What is Anal Fissure - A small incision or tear in the lining of the anal opening is known as an anal fissure, and it can cause considerable pain and bleeding during bowel movements. It is not a life-threatening condition, but it can cause pain and discomfort that can become unbearable if not treated promptly. An anal fissure can affect individuals of any age group. This condition might occur in children or new-borns who are suffering from constipation.