Anal fissure

An anal fissure occurs when the area around the anus is stretched and the skin tissue tears. This damage is often the result of passing hard or large stools and can cause pain and bleeding.

Anal fissures are a common complaint that can happen at any age, affecting one in 10 people. They’re more likely between the ages of 15 and 40 and affect both men and women. Pregnancy and childbirth can increase the risk of anal fissures.

In most cases, anal fissures aren’t serious and heal quickly, without the need for treatment. If you have any concerns, or an anal fissure hasn’t healed after six weeks (a chronic anal fissure), see your GP.

The main anal fissure symptoms are:

• Pain around your anus (anal pain) 
• Sharp pain while passing a stool followed by burning pain lasting up to several hours 
• Bleeding after you’ve passed a stool (anal bleeding) — you may notice bright red blood on your stool or on the toilet paper 
• Itchy, irritated anus 
• A visible tear in the skin on your anus
• A tag of skin on your anus (a sentinel pile)

You may feel embarrassed about seeking treatment for an anal fissure. However, it is important to see a GP so they can rule out certain conditions with similar symptoms. 

While most anal fissures do not need treatment to get better, your GP can advise you on what to do to relieve your symptoms and avoid future anal fissures. 

Your GP will confirm if you have an anal fissure or a condition with similar symptoms, such as piles (haemorrhoids) or bowel polyps.

They’ll ask about your anal fissure symptoms, including anal fissure pain, your bowel habits and your general health. 

Your GP will also examine your anus. However, a rectal examination, where your GP inserts a lubricated, gloved finger into your anus, is not usually carried out to diagnose an anal fissure. 

If your anal fissure is not healing properly, your GP might measure the pressure applied by your anal sphincter — this is a group of muscles that controls the opening and closing of your anus. Increased pressure can reduce the blood supply to the anus, which slows down healing.

Your GP may refer you to a consultant for further investigations. These investigations might include an examination of the inside of your rectum (proctoscopy) and/or an ultrasound scan.

Anal fissures are usually caused by damage to the lining of the anus or the end part of the large intestine (anal canal). There are multiple causes.

Diarrhoea or constipation can both cause anal fissures. The frequency of bowel movements varies considerably between individuals. However, not passing a stool for more than three days is generally considered unusual and is a sign of constipation. Constipation occurs when stools become hard and painful or difficult to pass. Constipation can be caused by:

• Certain medications
• Certain medical conditions, such as an underactive thyroid
• Not eating enough fibre or drinking enough fluids

Certain infections can also cause anal fissures, including: 

• HIV
• STDs (sexually transmitted diseases), such as syphilis or herpes, if they infect the anal canal
• Tuberculosis

Other causes of anal fissures include: 

• Pregnancy and childbirth – about one in 10 women develop an anal fissure after having a baby
• Inflammatory bowel diseases, such as Crohn’s disease and ulcerative colitis
• Taking certain medications, including some pain relief drugs and some chemotherapy drugs
• Anal sex
• Certain cancers, such as anal cancer
• An unusually tight anal sphincter 

Sometimes the exact cause of an anal fissure can’t be found. 

Sometimes an anal fissure might fail to heal or the tear might extend to the surrounding muscles. Further treatment will, therefore, be needed. Also, once you have had one anal fissure, you are at greater risk of having another. 

Anal fissures often heal on their own in a few weeks. Occasionally, they may take six weeks or more to heal completely. Treatments are therefore focused on pain relief and keeping stools soft while the anal fissure heals. 

To relieve anal fissure pain, try taking over-the-counter pain relief, such as ibuprofen and paracetamol. Avoid taking painkillers containing codeine as codeine is known to cause constipation. Also, try eating foods rich in fibre that will soften your stools. You might also find it helps to sit in a warm bath after passing stools.

Constipation and passing hard or large stools can prevent an anal fissure from healing and can also trigger a recurrence. To reduce the risk of constipation and straining excessively when passing a stool, you should:

• Ensure your diet contains lots of fibre, such as fruit, vegetables, wholemeal bread and cereals
• Drink plenty of fluids, including water
• Take regular exercise

Make sure you don’t resist the urge to pass a stool. This can make the stool more painful or difficult to pass later as it becomes drier and harder. 

You can also try taking fibre supplements and laxatives, such as ispaghula husk, methylcellulose, bran or sterculia.

If your anal fissure isn’t healing, your GP may prescribe: 

• Anal fissure cream — a local anaesthetic applied directly to your anus before passing a stool to block any pain in this area; this should only be used for short amounts of time to avoid irritating the skin around your anus
• Laxatives or medication to relax the muscles in your anus
• Steroid medication to reduce swelling around your anal fissure — this can also help reduce itching and pain

If you regularly have anal fissures, your doctor may recommend surgery. There are a number of surgical procedures that can successfully treat anal fissures. However, these procedures can increase your risk of temporary or permanent loss of bowel control (bowel incontinence). Your doctor will discuss your options with you.

Children receive the same treatments for anal fissures as adults. However, they are more likely to resist the urge to pass a stool due to discomfort. A doctor may, therefore, prescribe them laxatives to soften the stools while the fissure heals.

Most anal fissures heal in 1–2 weeks. However, if your anal fissure does not heal in this time, your doctor may suggest further treatments. These treatments relax the anal sphincter muscle, which increases blood supply to the anus and therefore aids healing: 

• Botulinum toxin 
• Calcium channel blockers
• Glyceryl trinitrate ointment — this is effective in six out of 10 cases
• Minor surgery to make a small cut in the anal sphincter — this is effective in nine out of 10 cases