What is an anal fissure?
Anal fissure is a linear split in the mucosa of the anal canal, most commonly in the posterior midline. Although small in size, it causes disproportionately severe pain during and after defecation, due to the rich innervation of the area and persistent spasm of the internal sphincter.
It is classified as acute (duration <6 weeks) and chronic (duration >6 weeks, with visible secondary changes). Modern treatment aims to relax the sphincter and heal the fissure.
How common is it?
Anal fissure is one of the most common causes of anal pain. It is estimated that 10% of the population will experience an episode of anal fissure during their lifetime. It affects men and women equally, with peak incidence between 30 and 50 years.
After childbirth, the appearance of fissure in women is particularly frequent. It is often confused with hemorrhoids or thrombosed external hemorrhoid.
How does it present?
The main symptoms of anal fissure include:
- Intense, "tearing" pain during defecation that lasts minutes to hours afterwards.
- Bright red bleeding on toilet paper or on the surface of the stool.
- Internal sphincter spasm — feeling of tightness.
- Avoidance of defecation due to fear of pain, leading to constipation.
- Possible itching or burning sensation.
- In chronic fissures: presence of a "sentinel pile" externally.
How is it diagnosed?
Diagnosis is usually clinical:
- Inspection of the perianal area with gentle separation of the buttocks.
- Digital rectal examination is usually avoided in the acute phase due to pain.
- Proctoscopy after treatment or under local anesthesia.
- In atypical location (non-midline, multiple fissures): investigation for IBD, sexually transmitted infections, leukemia.
Which factors increase risk?
There is no specific genetic predisposition. Important risk factors relate to bowel function and sphincter tone.
- Chronic constipation or hard stools.
- Episodes of diarrhea.
- Childbirth (often posterior fissure after vaginal delivery).
- Anal intercourse — often anterior fissure.
- High internal sphincter tone.
- Inflammatory bowel disease (Crohn's disease).
Modern therapeutic options
The choice of the appropriate technique is individualised for each patient, based on disease stage, anatomy, comorbidities and patient preference.
Conservative Treatment (1st line)
Success rate >50–70% in acute fissures. Includes increased fibre and fluid intake, mild laxatives, sitz baths in warm water 2–3 times daily, topical creams with nitrates (GTN 0.2%) or calcium channel blockers (Diltiazem 2%) that relax the internal sphincter.
Botulinum Toxin Injection (Botox)
For chronic fissures that do not heal with conservative treatment. A small amount of Botox relaxes the sphincter for 2–3 months, allowing healing. Success rate 60–80%, without risk of permanent continence disturbance.
Lateral Internal Sphincterotomy (LIS)
The gold standard surgical technique, with success rates >95% in chronic refractory fissures. A small incision is made in the lateral part of the internal sphincter. Rare mild incontinence. A modern variant is tailored sphincterotomy with reduced incontinence risk.
Frequently asked questions
Is it a fissure or a hemorrhoid?
They are often confused. A fissure causes severe pain during defecation. Hemorrhoids are rarely painful (except when thrombosed) and cause bleeding or prolapse. A proper examination by a specialist easily distinguishes between them.
Will I need surgery?
Only in ~10–20% of cases. The vast majority of acute fissures heal with conservative treatment. In chronic cases, topical toxin often avoids surgery.
Can it come back?
Yes, particularly if the original cause returns (constipation, hard stools). Long-term management includes stable bowel regulation.