What is an anal fissure?

An anal fissure is a small tear or open sore in the anus. It can cause pain and bleeding when you pass a bowel movement, especially if you are constipated. 

Anus

The opening at the end of the anal canal, between the buttocks, through which faecal matter and intestinal gas exits the body.

Causes

Anal fissures are caused by an injury that stretches or tears the anus. To help protect the anus from further damage, the muscle around the anus, known as the anal sphincter, tightens. This leads to further pain and impaired healing. 

The causes for an anal fissure include: 

  • Constipation - passing large, dry stools can stretch and damage the lining of your anus;
  • Diarrhoea - explosive or burning diarrhoea can damage the lining of the anus;
  • Pregnancy - multiple pregnancies and childbirth can cause anal fissures due to the straining and pushing of childbirth;
  • Anal sex - anal sex or insertion of foreign objects in the anus can tear the lining and cause damage;
  • Inflammatory bowel disease - if you have an inflammatory bowel disease, such as Crohn's disease, you are at higher risk of developing anal fissures;
  • Sexually-transmitted infections - in some cases of herpes and syphilis, anal damage can occur, due to the infection. 

Other causes

In some circumstances the fissure is caused by very tight anal sphincter muscles. You have two sphincters in your anus: the outer one, which you control, and the inner one, which you do not consciously control. The inner sphincter is under constant pressure, keeping waste inside. In some people the tension in this muscle is very high, reducing blood flow to the area and causing more spasms. This tension is considered to delay healing and can be addressed with medications or, in some cases, surgery.

Anal sphincter

A ring of muscle that controls the opening and closing of the anus.

Anus

The opening at the end of the anal canal, between the buttocks, through which faecal matter and intestinal gas exits the body.

Inflammatory bowel disease

A group of conditions characterised by chronic, episodic inflammation of the bowels, including Crohn's disease and ulcerative colitis.

Anal sex

Sexual intercourse that involves penetration of the anus with the penis.

Risk factors

The main risk factors for anal fissures include:

Inflammatory bowel disease

A group of conditions characterised by chronic, episodic inflammation of the bowels, including Crohn's disease and ulcerative colitis.

Anal sex

Sexual intercourse that involves penetration of the anus with the penis.

Signs and symptoms

An anal fissure usually appears in the back region of your anus. It can look like a small hole or split in the skin, it may be ulcerated. In a condition, called Crohn's disease, there may be multiple fissures with a slightly bluish skin discolouration. With any rectal bleeding and ulceration your doctor will want to rule out other causes including anal or rectal cancer, which can have similar symptoms to an anal fissure.

Anal fissure in the lining of the anus. 

Bleeding

You may find small amounts of bright red blood in the toilet pan or on toilet tissues after you have passed a bowel movement. Your stools may be coated in blood.

Pain

You may feel a sharp tearing or burning pain, during or just after you have passed a large or dry stool. The pain can last for minutes or hours and sometimes radiate down the back of your legs. You may also find that sitting on hard surfaces causes discomfort or pain.

Anus

The opening at the end of the anal canal, between the buttocks, through which faecal matter and intestinal gas exits the body.

Ulceration

The formation of an ulcer, which is an open sore in the skin or mucous membranes, such as those of the stomach lining, intestine or mouth.

Rectal cancer

A cancer in the very lower end of the large intestine that is characterised by a change in bowel habits or passage of blood.

Methods for diagnosis

Your doctor will usually be able to diagnose them by visual examination only. Very gently parting your buttocks to view the anus will usually suffice. If further tests are required these can be done using local anaesthetic to avoid pain. These may include:

Digital rectal examination

During a digital rectal examination (DRE) your doctor may use a topical anaesthetic cream to numb your anal region before putting a lubricated, gloved finger in your anus to feel for abnormalities or lumps, and;

Anoscopy, proctoscopy and sigmoidoscopy

Your doctor may wish to perform one of these tests to further investigate the fissure or cause of rectal bleeding.  They will use a topical anaesthetic cream to numb your anal region before beginning the examination. A tubular instrument is inserted into the anus and can be used to look at the walls of the anus (anoscope), rectum (proctoscope) and sigmoid colon (sigmoidoscope). The type of instrument will depend on how far into the bowel your doctor needs to see. These tests can usually be performed in the doctor's rooms and do not require any sedation or general anaesthetic.  As these instruments are quite short, areas of the large bowel beyond the sigmoid colon cannot be examined.

Colonoscopy

Your doctor may also refer you for a colonoscopy if they are concerned about potential causes further up the large bowel. This procedure is usually done in an operating theatre and you will be sedated. During a colonoscopy, the entire length of the large bowel can be examined using a long tube with a camera called a colonoscope. This test is the preferred method for excluding bowel cancer and may be used to further investigate cases of rectal bleeding or inflammatory bowel disease, such as Crohn's disease.

Anus

The opening at the end of the anal canal, between the buttocks, through which faecal matter and intestinal gas exits the body.

General anaesthetic

An anaesthetic given to a person to put them to sleep while having an operation or medical procedure. Afterwards, the person regains consciousness and usually has no memory of the procedure. A general anaesthetic is given in hospital by a specialist called an anaesthetist.

Inflammatory bowel disease

A group of conditions characterised by chronic, episodic inflammation of the bowels, including Crohn's disease and ulcerative colitis.

Local anaesthetic

A type of medication that, when administered to an area, creates a localised loss of sensation by blocking nerve activity.

Rectum

The final part of the large intestine, leading to the anus.

Sigmoid

The part of the large intestine before the rectum.

Types of treatment

While most cases of anal fissure will heal themselves within 2-4 weeks without any treatment, the following may also be recommended:

Self care

Preventing constipation is the first form of treatment, as soft stools prevent further pain and damage, giving your rectum a chance to heal. Passing large, dry stools can stretch and reopen semi-healed fissures, causing extreme pain and preventing the fissure healing. Also, decreasing the tension in your anal sphincter will increase blood flow and aid faster healing.

High-fibre diet

Try to avoid constipation by following a high-fibre diet containing plenty of fruit, vegetables and wholegrain products and increasing your water intake. Taking a fibre supplement (available at your local pharmacist or supermarket) may also help.

Laxatives

Your doctor may suggest you take laxatives for a few weeks to keep your stools soft, as this will minimise pain and further damage. Your doctor may also recommend suppository laxatives, which are soft capsules that are inserted into your rectum and break down dry stools.

Moist toilet tissue

Using moist, unperfumed toilet paper or wipes will help keep the anal area clean and cause less irritation than dry paper. If you are in extreme pain, use warm water with cotton buds or cotton wool. It is very important to keep the fissure clean to avoid infection.

Sitz bath

Sitting for 15 minutes after each bowel movement in a warm shallow bath or using a Sitz bath with added salt, can greatly reduce the pain associated with anal fissures. The warm water increases circulation and will relax your anal sphincter to reduce spasms and pain.

Exercise

Try to avoid sitting for long periods of time and exercise as often as you can, as this will increase blood circulation to your anal region and aid healing.

Medications

Creams

Several types of creams can help, including:

  • Anaesthetic cream to reduce pain, itching and inflammation. These do not heal the fissure, but will help with the pain by numbing the area, prior to passing a stool; 
  • Hydrocortisone creams - these may be prescribed to help with localised irritation in the short-term, but can impair healing if used long-term;
  • Zinc oxide cream or petroleum jelly - applying these to your anus will help soothe irritation and aid healing, and;
  • Glyceryl trinitrate (GTN) - this is an ointment that increases blood supply to your anus by expanding the blood vessels in the area. The aim of this treatment is to lessen pain and increase healing capacity. You will usually apply it directly to the anal region twice per day for up to eight weeks. A common side effect of using GTN is headache and dizziness; your doctor will advise if it is suitable for you.

Pain-relief medicaitons

You may be advised to take over-the-counter pain-relief medications, such as paracetamol or ibuprofen, to help with pain. Avoid codeine, as it may cause constipation.

Surgical procedures

Surgery is seen as one of the most effective treatments for chronic anal fissures but like most procedures it also carries a small risk of complications.

Botulinum toxin injections

A relatively new treatment option, when other treatments have not helped, is to inject botulinum toxin into your anal sphincter. The aim is to reduce the tension from the sphincter, which can reduce pain and allow time for the fissure to heal. The effects are supposed to last around three months. Side effects, such as potential incontinence, need to be considered and discussed with your doctor.

Lateral internal sphincterotomy

This procedure involves making a small cut through your anal sphincter muscle, to reduce the amount of tension present. This helps your fissure to heal and lessens the chances of developing another fissure. It will be done under general or local anaesthetic but usually would not involve you having to spend the night in hospital. Recovery is normally within four weeks of surgery, with good success rates. There is a very small risk of being unable to control passing gas or stools, but this function usually returns eventually.

Advancement anal flaps

This procedure is only considered in chronic conditions. It involves taking healthy tissue from elsewhere in your body and using it to repair your fissure, increasing blood supply and therefore healing. This would be done under general anaesthetic and you may have to stay overnight in hospital.

Dilation surgery

You may undergo surgery to gently dilate (stretch) your anal sphincter. This will be done under a local or general anaesthetic and usually does not require an overnight stay in hospital. Accidental leakage of stools can be a complication of this procedure.

Anal sphincter

A ring of muscle that controls the opening and closing of the anus.

Anus

The opening at the end of the anal canal, between the buttocks, through which faecal matter and intestinal gas exits the body.

General anaesthetic

An anaesthetic given to a person to put them to sleep while having an operation or medical procedure. Afterwards, the person regains consciousness and usually has no memory of the procedure. A general anaesthetic is given in hospital by a specialist called an anaesthetist.

Incontinence

The uncontrollable loss, small or large, of bladder or bowel control, resulting in leakage of their contents.

Laxatives

Any substance that causes or encourages bowel movements.

Local anaesthetic

A type of medication that, when administered to an area, creates a localised loss of sensation by blocking nerve activity.

Rectum

The final part of the large intestine, leading to the anus.

Sitz bath

Sitz baths are special containers which can be fitted on your toilet seat. They are designed to bathe your buttocks and genitals in water, without having to get fully undressed.

Botulinum

A nerve toxin produced by the bacterium Clostridium botulinum, which causes muscle paralysis. It can be used cosmetically (known as Botox or by its other trade names) in low doses to relax facial wrinkles and for various medical purposes.

Potential complications

While most anal fissures will heal naturally, without further medical attention, the following are some potential complications you may experience:

  • Anal fistulas - these are abnormal channels that form between your anus and other parts of your bowel;
  • Chronic anal fissure - this can occur over time, resulting in scarring at the site of the original fissure. You may require surgery to rectify this condition, and;
  • Anal stenosis - this occurs when your anal passage becomes smaller than usual, due to scar tissue or excessive contraction (spasm) of your anal sphincter.

Anal sphincter

A ring of muscle that controls the opening and closing of the anus.

Anus

The opening at the end of the anal canal, between the buttocks, through which faecal matter and intestinal gas exits the body.

Prognosis

The outlook for recovery from an anal fissure is good, as fissures are easily treated with lifestyle changes, creams, medications or surgery. They do tend to reoccur though.

Prevention

Some simple things you can do to prevent getting an anal fissure include:

  • Following a healthy diet containing high-fibre foods, such as fruits, vegetables, cereals and wholegrain products;
  • Drinking more water throughout the day to help keep your stools soft and keep your digestive system moving, and;
  • Getting active. Try to avoid sitting for long periods of time and exercise as often as you can.