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Anal Fissure


An anal fissure is a cut or tear in the lining of the anus. The anus is the opening through which stool leaves the body.

Anal Fissure
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The exact cause is not known. In most people, it happens as a result of trauma to the anal lining. Trauma can be caused by:

  • A large, dry, or hard stool (poop)
  • Frequent diarrhea
  • Tightened anal sphincter, a group of muscles that open and close the anus
  • Childbirth
  • Receiving anal intercourse
  • Sexual abuse in children

Risk Factors

Anal fissures are most common in middle-aged adults. But they can happen at any age. Things that may raise the risk of this problem are:

  • Constipation
  • Diarrhea
  • Pregnancy with vaginal delivery
  • Receiving anal intercourse
  • Sexual abuse in children
  • Colonoscopy
  • Diets low in fiber, high in processed meat and white bread


Symptoms are severe burning or tearing pain during and after passing stool (poop). A person may also pass bright red blood or mucous.


The doctor will ask about symptoms and past health. A physical exam will be done. It will focus on the anus. The doctor will likely be able to see an anal fissure. This is enough to make the diagnosis.

If the diagnosis is not clear, these tests may be done:

  • Digital rectal exam—to feel for any lumps or abnormalities
  • Anoscopy—to look at the anal canal with a scope
  • MRI scan or CT scan


The goal of treatment is to promote healing. Options are:

  • Self care, such as warm sitz baths and increasing fiber and fluids
  • Medicines, such as:
    • Stool softeners or laxatives
    • Topical anesthetic to ease pain
    • Topical steroid cream to ease swelling
    • Topical nitrates and calcium channel blockers to increase blood flow and ease pain
    • Injected botulinum toxin to relax tightened muscles

People who are not helped by these methods may need surgery. Options are:

  • Lateral internal sphincterotomy —Making a tiny incision in the sphincter muscle fibers to prevent spasms that result in straining during a bowel movement
  • Fissurectomy—Removing the fissure
  • Anal advancement flap—Covering the fissure with tissue from another part of the body
  • Anal dilation—Widening and stretching the anal canal (rare)


The risk of this problem may be lowered by:

  • Eating a high fiber diet
  • Drinking plenty of fluids


  • Anal fissure. American Society of Colon and Rectal Surgeons website. Available at: https://fascrs.org/patients/diseases-and-conditions/a-z/anal-fissure.
  • Anal fissure. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/anal-fissure.
  • Boland PA, Kelly ME, et al. Management options for chronic anal fissure: a systematic review of randomised controlled trials. Int J Colorectal Dis. 2020;35(10):1807-1815.