Infectious causes of diarrhea in the differential diagnosis of inflammatory bowel disease

The infectious causes of enteritis and colitis are numerous. However, the actual clinical differential diagnosis with either ulcerative colitis or Crohn's disease is usually not a significant problem, except, of course, in two circumstances: (1) acute onset of diarrhea with or without rectal bleeding, and (2) patients who have AIDS, are immunocompromised, or are male homosexuals. However, if one bears in mind that rectal bleeding and mucosal abnormalities which are diffuse and uniform are the hallmark of ulcerative colitis, that Crohn's disease has perianal and external manifestations as its significant clinical hallmark, and both diseases tend to be chronic and recurrent, the clinical distinction can usually be made. However, it is important to recognize that there is an increasing awareness of intestinal infections, partly as a result of study of male homosexuals or patients with AIDS, as well as increased recognition of other infectious causes of diarrhea, including traveler's diarrhea, that associated with C. difficile, and that found with infection due to Campylobacter. As is usually the case in clinical medicine, however, careful and accurate history, attention to detail on physical and sigmoidoscopic examination, and laboratory (usually stool culture) data will lead to the appropriate diagnosis.