<prompt> All are seen in Crohns disease EXCEPTPoor perianal hygieneStricture formationCrypt abscessRectum is commonly involved  <response>: Ref: Robbins Pathology, 9th ed. pg. 798-99 Crohns disease can lead to formation of perianal fistula which leads to poor perianal hygiene. The stricture formation seen in Crohns disease occurs due to transmural inflammation. Most common part of GIT involved is ileum in Crohns disease and rectum is spared. Fecal lactoferrin is a highly sensitive and specific marker for detecting intestinal inflammation. Fecal calprotectin levels correlate well with histological inflammation and predict relapses and detect pouchitis. 