What is the recommended medical management for an anal fissure?

Medical Management of Anal Fissure

For acute anal fissures, begin with conservative management (fiber 25–30 g/day, adequate hydration, warm sitz baths 2–3 times daily, and topical lidocaine for pain), and if no improvement occurs after 2 weeks, add compounded topical nifedipine 0.3% with lidocaine 1.5% applied three times daily for 6–8 weeks, which achieves 95% healing rates. 1, 2

Initial Assessment and Red Flags

Before initiating any therapy, verify that the fissure is located in the posterior midline (90% of cases) or anterior midline (10% of women, 1% of men). 1, 2

Critical red flags requiring urgent evaluation before treatment:

• Lateral or off-midline fissure location – mandates workup for Crohn's disease, HIV/AIDS, ulcerative colitis, tuberculosis, syphilis, leukemia, or malignancy 1, 2
• Multiple fissures – suggests underlying inflammatory or infectious disease 1
• Rectal bleeding with anemia or unexplained weight loss – requires colonoscopy to exclude colorectal cancer 1

The diagnosis is clinical: acute stinging pain during and immediately after defecation (not constant), with bright red blood on toilet paper. 1, 2 Visualize the fissure by separating the buttocks with opposing traction to evert the anal canal; do not instrument the canal if pain is severe. 2

First-Line Conservative Management (All Acute Fissures)

Approximately 50% of acute fissures heal within 10–14 days with this regimen alone. 1, 2, 3

Specific conservative measures:

• Fiber supplementation: Increase to 25–30 g daily via diet or supplements to soften stools and minimize anal trauma 1, 2, 3
• Adequate hydration: Maintain throughout the day to prevent constipation 1, 2
• Warm sitz baths: Perform 2–3 times daily to promote internal anal sphincter relaxation 1, 2, 3
• Topical lidocaine 5%: Apply for pain control, which helps break the pain-spasm-ischemia cycle 1, 3

Second-Line Pharmacologic Therapy (After 2 Weeks Without Improvement)

Preferred Option: Topical Calcium Channel Blocker

Compounded nifedipine 0.3% with lidocaine 1.5% applied three times daily for at least 6 weeks is the preferred pharmacologic option, achieving 95% healing rates with pain relief typically evident after 14 days. 1, 2, 3

Mechanism: Nifedipine blocks L-type calcium channels in internal anal sphincter smooth muscle, reducing sphincter tone and increasing local blood flow to the ischemic fissure. 1, 2 The internal anal sphincter (not the external sphincter) generates the pathologic hypertonia, with resting pressures averaging 114 ± 17 cm H₂O in fissure patients versus 73 ± 27 cm H₂O in normal individuals. 1

Alternative calcium channel blocker: Diltiazem 2% cream applied twice daily for 8 weeks achieves 48–75% healing rates with minimal side effects. 1, 3 Diltiazem shows similar efficacy to nifedipine and is better tolerated than nitroglycerin. 1, 3

Less Preferred Option: Topical Nitroglycerin

Topical nitroglycerin (GTN) achieves only 25–50% healing rates and causes frequent headaches in many patients, making it a less preferred option despite its availability. 1, 2, 3, 4 The headaches rarely require cessation of therapy, but the lower efficacy compared to calcium channel blockers makes GTN second-line. 1

Third-Line: Botulinum Toxin Injection

If topical calcium channel blockers fail after 6–8 weeks, botulinum toxin injection into the internal anal sphincter demonstrates 75–95% cure rates with low morbidity. 1, 2, 3 This is a sphincter-sparing option that causes temporary sphincter relaxation without the permanent incontinence risk of surgery. 1, 5

Surgical Management: Lateral Internal Sphincterotomy (LIS)

Indications for LIS:

• Chronic fissures (>8 weeks duration) that have failed documented 6–8 weeks of comprehensive medical therapy (fiber, hydration, sitz baths, and topical calcium channel blocker) 1, 2, 3
• Acute fissures with severe, intractable pain that makes conservative care intolerable 1

Outcomes: LIS achieves >95% healing rates with only 1–3% recurrence over long-term follow-up. 1, 2, 5, 4

Risks: Minor permanent continence defects (typically flatus incontinence) occur in approximately 1–10% of patients, markedly lower than the 10–30% incontinence risk with manual dilation. 1, 6, 5

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

Absolute Contraindications in Fissure Management

Manual anal dilatation is absolutely contraindicated due to 10–30% permanent incontinence rates from uncontrolled sphincter injury. 1, 2, 3, 6 This procedure should never be performed under any circumstances. 1

Hydrocortisone should not be used beyond 7 days due to risk of perianal skin thinning and atrophy, which can worsen the fissure. 1, 2

Coconut oil is ineffective – it provides only superficial lubrication without pharmacologic action to reduce sphincter tone or increase blood flow. 1, 2

Treatment Algorithm Summary

Step 1: Verify typical posterior-midline location; if atypical, halt treatment and evaluate for underlying disease. 1, 2

Step 2: Initiate conservative management (fiber 25–30 g/day, adequate fluids, sitz baths 2–3×/day, topical lidocaine). 1, 2, 3

Step 3: Reassess at 2 weeks; if no improvement, add compounded nifedipine 0.3% + lidocaine 1.5% three times daily. 1, 2

Step 4: Continue pharmacologic therapy for a total of 6–8 weeks. 1, 2

Step 5: If unhealed after 6–8 weeks of comprehensive medical therapy, consider botulinum toxin injection or refer for lateral internal sphincterotomy. 1, 2, 3

Special Populations

Pregnancy: Prioritize conservative measures (fiber, hydration, sitz baths); topical calcium channel blockers may be used after obstetric consultation. 1

Children: Use the same conservative regimen as first-line; reserve surgical intervention for truly refractory cases after prolonged medical therapy to minimize incontinence risk. 1

Common Pitfalls to Avoid

• Do not assume all anorectal pain is hemorrhoids – fissures produce stinging pain during defecation, while thrombosed external hemorrhoids cause constant pain with a palpable lump. 1
• Do not rush to surgery for acute fissures – 50% heal with conservative management alone within 10–14 days. 1, 2
• Do not ignore atypical fissure locations – lateral or multiple fissures require urgent evaluation for IBD, cancer, or infection before any treatment. 1, 2
• Do not use manual dilation – the 10–30% permanent incontinence risk is unacceptable. 1, 2, 3