Anal Fissure

What is an anal fissure?
A fissure is a split in the skin at the opening of the anus, leaving exposed some of the muscle fibres of the anal canal. Pain results from constant opening of the wound when the bowels are open and this is often accompanied by bleeding. In addition, the inner circle of muscle in the anal canal (called the internal sphincter) goes into spasm: this makes the pain worse and can prevent healing. Anal fissures are different from haemorrhoids (piles) and are not cancerous.

What are the symptoms?

• Pain on emptying the bowel that may persist for minutes or hours afterwards; the pain is typically sharp rather than an ache
• Bright red bleeding on defaecation
• A skin tag, a piece of skin which hangs from surrounding skin, at the site of the fissure can develop if the fissure is long-standing

What treatments are available?
The aim of treatment is to relax the spasm in the internal sphincter (muscle at the upper end of the anal canal). This improves the blood supply to the fissure and prompts healing in the majority of the patients.

What can I do to help?
Eating a high fibre diet and drinking plenty of water (six to ten glasses a day) is important to keep your bowel motions soft. Sometimes a fibre supplement such as Fybogel may help.

A fifteen-minute bath in water as warm as you can tolerate several times daily (or as often as you require) can be very soothing and provide several hours of pain relief.

Are there medications that can help?
Glyceryl trinitrate (GTN) and Diltiazem ointment are medications that can be locally applied to relax the sphincter inside the back passage. Both are applied to the outside of the anus by a gloved hand twice a day. GTN can produce a side effect of headache whereas Diltiazem sometimes makes the skin around the anus sensitive and sore. If either of these side effects occur it is possible to swap over to the other ointment.

What surgical treatments are available?
The injection of botulinum toxin (botox) is a technique that helps relax the internal sphincter and is injected under a general anaesthetic. The main advantage of botox is that it is a one off treatment that lasts for three months, during which time the fissure should heal. Rarely botox can result in undesirable side effects such as difficulty with the control of wind and possibly liquid stool from the back passage.

Surgery for anal fissure is called an internal sphincterotomy. This means that part of the internal sphincter muscle is cut. The cut relieves the spasm of the muscle, stops the pain and allows the fissure to heal. It is not usually necessary to remove or suture (stitch) the fissure itself. The operation is very effective but carries a small risk (10-20%) of a change in the ability to control your bowels or passing wind. An experienced health professional will explain these options and decide with you on which is best for your individual situation.