What is the best course of treatment for an anal fissure?

Treatment of Anal Fissure

Start with conservative management including increased fiber and water intake, combined with topical anesthetics for pain control—this approach heals approximately 50% of acute fissures within 10-14 days and should be the first-line treatment for all patients. 1, 2, 3

Initial Conservative Management (First 2 Weeks)

• Dietary modifications are the cornerstone: increase fiber intake through diet or supplements to soften stools 1, 2, 3
• Adequate water consumption is essential to prevent constipation and promote healing 1, 2, 3
• Topical anesthetics (such as lidocaine) should be applied directly to the fissure for immediate pain relief 1, 2
• Oral analgesics (such as paracetamol) can be added if topical agents provide inadequate pain control 1, 2
• Warm sitz baths promote sphincter relaxation and should be used regularly 2, 3
• Pain relief typically occurs within 14 days of appropriate treatment 2, 3

Escalation to Topical Pharmacotherapy (After 2 Weeks if No Improvement)

If conservative measures fail after 2 weeks, add topical calcium channel blockers—specifically 0.3% nifedipine with 1.5% lidocaine applied three times daily for at least 6 weeks, which achieves 65-95% healing rates. 4, 3

• Topical calcium channel blockers work by blocking calcium channels in vascular smooth muscle, reducing internal anal sphincter tone and increasing blood flow to the ischemic ulcer 3
• This is superior to nitroglycerin ointment, which has lower healing rates (25-50%) and causes frequent headaches 4, 3
• Continue treatment for the full 6-week course even if symptoms improve earlier 3

Surgical or Botulinum Toxin Intervention (After 8 Weeks if Still Not Healed)

Reserve surgery or botulinum toxin injection for chronic fissures that fail 8 weeks of comprehensive non-operative management—lateral internal sphincterotomy is the gold standard surgical procedure with >95% healing rates. 1, 4, 3

• Botulinum toxin injection achieves 75-95% healing rates with no risk of permanent incontinence and should be strongly considered for patients with compromised sphincter function or risk factors for incontinence 4, 5
• Lateral internal sphincterotomy remains the most effective long-term treatment with healing rates exceeding 95% and recurrence rates of only 1-3% 3, 5, 6
• Surgery should never be performed for acute fissures 1, 2

Critical Pitfalls to Avoid

• Never perform manual dilatation—this causes high rates of temporary and permanent incontinence and is strongly contraindicated 1, 4, 2, 3
• Do not skip the 8-week trial of conservative and topical therapy before considering botulinum toxin or surgery 4
• Evaluate atypical features carefully: lateral location (rather than posterior midline), multiple fissures, or failure to heal require investigation for Crohn's disease, inflammatory bowel disease, or malignancy 4, 2, 3
• Do not use botulinum toxin in acute fissures that have not failed conservative management 4

When to Investigate Further

• For typical acute fissures presenting in the posterior midline, clinical examination alone is sufficient—no routine laboratory or imaging studies are needed 1, 2
• For atypical fissures, perform focused history and physical examination, and consider endoscopy, CT, MRI, or endoanal ultrasound to rule out inflammatory bowel disease, anal cancer, or occult perianal sepsis 1, 2