Anal fissure, or fissure-in-ano, is defined as a tear in the squamous epithelium of the anus distal to the dentate line. It is characterized by severe pain during and after defecation often causing a great deal of distress in affected individuals. Minimal bleeding can occur and is usually limited to bright red blood on toilet paper or the surface of stool . Chronic anal fissures may present with perianal swelling, mucous drainage, or a sentinel pile . © Springer-Verlag London Limited 2010.