What is a chronic anal fissure?

Information for the public

An anal fissure is a common and often painful problem caused by a small tear or ulcer (open sore) in the lining of the anus (back passage). This can cause bleeding, local itching and pain with a bowel movement, which can be severe. When someone has an anal fissure the first treatments can include a high-fibre diet, laxatives and applying anaesthetic ointments to the affected area. Anal fissures usually heal within a few weeks but those that have not healed after 4–6 weeks are called chronic fissures.

If someone has a chronic fissure, it is thought that the reason it has not healed is that the ring muscle (sphincter) that goes around the anus (back passage) has become so tense that the flow of blood to the lining of the anus is reduced. That means that not enough oxygen (carried by the blood) gets to the fissure (or tear). Without enough oxygen, the cells which make up the lining can't grow and repair (heal) the fissure (or tear).

A licensed medicine for treating chronic anal fissure in adults (over 18 years of age) is available in the UK: glyceryl trinitrate ointment (also called Rectogesic 4 mg/g Rectal Ointment). Glyceryl trinitrate is commonly abbreviated to GTN. GTN ointment is applied to the affected area twice a day and is used to relieve pain caused by the fissure. The GTN helps the ring muscle (sphincter) to relax which allows more blood to flow to the lining of the anus (back passage) so that the cells which make up the lining can heal the fissure (or tear).

Treatment with GTN often causes headache and about 20 in every 100 people using it have very bad headaches. These can be treated with pain-killers such as paracetamol but the headache causes some people to stop using the medicine.

If the person has had to stop treatment with GTN, or the fissure hasn't healed or has come back, other treatments can be tried. These include botulinum toxin injections (such as Botox or other brands) into the area around the anus (back passage) or a surgical procedure called spincterotomy. Both these treatments help the ring muscle (sphincter) to relax and allow more blood to flow to the lining of the anus (back passage). Diltiazem hydrochloride cream or ointment can also be tried. It is also sometimes used in children; there is no licensed medicine for treating chronic anal fissures in children.