A case of anaphylactoid purpura associated with exacerbation of Crohn's disease

A 64-year-old woman with a 19-year history of Crohn's disease presented at our hospital with complaints of painful knees, abdominal pain, and eruptions on the lower legs. Histopathologically, there were dense neutrophilic perivascular infiltrations in the dermis, vessel wall destruction, and slight leukocytoclasts in palpable purpura, which were compatible with leukocytoclastic vasculitis. Endoscopic examination revealed the characteristic findings of Crohn's disease, and CT showed hypertrophy of the wall of the small intestine. We diagnosed this case as anaphylactoid purpura associated with exacerbation of Crohn's disease. Association of anaphylactoid purpura and Crohn's disease is infrequent, but this case suggests a close relationship between the two diseases.