Type your tag names separated by a space and hit enter

Anal Fissure

Anal Fissure is a topic covered in the 5-Minute Clinical Consult.

To view the entire topic, please or purchase a subscription.

Medicine Central™ is a quick-consult mobile and web resource that includes diagnosis, treatment, medications, and follow-up information on over 700 diseases and disorders, providing fast answers—anytime, anywhere. Explore these free sample topics:

Medicine Central

-- The first section of this topic is shown below --



Anal fissure (fissure in ano): longitudinal tear in the lining of the anal canal distal to the dentate line, most commonly at the posterior midline; characterized by a knifelike tearing sensation on defecation, often associated with bright red blood per rectum. This common benign anorectal condition is often confused with hemorrhoids; may be acute (<8 weeks) or chronic (>8 weeks) in duration


  • Affects all ages. Common in infants 6 to 24 months; not common in older children, suspect abuse, or trauma; elderly less common due to lower resting pressure in the anal canal
  • Sex: male = female; women more likely to get anterior midline fissures (25%) versus men (8%)

Exact incidence is unknown (1). Patients often treat with home remedies and do not seek medical care.

  • 80% of infants, usually self-limited
  • 10–20% of adults, most of whom do not seek medical advice.
  • Lateral fissure: Rule out infectious disease.
  • Atypical fissure: Rule out Crohn disease.

Etiology and Pathophysiology

High-resting pressure within the anal canal (usually as a result of constipation/straining) leads to ischemia of the anoderm, resulting in splitting of the anal mucosa during defecation and spasm of the exposed internal sphincter.

None known

Risk Factors

  • Constipation (25% of patients)
  • Diarrhea (6% of patients)
  • Passage of hard or large-caliber stool
  • High-resting pressure of internal anal sphincter (prolonged sitting, obesity)
  • Trauma (sexual activity or abuse, foreign body, childbirth, mountain biking)
  • Prior anal surgery with scarring/stenosis
  • Inflammatory bowel disease (Crohn disease)
  • Infection (chlamydia, syphilis, herpes, tuberculosis)

General Prevention

All measures to prevent constipation; avoid straining and prolonged sitting on toilet.

Commonly Associated Conditions

Constipation, irritable bowel syndrome, Crohn disease, tuberculosis, leukemia, and HIV

-- To view the remaining sections of this topic, please or purchase a subscription --


Stephens, Mark B., et al., editors. "Anal Fissure." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2019. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116021/0.4/Anal_Fissure.
Anal Fissure. In: Stephens MB, Golding J, Baldor RA, et al, eds. 5-Minute Clinical Consult. 27th ed. Wolters Kluwer; 2019. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116021/0.4/Anal_Fissure. Accessed July 15, 2019.
Anal Fissure. (2019). In Stephens, M. B., Golding, J., Baldor, R. A., & Domino, F. J. (Eds.), 5-Minute Clinical Consult. Available from https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116021/0.4/Anal_Fissure
Anal Fissure [Internet]. In: Stephens MB, Golding J, Baldor RA, Domino FJ, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2019. [cited 2019 July 15]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116021/0.4/Anal_Fissure.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Anal Fissure ID - 116021 ED - Stephens,Mark B, ED - Golding,Jeremy, ED - Baldor,Robert A, ED - Domino,Frank J, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116021/0.4/Anal_Fissure PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -