Anal fissures are longitudinal or elliptical tears of the squamous lining of the distal anal canal. If present for less than 6 weeks they are defined as acute, and chronic if present for more than 6 weeks.

Risk factors

• constipation
• inflammatory bowel disease
• sexually transmitted infections e.g. HIV, syphilis, herpes
• pregnancy: increased risk in third trimester and post-delivery

PC

• painful, bright red, rectal bleeding - typically noted on stool or toilet paper
• Severe anal pain or a tearing sensation during bowel movements, lasting for hours afterward.
• Anal spasms reported by about 70% of patients.
• around 90% of anal fissures occur on the posterior midline.
  • if the fissures are found in alternative locations then other underlying causes should be considered e.g. Crohn's disease

Management

Management of an acute anal fissure (< 1 week)

• soften stool
  • dietary advice: high-fibre diet with high fluid intake
  • bulk-forming laxatives are first-line - if not tolerated then lactulose should be tried
• lubricants such as petroleum jelly may be tried before defecation
• topical anaesthetics
• analgesia - lidocaine cream or jelly