EPIDEMIOLOGY & DEMOGRAPHICS
• Can occur at any age
• Most common in young and middle-aged adults
• Occurs in men > women
• Women more likely to have anterior fissure than men (10% vs. 1%, respectively)
• Most common cause of rectal bleeding in infants
• Common in women before and after childbirth
PHYSICAL FINDINGS & CLINICAL PRESENTATION
• Acute anal fissure:
1. Sharp burning or tearing pain exacerbated by bowel movements
2. Bright-red blood on toilet paper, a streak of blood on the stool or in the water
• Chronic anal fissure:
1. Pruritus ani
2. Pain seldom present
3. Intermittent bleeding
4. Sentinel tag at the caudal aspect of the fissure, hypertrophied anal papilla at the proximal end
• Underlying disease possible if the fissure:
1. Is ectopically located
2. Extends proximal to the dentate line
3. Is broad-based or deep
4. Is especially purulent
ETIOLOGY
• Most initiated after passage of a large, hard stool
• May result from frequent defecation and diarrhea
• Bacterial infections: TB, syphilis, gonorrhea, chancroid, lymphogranuloma venereum
• Viral infections: herpes simplex virus, cytomegalovirus, human immunodeficiency virus
• Inflammatory bowel disease (IBD): Crohn’s disease, ulcerative colitis
• Trauma: surgery (hemorrhoidectomy), foreign bodies, anal intercourse
• Malignancy: carcinoma, lymphoma, Kaposi’s sarcoma
DIAGNOSIS
DIFFERENTIAL DIAGNOSIS
• Proctalgia fugax
• Thrombosed hemorrhoid
WORKUP
• Digital rectal examination after lubricating the entire anus with anesthetic jelly (i.e., 2% lidocaine) and waiting 5 to 10 min
• Anoscopy
• Proctosigmoidoscopy to exclude inflammatory or neoplastic disease
• Biopsy if doubt exists about the etiology of the condition
• All studies done under adequate anesthesia
IMAGING STUDIES
• Colonoscopy or barium enema: if diagnosis of IBD or malignancy is suspected
• Small bowel series: occasionally obtained for similar reasons
• Biopsy to reveal caseating granuloma if TB is suspected
• Wet prep with darkfield examination to demonstrate treponemes if syphilis is suspected
TREATMENT
NONPHARMACOLOGIC THERAPY
• Sitz baths
• High-fiber diet
• Increased oral fluid intake
ACUTE GENERAL Rx
• Bulk-producing agent (i.e., Metamucil)/stool softener
• Local anesthetic jelly (may exacerbate pruritus ani)
• Nitroglycerin ointment
• Suppositories not recommended
• Surgery
CHRONIC Rx
• Surgery: lateral internal anal sphincterotomy
• Topical glyceryl trinitate ointment
• Injection of botulinum toxin (an injection into each side of the internal anal sphincter) is effective in healing chronic anal fissures in over 90% of patients.
DISPOSITION
Outpatient surgery
REFERRAL
• If fissure does not resolve with conservative therapy in 4 to 6 wk
• If patient prefers surgery for acute fissure
• If patient has chronic fissure

Diagram of the anorectum showing the fissure or ulcer triad.

Anal fissure

BASIC INFORMATION
Anal fissures are linear or rocket-shaped ulcers that are usually less than 5 mm in length. Most fissures are believed to arise from trauma to the anal canal during defecation, perhaps caused by straining, constipation, or high internal sphincter tone. They occur most commonly in the posterior midline, but 10% occur anteriorly. Fissures that occur off the midline should raise suspicion for Crohn's disease, HIV/AIDS, tuberculosis, syphilis, or anal carcinoma. Patients complain of severe, tearing pain during defecation followed by throbbing discomfort that may lead to constipation due to fear of recurrent pain. There may be mild associated hematochezia, with blood on the stool or toilet paper. Anal fissures are confirmed by visual inspection of the anal verge while gently separating the buttocks. Acute fissures look like cracks in the epithelium. Chronic fissures result in fibrosis and the development of a skin tag at the outermost edge (sentinel pile). Digital and anoscopic examinations may cause severe pain and may not be possible. Medical management is directed at promoting effortless, painless bowel movements. Fiber supplements and sitz baths should be prescribed. Topical anesthetics (EMLA cream) may provide temporary relief. Healing occurs within 2 months in up to 45% of patients with conservative management. Chronic fissures may be treated with topical 0.2-0.4% nitroglycerin or diltiazem 2% ointment (1 cm of ointment) applied twice daily just inside the anus with the tip of a finger for 4-8 weeks or injection of botulinum toxin (20 units) into the anal sphincter. All of these treatments result in healing in 50-80% of patients with chronic anal fissure, but headaches occur in up to 40% of patients treated with nitroglycerin. Fissures recur in up to 40% of patients after treatment. Chronic or recurrent fissures benefit from lateral internal sphincterotomy; however, minor incontinence may complicate this procedure.
SYNONYMS
Anorectal fissure
Anal ulcer