Pyoderma Gangrenosum in an Ulcerative Colitis Patient on Vedolizumab.

Pyoderma gangrenosum is a rare neutrophilic dermatosis that presents as a tender, rapidly progressive ulcer with violaceous, undermined borders. Pathophysiology is multifactorial and has been suggested to involve neutrophil dysfunction, increased T-cell activation, and inflammatory mediator release, often in settings that are known to have autoimmune or genetic diseases. Some medications that modify the immune response have been described to trigger pyoderma gangrenosum.