Summary

• Causes severe pain on defecation, often described as 'like passing broken glass'. The pain may continue for 1 to 2 hours and can also be burning in nature.
• A small amount of fresh red blood is often passed on the stool.
• On examination of the anus, there is often marked spasm of the sphincter muscles, with significant tenderness often precluding digital examination.
• Initial treatment should include either topical glyceryl trinitrate or diltiazem, along with a programme of supportive care.
• Resistant or chronic fissures may benefit from botulinum toxin A, and most cases can be cured by surgical sphincterotomy or anal advancement flap.