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Anal fissures are frequent, simple to diagnose, and often overlooked. A fissure is a longitudinal tear/wound/ulceration between the dentate line and the anal verge, typically located in the midline, associated with high anal sphincter tone. Risk factors: constipation, chronic diarrhea (idiopathic, IBD, post–gastric bypass), but fissure may also occur with normal bowel movements.

  • • Acute fissure is defined as new onset, no signs of chronicity, typically related to identifiable acute episode of constipation or diarrhea.
  • • Chronic fissure is defined as either > 3 months of symptoms or morphologic signs of chronicity (elevated/indurated wound edges, exposed sphincter muscle, sentinel skin tag, hypertrophic anal papilla).

Complications are rare: development of a perirectal fistula/abscess, chronic pain (even if fissure healed), ie, anismus.

Pathophysiology: acute or chronic stress/trauma to the anal canal (constipation, diarrhea) results in superficial tear; acute fissure will heal in 40–60% with appropriate improved stool management, or may turn into chronic anal fissure and result in a vicious circle: increasing sphincter tone, hypertonicity of internal anal sphincter muscle (resting tone) → fissure hiding between anal canal folding such that it cannot clean out → pain → increased sphincter spasm → etc.

Treatment of fissure aims at normalizing stool regularity and decreasing sphincter tone.


Exact prevalence and incidence are unknown (referral bias); in a specialist clinic, 3–5% of patients have a fissure as presenting symptom. More common in young and middle-aged adult patients; most frequent cause of rectal bleeding in children.


Patients often present with “painful hemorrhoids” as they feel the sentinel skin tag and notice the pain during and after bowel movements.

Pain: typically post defecation, varying degrees, ranging from mild itching to discomfort to massive excruciating pain periods. But an estimated 10% of patients do not complain of pain, or they just have pruritus or mild discomfort.

Duration of pain: typically during and post bowel movements, occasionally several hours thereafter, or permanent/constant pain.

Bleeding: acute fissure—sometimes significant bright red bleeding; chronic fissure—more often just traces of blood on toilet paper. Severe hemorrhage or anemia unlikely related to fissure.

Lump: “irritated” external hemorrhoids (sentinel skin tag), but absence of dynamic protrusion during bowel movement.

Differential Diagnosis

Pain: thrombosed external hemorrhoid, abscess, levator ani spasm, anismus.

HIV-associated ulcer: HIV infection+; ulceration: often in the same location and/or eccentric; sphincter tone typically not increased, or even decreased.

Crohn disease: anal symptoms may be the only manifestation or be associated with other signs/locations of active Crohn disease.

STDs: syphilis, herpes.

Perirectal fistula/abscess: particularly horseshoe fistula characteristically originates from posterior midline.

Tuberculosis: clinical suspicion, atypical presentation, associated pulmonary symptoms, positive PPD ...

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