Can Anal Fissures Disappear?
Yes, approximately 50% of acute anal fissures heal spontaneously within 10-14 days with proper conservative management, but chronic fissures rarely resolve without specific medical or surgical intervention. 1, 2
Natural History of Acute Anal Fissures
Acute fissures have excellent spontaneous healing rates when managed appropriately:
- 50% of acute anal fissures heal within 10-14 days with conservative care including fiber supplementation (25-30g daily), adequate fluid intake, warm sitz baths, and topical analgesics 1, 2
- Acute fissures may heal spontaneously even without intervention, though simple conservative measures significantly improve outcomes 3, 4
- Pain relief typically occurs within 14 days of appropriate treatment 2
Why Acute Fissures Can Heal
The pathophysiology involves internal anal sphincter hypertonia with decreased anodermal blood flow creating an ischemic environment 1, 5. Conservative measures address this by:
- Fiber supplementation softens stools and minimizes anal trauma 1
- Warm sitz baths promote sphincter relaxation, improving local blood flow 1
- Adequate hydration prevents constipation, reducing mechanical trauma 1
Chronic Fissures: A Different Story
Chronic fissures do not respond to conservative treatment alone and require specific intervention 4:
- Chronic fissures display signs of chronicity including sentinel skin tag, hypertrophied anal papilla, fibrosis, or visible internal sphincter muscle at the fissure base 5
- The risk of recurrent fissure remains high if causative factors (sphincter hypertonia, ischemia) persist 6
- Without addressing the underlying sphincter hypertonia, chronic fissures will not heal 1, 6
When Fissures Won't Disappear Without Treatment
If no improvement occurs after 2 weeks of conservative management, the fissure is unlikely to heal without specific medical therapy 2:
- Topical calcium channel blockers (0.3% nifedipine with 1.5% lidocaine) achieve 95% healing after 6 weeks by reducing internal anal sphincter tone and increasing local blood flow 1
- Topical nitroglycerin shows 25-50% healing rates but causes headaches in many patients 1
- Botulinum toxin injection demonstrates 75-95% cure rates with low morbidity 1
Surgical Intervention for Non-Healing Fissures
Lateral internal sphincterotomy remains the gold standard for chronic fissures unresponsive to 6-8 weeks of medical therapy, with high cure rates and low relapse, though it carries a small risk of minor permanent incontinence 1, 6:
- Surgery should only be considered for chronic fissures non-responsive after 8 weeks of non-operative management 2
- Lateral internal sphincterotomy is the most effective long-term treatment 6, 3
Critical Pitfalls
Manual anal dilatation is absolutely contraindicated due to unacceptably high permanent incontinence rates of 10-30% 1, 2
Red Flags Requiring Further Evaluation
Atypical fissure locations (lateral rather than midline) should prompt investigation for underlying conditions such as Crohn's disease, HIV, syphilis, tuberculosis, or anorectal cancer 2, 5: