What is the first-line treatment for an adult with an acute or chronic anal fissure?

First-Line Treatment for Anal Fissure

For acute anal fissures, start with conservative management including 25-30g daily fiber supplementation, adequate hydration, and warm sitz baths 2-3 times daily, which heals approximately 50% of cases within 10-14 days. 1, 2 If the fissure persists beyond 2 weeks or is chronic (>8 weeks), add compounded 0.3% nifedipine with 1.5% lidocaine applied three times daily for at least 6 weeks, achieving 95% healing rates. 1, 2

Initial Assessment

Before initiating any treatment, verify the fissure location by effacing the anal canal with opposing traction on the buttocks. 1

• Typical fissures occur in the posterior midline in 90% of cases; anterior fissures occur in 10% of women versus 1% of men. 1
• Atypical locations (lateral, off-midline, or multiple fissures) require urgent evaluation for Crohn's disease, HIV/AIDS, ulcerative colitis, tuberculosis, syphilis, herpes, anorectal cancer, or malignancy before starting any therapy. 1, 3

Conservative Management (First-Line for All Acute Fissures)

This approach heals approximately 50% of acute anal fissures within 10-14 days and should be attempted in all patients before pharmacologic therapy. 1, 2

• Fiber supplementation: Increase intake to 25-30g daily through diet or supplements to soften stools and minimize anal trauma. 1, 2
• Adequate hydration: Maintain sufficient fluid intake throughout the day to prevent constipation. 1, 2
• Warm sitz baths: Perform 2-3 times daily to promote internal anal sphincter relaxation. 1, 2
• Topical analgesics: Apply lidocaine 5% for pain control as needed. 1

Pharmacologic Therapy (Second-Line)

If the fissure persists after 2 weeks of conservative care, or for chronic fissures (>8 weeks), add topical calcium channel blocker therapy. 1, 2

Preferred Option: Compounded Nifedipine with Lidocaine

• Formulation: 0.3% nifedipine with 1.5% lidocaine applied three times daily for at least 6 weeks. 1, 2, 4
• Healing rate: 95% after 6 weeks of treatment. 1, 2, 4
• Pain relief: Typically occurs after 14 days of treatment. 2, 4
• Mechanism: Nifedipine blocks slow L-type calcium channels in vascular smooth muscle, reducing internal anal sphincter tone and increasing local blood flow to the ischemic ulcer; lidocaine provides local anesthesia and breaks the pain-spasm-ischemia cycle. 2, 4

Alternative Option: Diltiazem 2% Cream

• Application: Apply to the anal verge twice daily for 8 weeks. 1
• Healing rate: 48-75% without the headache side effects associated with nitroglycerin. 1
• Consider if: Nifedipine is unavailable or patient prefers twice-daily dosing. 1

Less Preferred Option: Topical Nitroglycerin (GTN)

• Healing rate: Only 25-50%, significantly lower than calcium channel blockers. 1
• Side effects: Causes headaches in many patients, though these rarely require cessation of therapy. 1, 3
• Recommendation: Not first-line due to inferior efficacy and side effect profile. 1

Critical Pitfalls to Avoid

• Manual anal dilatation is absolutely contraindicated due to permanent fecal incontinence rates of 10-30%. 1, 2, 4
• Hydrocortisone should not be used beyond 7 days due to risk of perianal skin thinning and atrophy, which can worsen the fissure. 1, 2, 4
• Never rush to surgery for acute fissures, as 50% heal with conservative management alone. 1

Surgical Intervention (Third-Line)

Lateral internal sphincterotomy (LIS) should be considered only after 6-8 weeks of failed comprehensive medical therapy (fiber, hydration, sitz baths, and topical calcium channel blocker), or for acute fissures with severe, intractable pain that makes conservative care intolerable. 1, 2

LIS Outcomes

• Healing rate: >95% with recurrence in only 1-3% of cases. 1, 5, 3, 6
• Risk: Small risk of minor permanent incontinence (typically flatus incontinence) in 1-10% of patients, significantly lower than the 10-30% risk with manual dilatation. 1
• Technique: Perform laterally (at 3 or 9 o'clock position) with division extending to the dentate line. 1

Contraindications to LIS

• Pre-existing fecal incontinence or weakened sphincter function. 1
• Women with anterior fissures (higher incontinence risk). 1
• Patients with Crohn's disease or inflammatory bowel disease. 1

Alternative to LIS: Botulinum Toxin Injection

• Healing rate: 75-95% with low morbidity. 1, 5, 3
• Indication: Sphincter-sparing option for patients unsuitable for LIS or those at high risk for incontinence. 1, 5
• Side effects: Minor transitory incontinence for flatus and soiling in up to 12% of patients. 3

Treatment Algorithm

1. Verify typical posterior-midline location; if atypical, halt treatment and evaluate for underlying disease. 1
2. Initiate conservative management (fiber 25-30g/day, adequate fluids, sitz baths 2-3×/day, topical lidocaine). 1, 2
3. Reassess at 2 weeks; if no improvement, add compounded 0.3% nifedipine + 1.5% lidocaine three times daily. 1, 2
4. Continue pharmacologic therapy for 6-8 weeks total. 1, 2
5. If unhealed after 6-8 weeks of comprehensive medical therapy, refer for lateral internal sphincterotomy. 1, 2

Special Populations

• Pregnancy: Prioritize conservative measures (fiber, hydration, sitz baths); topical calcium channel blockers may be used after obstetric consultation. 1
• Children: First-line treatment is the same conservative regimen; surgical intervention is reserved for truly refractory cases after prolonged medical therapy to minimize incontinence risk. 1