Ulcerative colitis and the skin.

The association between ulcerative colitis and various abnormalities of the skin, especially pyoderma gangrenosum, has been accepted for many years. The underlying aberrations in either of the organ systems, as well as the basis of their association, however, remain obscure. Several large series of ulcerative colitis patients are reviewed to emphasize the important concomitant cutaneous findings, and investigations into the pathogenesis of pyoderma gangrenosum are discussed.