How common are anal fissures?
Anal tears (fissures) are common and probably affect about 1 in 350 people each year. They are more common in people aged between 15 and 40 years but can occur at any age, including in very young children. Women who are pregnant or have recently had a baby are at higher risk of anal fissures, while they are much less common in the elderly.
Anal fissure causes
Anal fissures are most often caused by damage to the back passage (anus). Stretching and tearing can occur when a person passes particularly hard stools.
In most people, this skin damage will heal quickly without any problems. However, some people seem to have a higher than normal tone (pressure) of the muscle around the anus (the anal sphincter). The muscle is 'tighter' than usual.
It is thought that this increased tone may reduce the blood supply to the anus and so slow down the skin healing process. This can cause an anal tear (fissure) to develop. Once a fissure has developed, pain when passing stools can increase the anal tone further. This makes the pain worse, which can then increase the muscle tone even more and further slow down the healing process.
Constipation can make an anal fissure more likely to develop. There's major variation in 'normal' frequency of bowel-opening between different people. For some, 2-3 times a day is standard and going three days without a bowel movement would be very unusual. For others, going more often than every 2-3 days would be equally odd. Constipation either happens if your stools become hard and it's harder and/or more painful to go, or you're going significantly less often than usual.
Lots of factors can cause constipation, but among the most common are not eating enough fibre (roughage) and not drinking enough fluids. If you're generally unwell, particularly with a feverish illness, you'll be losing more fluid than usual - due to sweating from your high temperature (fever) - and often eating less. Some medications - particularly strong painkillers - can also make you constipated. So can medical conditions such as an underactive thyroid gland.
Sometimes an anal fissure occurs if you have bad diarrhoea. Anal fissures are also more common during pregnancy and childbirth. An anal fissure occurs in about 1 in 10 women during childbirth.
In a small number of cases, a fissure occurs as part of another condition. For example, as a complication of Crohn's disease, ulcerative colitis or a sexually transmitted infection such as anal herpes infection. In these situations you will also have other symptoms and problems that are caused by the underlying condition. These types of fissures are not dealt with further in this leaflet.
Anal fissure treatment
For most people the tear (fissure) heals within a week or so, just like any other small cut or tear to the skin.
Treatment aims to ease the pain and to keep the stools (faeces) soft whilst the fissure heals.
Easing pain and discomfort
- Warm baths are soothing and they may help the back passage (anus) to relax which may ease the pain.
- A cream or ointment that contains an anaesthetic such as lidocaine may help to ease the pain. You should only use this for short periods (up to 5-7 days). If you use it for longer, the anaesthetic may irritate or sensitise the skin around the anus. You can obtain one of these creams or ointments on prescription. You can also buy some of these products at pharmacies, without a prescription.The cream/ointment should be applied before going to the toilet.
- A cream or ointment that contains steroid medication may be prescribed by a doctor if there is a lot of swelling (inflammation) around the fissure. Steroids reduce inflammation and they may help to reduce any swelling around a fissure. This may help to ease any itch and pain. You should not use it for longer than one week at a time.
- Wash the anus carefully with water after you go to the toilet. Dry gently. Don't use soap whilst it is sore as it may cause irritation.
- Painkillers such as paracetamol or ibuprofen may help to ease the pain (but avoid codeine - see below).
Avoid constipation and keep the stools soft
- Eat plenty of fibre which is found in fruit, vegetables, cereals, wholemeal bread, etc.
- Have lots to drink. Adults should aim to drink at least two litres (10-12 cups) of fluid per day. You will pass much of the fluid as urine. However, some is passed out in the gut and softens the stools. Most sorts of drink will do; however, alcoholic drinks can lead to lack of fluid in the body (dehydration) and may not be so good.
- Fibre supplements and laxatives. If a high-fibre diet is not helping, you can take fibre supplements (bulking agents) such as ispaghula, methylcellulose, bran or sterculia. Methylcellulose also helps to soften stools directly, which makes them easier to pass. You can buy these at pharmacies or obtain them on prescription. A laxative such as lactulose or a macrogol laxative may sometimes be suggested.
- Toileting. Don't ignore the feeling of needing to pass stools. Some people suppress this feeling and put off going to the toilet until later. This may result in bigger and harder stools forming that are more difficult to pass later.
- Avoid painkillers that contain codeine, such as co-codamol, as they are a common cause of constipation. Paracetamol is preferable to ease the discomfort of a fissure.