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Anal Fissure
Anne Walsh, MMSc, PA-C, DFAAPA
Kashyap Trivedi, MD
image BASICS
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 very common benign anorectal condition is often confused with hemorrhoids. May be acute (<6 weeks) or chronic (>6 weeks) in duration
  • Affects all ages. Common in infants 6 to 24 months; not common in older children, suspect abuse, or trauma. Elderly is less common due to lower resting pressure in the anal canal.
  • Sex: male = female; women are more likely to get anterior midline tears (25% vs. 8%).
Exact incidence is unknown. Patients often treat with home remedies and do not seek medical care.
  • 80% of infants, usually self-limited
  • 20% of adults, most of whom do not seek medical advice
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
  • Constipation (25% of patients)
  • Diarrhea (6% of patients)
  • Passage of hard or large-caliber stool
  • High-resting of internal anal sphincter (prolonged sitting, obesity)
  • Trauma (sexual abuse, childbirth, mountain biking)
  • Inflammatory bowel disease (Crohn disease)
  • Infection (chlamydia, syphilis, herpes, tuberculosis)
All measures to prevent constipation; avoid straining and prolonged sitting on toilet.
Constipation, irritable bowel syndrome, Crohn disease, tuberculosis, leukemia, and HIV
  • Gentle spreading of the buttocks with close inspection of the anal verge will reveal a smooth-edged tear in the anodermal tissue, typically posterior midline, occasionally anterior midline, rarely eccentric to midline.
  • Minimal edema, erythema, or bleeding may be seen.
  • Chronic fissures may demonstrate rolled edges, hypertrophic papillae at proximal end, and a sentinel pile (tag) at distal end.
  • Thrombosed external hemorrhoid: swollen, painful mass at anal verge
  • Perirectal abscess: tender, warm erythematous induration or fluctuance
  • Perianal fistula: abnormal communication between rectum and perianal epithelium with purulent drainage
  • Pruritus ani: shallow excoriations rather than true fissure
Diagnostic Procedures/Other
  • Avoid anoscopy/sigmoidoscopy initially unless necessary for other diagnoses.
  • Rarely, due to pain, some patients may require exam under anesthesia in order to confirm the diagnosis.
The goal of treatment is to avoid repeated tearing of the anal mucosa with resultant spasm of the internal anal sphincter by decreasing the patient's high sphincter tone and addressing its underlying cause.
  • Wash area gently with warm water; consume highfiber diet, increase fluids, add daily fiber supplement; avoid constipation, maintain healthy weight.
  • Medical therapy for chronic fissures usually initiated in a stepwise manner: nitrates, calcium channel blockers, botulinum toxin (1)[B]
First Line
Acute fissures—50% heal spontaneously with supportive measures:
  • Stool softeners (docusate) daily
  • Osmotic laxatives if needed (polyethylene glycol)
  • Fiber supplements (e.g., psyllium, methylcellulose, inulin) and increased fluid intake
  • Topical analgesics (2% lidocaine gel)
  • Topical lubricants/emollients (Balneol cream)
  • Sitz baths (sit in hot water bath for 10 to 20 minutes 2 to 3 times daily)
Second Line
Chronic fissures—require medical therapy (1,2)[A]:
  • Chemical sphincterotomy
    • Topical nitroglycerin ointment 2% diluted to 0.2-0.4% applied QID; nitroglycerin 0.4% ointment available commercially (Rectiv): marginally but significantly better than placebo in healing (48.6% vs. 37%); late recurrence common (50%) (1)[A]; effect is to reduce resting anal pressure through the release of nitric oxide. Headache is a major side effect (20-30%).
    • Calcium channel blockers (e.g., nifedipine, diltiazem), oral or topical: no better than nitrates but with fewer side effects; effect is to relax the internal sphincter muscle, thereby reducing the resting anal pressure (3)[A].
    • Botulinum toxin 4 mL (20 units) injected into the internal sphincter muscle: no better than topical nitrates but with fewer side effects; effect is to inhibit the release of acetylcholine from nerve endings to inhibit muscle spasm (4)[B].

  • Late recurrence is common (50%) particularly if the underlying issue remains untreated (constipation, irritable bowel, etc.).
  • Medical therapy usually is tried for 90 to 120 days prior to colorectal surgery referral.
Anococcygeal support (modified toilet seat) may offer some advantage in chronic fissures to avoid surgery.
  • Surgery reserved for failure of medical therapy; involves division of the internal sphincter muscle
  • Lateral internal sphincterectomy is the surgical procedure of choice (90% healing) (5)[A].
    • Risk for fecal or flatus incontinence: 45% short term, 6-8% long term
  • Botulinum toxin injections also first-line treatment; less effective (60-80% healing) than surgery but fewer complications (6)[C]
    • Risk for fecal or flatus incontinence: 18% short term, no long term
    • May be repeated as needed with same efficacy; higher doses are more effective.
  • Controlled pneumatic balloon dilation may be used by gastroenterologists if surgical referral is not available; should not be used first line as benefits are not well documented. Uncontrolled manual dilation is no longer recommended (5,6)[C].
High fiber (>25 g/day; augment with daily fiber supplements); increase fluid intake.
  • Avoid prolonged sitting or straining during bowel movements; drink plenty of fluids; avoid constipation; lose weight if obese.
  • Avoid use of triple antibiotic ointment and longterm use of steroid creams to anal area.
Most acute fissures heal within 6 weeks with conservative therapy. Medical therapy is less likely to be successful for chronic anal fissures; 40% failure rate.
1. Altomare DF, Binda GA, Canuti S, et al. The management of patients with primary chronic anal fissure: a position paper. Tech Coloproctol. 2011;15(2):135-141.
2. Nelson RL, Thomas K, Morgan J, et al. Non surgical therapy for anal fissure. Cochrane Database Syst Rev. 2012;(2):CD003431.
3. Samim M, Twigt B, Stoker L, et al. Topical diltiazem cream versus botulinum toxin a for the treatment of chronic anal fissure: a double-blind randomized clinical trial. Ann Surg. 2012;255(1):18-22.
4. Madalinski MH. Identifying the best therapy for chronic anal fissure. World J Gastrointest Pharmacol Ther. 2011;2(2):9-16.
5. Nelson RL, Chattopadhyay A, Brooks W, et al. Operative procedures for fissure in ano. Cochrane Database Syst Rev. 2011;(11):CD002199.
6. Wald A, Bharucha AE, Cosman BC, et al. ACG clinical guideline: management of benign anorectal disorders. Am J Gastroenterol. 2014;109(8):1141-1157.
Additional Reading
  • Fargo MV, Latimer KM. Evaluation and management of common anorectal conditions. Am Fam Physician. 2012;85(6):624-630.
  • Gee T, Hisham RB, Jabar MF, et al. Ano-coccygeal support in the treatment of idiopathic chronic posterior anal fissure: a prospective non-randomised controlled pilot trial. Tech Coloproctol. 2013; 17(2):181-186.
  • Sinha R, Kaiser AM. Efficacy of management algorithm for reducing need for sphincterotomy in chronic anal fissures. Colorectal Dis. 2012;14(6): 760-764.
  • Sugerman DT. JAMA patient page. Anal fissure. JAMA. 2014;311(11):1171.
  • Yiannakopoulou E. Botulinum toxin and anal fissure: efficacy and safety systematic review. Int J Colorectal Dis. 2012;27(1):1-9.
  • K60.2 Anal fissure, unspecified
  • K60.0 Acute anal fissure
  • K60.1 Chronic anal fissure
Clinical Pearls
  • Avoid anoscopy or sigmoidoscopy initially unless necessary for other diagnoses.
  • Best chance to prevent recurrence is to treat the underlying cause (e.g., chronic constipation).
  • No medical therapy approaches the cure rate of surgery for chronic fissure.