superficial, chronically persistent ulcerations. These ulcerations are often described as indolent and usually develop from a pustule in the area of a preexisting condition or trauma. Up to now, psoriasis vulgaris has seldom been described as a trigger for pyoderma gangrenosum. The treatment is very difficult and is based on local and/or systemic immunosuppression. In this patient's case, considerable improvement was attained with a topical polyhexanide gel in combination with moist wound therapy, with no systemic immunosuppression. Our case report underscores that physicians should keep in mind the rare variation of superficial multilocular pyoderma gangrenosum in the differential diagnosis of multiple disseminated, painless ulcerations over the complete integument in patients with psoriasis vulgaris.