Anal fissures (fissures in the anus) are a common anorectal disorder, usually accompanied by severe pain. An anal fissure is a wound or fissure in the anal canal or at the edge of the anus extending from the skin-mucosal junction to the dentate line. Anal fissures can be acute or chronic in onset. The disease can occur at all ages (anal fissures are the most common cause of rectal bleeding in infants), but are usually seen in young adults. Etiology Anal fissures can be caused by constipation and straining to defecate. Anal manometry studies of patients with anal fissures have found elevated anal resting pressure in patients, which may be the cause of the disease. Anal fissures are common in the posterior aspect of the anal canal. When an anal fissure occurs in an atypical location, especially on the flank, the physician should consider the possibility that the patient has a nonspecific inflammatory bowel disease, such as Crohn’s disease. Why some anal fissures heal on their own and others become chronic remains an open question. Persistent inflammation secondary to local ischemia, infection, or lymphatic obstruction may be responsible for the transformation into chronic fissures. Symptoms The typical complaints of patients with acute anal fissures are pain and bleeding. Pain usually occurs during and immediately after a bowel movement. Constipation often occurs first, and then once the pain begins, the problem is further exacerbated by the fear of pain during defecation and the refusal to defecate. This anxiety can lead to fecal blockage, especially in children and the elderly. Chronic anal fissures can present with anterior hemorrhoids, bleeding or pus, and itchy skin. Bleeding may or may not be present. A hypertrophied anal papilla can usually be palpated at the top of the ulcer. Anal fissures, anterior sentinel hemorrhoids, and enlarged anal papillae are known as the anal fissure triad. Medication In 2010, the American Association of Colorectal Surgeons Committee on Standardization published guidelines for the treatment of anal fissures. The guidelines state that the final judgment must be made by the physician in order to make an appropriate and specific treatment plan based on the individual patient’s condition. Recent flare-ups in patients with a history of anal fissures can usually be successfully treated with conservative treatments such as stool softeners, relaxants, a high fiber diet, increased water intake and sitz baths. To prevent recurrence, patients should be encouraged to continue to maintain a moderate diet. Topical anesthetic preparations (e.g., 5% lidocaine ointment) are usually used before or after a bowel movement to relieve pain. Non-surgical treatment is safe and has few side effects and is the treatment of choice. Others such as nitroglycerin ointment, calcium channel blocker ointment, botulinum toxin, etc. are also treatment options, but are less commonly used in clinical practice. Surgical treatment The choice of surgical procedure for anal fissure treatment depends on the duration of symptoms and the signs found. For acute anal fissures without skin prolapse, anal papillomegaly and anterior sentinel hemorrhoids, sphincter dilation and internal anal sphincterotomy are the two traditional surgical approaches. For chronic anal fissures with external symptoms or in cases of concomitant symptomatic hemorrhoids, local excisional therapy and sphincterotomy are better options.