Allergy-induced urticaria of the colon.

This article reports 2 adult patients who had developed an acute allergic reaction to food ingredients or medications, respectively. Both patients presented with concurrent urticaria of the skin and colon. The latter finding appeared as numerous raised plaques of the colonic mucosa on radiographic and computed tomography (CT) of the abdomen. The urticarial lesions affecting the skin and large bowel resembled each other and resolved after treatment with antihistamines. Pertinent clinical data and previously published cases of this unusual entity are briefly reviewed.