title: When it is not inflammatory bowel disease: differential diagnosis.
abstract: OBJECTIVE
  Inflammatory bowel diseases (IBDs) represent a heterogeneous entity whose diagnosis is sometimes difficult to ascertain. Many pathological processes may mimic IBD phenotypes. Among the classical differential diagnoses are enteric infections and infestations as well as drug toxicity. However, recently, more specific differential diagnoses have been included, including monogenic causes of gastrointestinal tract inflammation, particularly in young children. The purpose of the present review is to describe the differential diagnosis of IBD, putting it in a specific clinical and demographic context. This differential diagnosis will be discussed specifically for young children, elderly patients, and immunosuppressed patients.
  
  
  RESULTS
  We will focus on the most recent findings and concepts, including monogenic diseases in young children, diverticular disease-associated colitis in elderly patients, and toxic colitis in patients receiving immunosuppressants such as mycophenolate mofetil or biologics such as ipilimumab.
  
  
  CONCLUSIONS
  The aim of this review is to alert the clinician dealing with IBD, concerning a series of specific diagnoses that should be recognized because they may require specific treatment, different from the ones of classical idiopathic IBD.
authors.affiliation: Department of Gastroenterology, Centre Hospitalier Universitaire, Liège, Belgium.
authors.forename: Edouard
authors.initials: E
authors.lastname: Louis
mesh_terms: D000367:Age Factors; D003092:Colitis / Q000139:chemically induced / Q000175:diagnosis; D003937:Diagnosis, Differential; D030342:Genetic Diseases, Inborn / Q000175:diagnosis; D006801:Humans; D007108:Immune Tolerance; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis*; D009894:Opportunistic Infections / Q000175:diagnosis; D014385:Tuberculosis, Gastrointestinal / Q000175:diagnosis