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Key Features

  • Linear or rocket-shaped ulcers, usually < 5 mm

  • Most commonly occur in the posterior midline; 10% occur anteriorly

  • Arise from trauma during defecation

Clinical Findings

  • Severe, tearing pain during defecation followed by throbbing discomfort

  • May lead to constipation because of fear of recurrent pain

  • Mild associated hematochezia

  • With chronic fissures, there is fibrosis and a skin tag at the outermost edge (sentinel pile)


  • Diagnosis is confirmed by visual inspection of the anal verge while gently separating the buttocks

  • Digital and anoscopic examinations may cause severe pain so may not be possible

  • Fissures that occur off the midline suggest

    • Crohn disease

    • Syphilis

    • Tuberculosis

    • HIV/AIDS

    • Anal carcinoma


  • Fiber supplements, stool softeners

  • Sitz baths

  • Topical anesthetics (5% lidocaine; 2.5% lidocaine plus 2.5% prilocaine) may provide temporary relief

  • Chronic fissures may be treated with

    • Topical 0.125–0.4% nitroglycerin or diltiazem 2% or nifedipine 0.5% ointment (1 cm of ointment) applied two or three times daily just inside anus with tip of finger for 4–8 weeks

    • Injection of botulinum toxin (20 units) into internal anal sphincter

    • These treatments result in healing in 60–90% of patients with chronic anal fissure, but headaches occur in up to 40% of patients treated with nitroglycerin

  • Botulinum toxin may cause transient anal incontinence

  • Internal sphincterotomy is effective for chronic or recurrent fissures but may be complicated by minor fecal incontinence

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