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Anal Fissure: Causes, Treatment and Prevention

Anal fissure is an ulcer (open sore) or a tear in the lining of the anus. The last part of the large intestine where it ends is known as the anal canal, and it opens to the outside through the opening called the anus.

Anal Fissure: Causes, Treatment and Prevention


Injury: The main cause of anal fissure is an injury to the internal lining of the anus or anal canal.

Constipation: Anal fissure is most commonly seen in people with constipation when a hard or large stool tears the lining of the anal canal.

Risk Factors

The risk factors associated with anal fissure include:

  • Dietary factors. Consuming diets low in fibre and water, increase the risk of constipation. Some foods such as caffeine may increase the risk of straining during defecation. Spicy foods are known to increase the symptoms of anal fissures.
  • Persistent diarrhoea
  • Inflammatory bowel disease (IBD) – such as Crohn’s disease and Ulcerative colitis
  • Pregnancy and childbirth. There is an increased incidence of anal fissures during pregnancy and childbirth.
  • Tight anal sphincter. The muscles of anal sphincter are abnormally tight in some individuals making them more vulnerable to tear.
  • Sexually transmitted infections (STIs). Occasionally, the cause may be STIs such as syphilis or herpes causing damage to the anal canal.
  • Other causes. Rough toilet paper, longstanding moistness around the anus, constant mountain biking and anal sex.
  • In infants. Early introduction of cow’s milk, inadequate fluid intake, infrequent diaper changes and constipation.


  • Pain when you pass stools: Pain is present both in acute and chronic anal fissures. In the acute stage, severe pain is experienced during defecation. In chronic anal fissure, there may be sharp pain during defecation followed by deep burning pain that may persist for several hours.
  • Tears/cut: Visible tears/cut in the area.
  • Bleeding when you pass stools: A small amount of blood (bright red) may be noted in the stools or on the tissue paper.


Your doctor will be able to make a diagnosis of anal fissures based on the symptoms (pain and bleeding associated with defecation) and rectal examination.

Rectal Examination. A gloved and lubricated finger is inserted into the anal canal after applying a local anaesthetic to relax the sphincter. Sometimes an instrument called anoscope may be inserted to get a better visibility of anus and anal canal. The lining of the anal canal is examined for the fissure.

Colonoscopy or Flexible Sigmoidoscopy. A flexible tube with a camera at its terminal part is inserted through the anus, to visualise the lower part of the large intestine (sigmoid colon) or the entire colon (colonoscopy).

Anal manometry. A thin, flexible tube is inserted into the anus and rectum. A balloon is expanded to test for the function of the rectum and tightness of the anal sphincter.

Anal Fissure: Causes, Treatment and Prevention


An acute anal fissure will heal in 6 weeks with conservative measures and when constipation is treated. Fissures that persist beyond six weeks are called as chronic anal fissures and they need aggressive surgical approaches.

Conservative treatment

  • Increasing the fibre content and water in your diet can reduce constipation and hardness of stools.
  • Taking stool softeners on an as needed basis to make stools softer will make passage of stools easier.
  • Sitting in a tub of warm water (called as Sitz bath) to soak the anus and rectal area for 10 to 15 minutes can relax the sphincter and promote healing.
  • The doctor may prescribe topical anaesthetic medications such as lidocaine for temporary relief of pain.
  • Topical medications such as nitrates or calcium blockers may be prescribed to make the anal sphincter relax.

Surgical options

These methods are now commonly performed as outpatient or day care procedures. The aim of these procedures is to promote the relaxation of the anal sphincter, which will reduce the anal pain and spasm to allow fissure healing.

Botulinum toxin type A (Botox) injection – A chemical substance is injected into the anal sphincter to paralyse it and relax the spasms.

Lateral internal sphincterotomy – A minor operative procedure where a small part of the anal sphincter muscle is cut to relax the sphincter and facilitate healing of the fissure.


  • Avoid constipation by drinking plenty of fluids and taking a high fibre diet
  • Avoid straining during defecation
  • Avoid prolonged diarrhoea
  • Avoid chronic wetness around the anus
  • Avoid rough toilet papers or other harsh types of anal hygiene products or methods
  • In infants, ensure adequate fluid intake with water added to formulas and frequent diaper changes.
  • When a fissure is suspected, a lubricating ointment can be used to prevent further worsening.


  • Non-healing fissure. An anal fissure that does not heal in few weeks become chronic and extend into deeper layers. When the ulcer extends to the internal anal sphincter muscle, there can be muscle spasms which will impair the blood supply to the fissure.
  • Abscess formation. Infection of the fissure by bacteria can cause abscess formation.
  • Bleeding. When a blood vessel is involved in the ulcer, bleeding from the anal fissure can occur.
  • Recurrence. Once a person has an anal fissure, they are predisposed to have another one.
  • Anal cancer. Some research studies have indicated that inflammatory conditions of the anus (such as anal fissure with chronic infection) can increase the risk of anal cancer.

Next Steps

If you experience pain during passing stools or notice blood while passing the stools or on toilet paper, visit a doctor for further evaluation.

Red Flags

Along with pain and bleeding during defecation, if you have other symptoms such as a change in bowel habit (increased frequency or diarrhoea), passing fleshy masses in stools, weight loss, mass in the abdomen and easy fatigability, share this information with the doctor immediately. These may be symptoms of other serious conditions, such as inflammatory bowel diseases or cancer.

Consult a top Proctologist

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  • University Hospitals Case medical center. Anal Fissure. Accessed at http://www.uhhospitals.org/case/services/surgery/our-divisions/colorectal-surgery/anal-fissure on 15 June 2016.
  • The Johns Hopkins University. Anal Fissures. Accessed at http://www.hopkinsmedicine.org/healthlibrary/conditions/digestive_disorders/anal_fissures_134,174/ on 16 June 2016.
  • NHS choices. Anal fissure. Anal fissure. Accessed at http://www.nhs.uk/Conditions/Anal-fissure/Pages/Introduction.aspx on 15 June 2016.

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