A 58 year old man was diagnosed with Crohn's disease 2 years earlier. He developed a pustular rash on the arms and legs 3 months before the current admission for a psoas abscess. The rash was not painful, and he had no pruritus, arthralgias, or myalgias. Medications included Ascol, toprol, cipro, Tylenol, and Immodium. He had a mild leukocytosis and anemia; otherwise, chemistries, coagulation studies, connective tissue disease studies, P-ANCA, C-ANCA, hepatitis profile, syphilis serology, Tzanck smear and cultures of pustules, urinalysis, stool for C. difficile toxin and enteric pathogens were normal or negative. Stool examination showed numerous polymorphonuclear leukocytes. Fluid drained from the psoas abscess grew Citrobacter freundii and Enterococcus faecium. The skin biopsy of a pustule showed a leukocytoclastic vasculitis and direct immunofluorescence was negative. These findings are most consistent with a vasculitis induced by Crohn's disease.