Anal fissures are splits or cracks in the lining of the anal opening. The most common cause of an anal fissure is the passage of very hard or watery stools. The break in the anal lining exposes the underlying muscles that control the passage of stool through the anus and out of the body. An anal fissure is one of the most painful problems because the exposed muscles become irritated from exposure to stool or air and lead to intense burning pain, bleeding, or spasm after bowel movements.
Initial treatment for anal fissures includes pain medicine and dietary fiber to reduce large, bulky stools and sitz baths (sitting in a few inches of warm water). If these treatments don’t relieve pain, surgery might be needed to repair the sphincter muscle.