Snapshot A 33-year-old woman with irritable bowel syndrome (constipation type) presents to her primary care physician for evaluation of severely painful bowel movements. She reports that onset occurs during the bowel movement and may persist for hours afterward causing significant fear of having bowel movements. She also notes small amounts of bright red blood on the toilet paper. Introduction Clinical definition linear tear of the distal anal canal acute or chronic Associated conditions inflammatory bowel disease sexually transmitted infections acquired immunodeficiency syndrome squamous cell carcinoma of the anus Epidemiology Demographics equal in males and females younger and middle-aged Risk factors low fiber diet constipation chronic diarrhea prior anal surgery hypertonicity of the internal anal sphincter ETIOLOGY Pathogenesis trauma to the distal anal canal most often from a hard bowel movement anal sphincter spasm and increase in anal sphincter pressure Presentation Symptoms painful bowel movement bright red blood on toilet paper or stool Physical exam tear of the anal epithelium and mucosa most often at the midline, posterior more than anterior sentinel pile or skin tag, if chronic IMAGING Anoscopy or proctosigmoidoscopy if poor healing or recurrent to evaluate for other pathologies if chronic, hypertrophied papilla above the fissure STUDIES Diagnostic testing perianal examination direct visualization of the anal fissure is diagnostic login to view 3 more bullets if lateral to midline must rule out alternative cause login to view 3 more bullets Differential External hemorrhoid distinguishing factor hemorrhoid visualized on exam Anal cancer distinguishing factor off midline location bulky appearance Treatment First-line Medical management fiber supplementation and stool softeners login to view 1 more bullet topical lidocaine and sitz bath login to view 1 more bullet nitroglycerin ointment and calcium channel blockers login to view 2 more bullets Second-line interventional botulinum toxin injection to the anal sphincter surgical lateral internal sphincterotomy Complications Chronic anal fissure Fecal bacterial infection of wound