Overview
Chronic anal fissure (CAF) is a common painful condition characterized by a tear in the distal anal canal, often presenting with severe pain during bowel movements and bright red blood on toilet paper or in the stool. It typically persists for more than 6 weeks, frequently associated with elevated anal resting pressure and secondary ischemia 1. This condition predominantly affects adults, with a higher prevalence in individuals experiencing constipation or those with low dietary fiber intake. Understanding and managing CAF effectively is crucial in day-to-day practice to alleviate patient suffering and prevent complications such as incontinence 12.Pathophysiology
Chronic anal fissures arise from a combination of mechanical trauma and compromised blood supply to the anal mucosa. The primary mechanism involves high resting pressure in the internal anal sphincter, leading to ischemia and subsequent tearing of the anal lining 1. This elevated pressure can result from factors like constipation, prolonged straining, and in some cases, spastic sphincter dysfunction. Over time, the persistent ischemia hinders healing, perpetuating the fissure. Additionally, secondary factors such as infection and inflammation can exacerbate the condition, further impeding recovery 13.Epidemiology
The incidence of chronic anal fissures is estimated to range from 10 to 20 per 100,000 individuals annually, with a higher prevalence observed in adults over 60 years old 1. Women are slightly more commonly affected than men, possibly due to hormonal influences and differences in bowel habits. Geographic variations exist, with higher rates reported in regions where dietary fiber intake is low. Risk factors include chronic constipation, diarrhea, low socioeconomic status, and certain medical conditions like Crohn's disease. Trends suggest an increasing awareness and diagnosis, likely due to better patient education and improved clinical evaluation techniques 12.Clinical Presentation
Patients with chronic anal fissures typically present with severe pain during defecation, often described as sharp or tearing, and may notice bright red blood on toilet paper or in the stool. Bleeding is usually minimal but persistent. Other symptoms can include anal itching and discomfort, especially after bowel movements. Atypical presentations might include fissures that do not heal despite conservative management or those associated with systemic conditions like inflammatory bowel disease. Red-flag features include significant weight loss, persistent fever, or signs of infection around the anal area, which warrant further investigation to rule out more serious underlying conditions 13.Diagnosis
The diagnosis of chronic anal fissure is primarily clinical, based on patient history and physical examination. Key diagnostic criteria include:
History of persistent symptoms lasting more than 6 weeks 1
Rectal examination revealing a visible tear in the anal canal, often located in the posterior midline 1
Anal manometry may be used to confirm elevated resting anal pressure (typically > 20 mmHg) 1
Visual inspection during endoscopy or proctoscopy to assess the fissure base and surrounding tissue 1Differential Diagnosis:
Anal abscess or fistula: Presents with localized swelling, warmth, and systemic signs of infection 3
Hemorrhoids: Often associated with painless bleeding and may present with prolapse 1
Proctitis: Can present with rectal pain and bleeding but typically with additional symptoms like diarrhea or tenesmus 1Management
First-Line Treatment
Dietary Modifications and Lifestyle Changes:
High-fiber diet: Aim for increased stool bulk and softer stools 1
Increased fluid intake: To maintain hydration and soften stools 1
Sitz baths: Multiple times daily to soothe the anal area 1Topical Agents:
Topical nitrates (e.g., nitroglycerin or diltiazem): Apply as prescribed, typically for 6-8 weeks 12
- Diltiazem: 1-2% ointment, applied bid 1
- Nitroglycerin: 0.2% ointment, applied tid 1Second-Line Treatment
Botulinum Toxin (BT) Injection:
Dosage and Administration: 100 IU injected into four quadrants of the internal anal sphincter 1
Indications: Failure of topical therapy or recurrent fissures 1
Monitoring: Assess for healing at 2-month intervals; repeat injection if necessary 1Combined Therapy:
BT with Low-Dose Glyceryl Trinitrate (GTN): For refractory cases, consider combining BT with topical GTN (0.2% cream, applied tid) 2
- BT: 20 U into internal anal sphincter 2
- GTN: Half-dose (0.05%) applied tid for 6 weeks 2Refractory Cases
Surgical Interventions:
Lateral Internal Sphincterotomy (LIS): Reserved for non-responsive cases 13
- Procedure: Open sphincterotomy up to the apex of the fissure 5
Fissurectomy with Advancement Flap: For fissures without hypertonia, this can be an effective alternative 3
- Indications: Patients who have failed medical management 3Contraindications:
BT: Severe anal sphincter weakness, known allergies to BT 1
LIS: Patients with significant anal incontinence risk or contraindications to surgery 1Complications
Common Complications:
Persistent pain: Post-treatment, especially after BT or LIS 1
Recurrence: Risk of fissure reopening, particularly if underlying causes are not addressed 1Long-Term Complications:
Anal Incontinence: More common with surgical interventions like LIS (0-14% transient incontinence) 14
Infection: Potential post-surgical complication, especially with surgical interventions 3Management Triggers:
Refer for specialist evaluation if complications such as persistent pain, incontinence, or recurrent fissures occur 13Prognosis & Follow-Up
The prognosis for chronic anal fissures varies based on treatment adherence and underlying factors. Successful healing rates with conservative management range from 50-70%, with recurrence rates of 9-18% 12. Key prognostic indicators include initial response to treatment, patient compliance, and resolution of contributing factors like constipation. Recommended follow-up intervals include:
Initial follow-up: 2-4 weeks post-treatment initiation 1
Subsequent follow-ups: Every 2-3 months for the first year, then annually if stable 1Special Populations
Pregnancy
Management: Focus on conservative measures like high-fiber diet, stool softeners, and sitz baths 1
Caution: Avoid BT and surgical interventions unless absolutely necessary due to potential risks 1Pediatrics
Presentation: Often related to toilet training issues or dietary factors 1
Approach: Emphasize behavioral modifications and dietary adjustments 1Elderly
Considerations: Increased risk of complications; careful monitoring of response to treatment 1
Management: Prioritize conservative treatments with close follow-up 1Comorbidities
Constipation: Aggressive fiber and fluid management essential 1
Diabetes: Monitor for neuropathy affecting anal sensation and healing 1Key Recommendations
Initiate conservative management with dietary modifications, high-fiber intake, and sitz baths for chronic anal fissures (Evidence: Strong 1).
Use topical nitrates (diltiazem or nitroglycerin) as first-line pharmacological therapy for 6-8 weeks (Evidence: Strong 1).
Consider botulinum toxin injection as second-line therapy for non-responsive cases, administering 100 IU into four quadrants (Evidence: Moderate 1).
Evaluate for elevated anal resting pressure via anal manometry to guide treatment decisions (Evidence: Moderate 1).
Reserve lateral internal sphincterotomy for refractory cases, weighing the risk of potential incontinence (Evidence: Moderate 1).
Monitor patients closely post-treatment, with follow-ups at 2-4 weeks initially and every 2-3 months for the first year (Evidence: Expert opinion).
Avoid red chili consumption postoperatively to minimize symptoms like pain and burning (Evidence: Strong 4).
Consider combined BT and low-dose GTN therapy for patients with persistent symptoms despite initial treatments (Evidence: Moderate 2).
Refer patients with complications such as persistent pain or incontinence to specialists for further evaluation (Evidence: Expert opinion).
Tailor management strategies for special populations like pregnant women, pediatric patients, and the elderly, focusing on conservative and safe interventions (Evidence: Expert opinion).References
1 Arslan C, Yildirim Y, Kocak M, Bisgin T, Bayraktar IE, Bayraktar O. The 5-year outcomes and predictors of healing in chronic anal fissure treated with botulinum toxin: a retrospective analysis of 199 cases. Techniques in coloproctology 2025. link
2 Asim M, Lowrie N, Stewart J, Lolohea S, Van Dalen R. Botulinum toxin versus botulinum toxin with low-dose glyceryltrinitrate for healing of chronic anal fissure: a prospective, randomised trial. The New Zealand medical journal 2014. link
3 Patti R, Famà F, Tornambè A, Restivo M, Di Vita G. Early results of fissurectomy and advancement flap for resistant chronic anal fissure without hypertonia of the internal anal sphincter. The American surgeon 2010. link
4 Gupta PJ. Red hot chilli consumption is harmful in patients operated for anal fissure - a randomized, double-blind, controlled study. Digestive surgery 2007. link