A case of vulvar pyoderma gangrenosum associated with collagenous colitis.

Pyoderma gangrenosum is a reactive inflammatory dermatosis which belongs to the spectrum of neutrophilic dermatoses. Due to a lack of diagnostic criteria, pyoderma gangrenosum is mainly a diagnosis of exclusion. It is rarely observed on the perineum, and vulvar involvement is even less frequent. Collagenous colitis is an idiopathic inflammatory colonic disease that is included in the microscopic colitides. The colonic mucosa and the crypt architecture are preserved but histologic alterations are found. We describe a case of collagenous colitis associated with vulvar pyoderma gangrenosum that improved spectacularly with cyclosporine 3 mg/kg/day and the twice-daily application of topical tacrolimus 0.1%.