Fissures and pruritus ani

Abstract

Anal fissure is a linear split in the lining of the distal anal canal that causes pain and bleeding on defecation. It usually occurs in the posterior midline position where the blood supply is poorest. Most acute fissures heal spontaneously or with simple dietary measures. Chronic fissures fail to heal after six weeks and become a shallow ulcer; most of these require further intervention. They are frequently associated with increased resting anal pressures. Treatments are directed at reducing these pressures by pharmacological and surgical means. Nitrates such as glyceryl trinitrate and the calcium channel blockers diltiazem and nifedipine cause a reversible ‘chemical sphincterotomy.’ Topical application of these agents is usually the first-line treatment. Injection of botulinum toxin temporarily prevents the release of acetylcholine from nerve endings and reduces resting anal pressures. It often heals fissures that fail to respond to topical therapies. Lateral internal sphincterotomy is an effective treatment, but should be reserved for fissures that have failed medical treatment. It causes permanent damage to the sphincter and may lead to varying degrees of incontinence. Pruritus ani is the symptom of perianal irritation that causes itching. It may be secondary to an underlying cause, but most cases are idiopathic. Treatment is directed at underlying disease, attention to perianal hygiene and keeping the affected area dry. Injection of methylene blue has been used in those cases resistant to conventional treatments.