An anal fissure is a split in the skin of the anus. It is commonly thought to occur when a patient passes a very hard stool and splits the skin. They are also common during or after pregnancy and rarely in association with other diseases such as Crohn’s disease. The main symptom of a fissure is pain, which typically occurs after a bowel motion and can last from a few minutes to several hours afterwards. Other symptoms include bleeding and itching.
Anal fissures can be difficult to heal. Patients will often become constipated through the fear of pain associated with a bowel motion. The sphincter muscle in the bottom may become very tight and makes the fissure less likely to heal as the blood supply to the area is reduced.
Most fissures can be healed with pastes applied to the bottom, such as glyceryl trinitrate (rectogesic) or diltiazem (anoheal). These are often combined with laxatives to keep the stools soft. Whilst effective in about two thirds of patients, some will find that they get bad headaches with these drugs from absorption of a small amount through the skin. For patients who do not have their fissures healed successfully with these pastes, we would normally recommend an injection of botulinum toxin, often done on as an out-patient under a local anaesthetic. Surgery is only rarely necessary.