Anal fissure

Published by Bupa’s Health Information Team, November 2010.

This factsheet is for people who have an anal fissure, or who would like information about it.

An anal fissure is a small tear or ulcer (open sore) in the skin around the opening of the anus. It can cause severe pain, especially when opening the bowels.

About anal fissure

Anal fissure is a common condition. Although it can occur at any age, it’s most common in people aged 20 to 40. An anal fissure can be confused with piles (haemorrhoids) because the symptoms are similar.

Most anal fissures are at the rear of the anus – in line with the cleft of your buttocks. A fissure can also occasionally occur at the front of the anus.

Acute and chronic anal fissures

An anal fissure usually heals within six weeks (known as acute anal fissure). But if it persists for longer than six weeks, it’s known as a chronic anal fissure.

An acute illness is typically over quite quickly. A chronic illness is one that lasts a long time, sometimes for the rest of the affected person’s life. When describing an illness, the terms ‘acute’ and ‘chronic’ refer to how long a person has had it, not to how serious the condition is.

Symptoms of anal fissure

If you have an anal fissure, you may have the following symptoms.

• A sharp, searing or burning pain in or around your anus. This pain can last for a couple of hours after a bowel movement and is severe.
  
• A streak of blood when using toilet paper or drops of blood in the toilet bowl.
  
• A sentinel pile. This is a tag of skin that can develop on the edge of your anus below the fissure. A sentinel pile isn’t a haemorrhoid.

If you have these symptoms, you should see your doctor.

Complications of anal fissure

The main complication of anal fissure is that it fails to heal, resulting in a chronic anal fissure. This can happen if the tear extends into the ring of muscle that holds your anus closed (internal sphincter muscle) or if the pain causes the internal sphincter muscle to go into spasm. This can increase the pressure within your anus, and make it even harder to have a bowel movement. The more you strain, the less likely it is that the tear will heal.

A chronic anal fissure may require surgery to help it heal.

Causes of anal fissure

There are a number of reasons why you may develop an anal fissure. These include:

• straining during a bowel movement – often due to constipation
  
• recurrent or chronic diarrhoea
  
• Crohn’s disease
  
• sexually transmitted infection – when an infection in the skin around the anus causes a tear
  
• being in the third trimester of pregnancy
  
• childbirth
  
• diabetes
  
• human immunodeficiency virus (HIV) infection
  
• certain medicines (eg nicorandil)

Diagnosis of anal fissure

Your doctor will ask about your symptoms and medical history. He or she may examine the area by gently parting the buttocks. If your doctor can see the fissure, he or she will usually prescribe treatment.

If the tear isn’t visible, it’s important to make the correct diagnosis as other conditions can cause similar symptoms. Your doctor may refer you to a colorectal surgeon (a doctor who specialises in conditions that affect the bowel). At the hospital, a detailed examination can be done under anaesthesia to help reduce discomfort.

Treatment of anal fissure

To help an anal fissure to heal it’s important to stop straining during a bowel movement and manage the pain caused by the fissure. There are several treatment options.

Self-help

Making changes to your diet can help prevent constipation and make your faeces softer. You can do this by:

• eating a balanced diet with lots of fibre
  
• drinking enough fluid so that you don’t become dehydrated
  
• taking regular exercise

It may help to use a lubricant such as petroleum jelly around your anus before you have a bowel movement. Sitting in a warm bath after a bowel movement may relieve your discomfort.

Medicines

Your doctor may prescribe a laxative to soften the faeces (eg lactulose syrup). You can buy laxatives over the counter from a pharmacist without a prescription. However, it’s a good idea to see your GP before trying laxatives as there are different types of laxative that work in different ways. Your GP will prescribe you one that is most suited to treat your condition.

If you need pain relief, you can take over-the-counter painkillers such as paracetamol or ibuprofen.

Your GP may prescribe the following medicines to relieve the spasm of an anal fissure.

• Local anaesthetic (eg lidocaine). This may come as a cream, ointment or suppository and will completely block pain from the anus.
  
• Glyceryl trinitrate. This is a rectal ointment that will relax the internal anal sphincter muscle. This will reduce the spasm and improve the blood flow to your anus and help the fissure heal.
  
• Calcium channel blockers (eg diltiazem and nifedipine). These medicines act by relaxing part of the sphincter to reduce the spasm and the pressure in your anus. Studies of these treatments have produced mixed results, so you should ask your GP for advice. Calcium channel blockers aren’t currently licensed in the UK to treat anal fissures but they can be prescribed by doctors for ‘off-label’ use. This means the medicine is being used to treat a condition that it has hasn’t been licensed for and isn’t listed in the patient information leaflet that comes with the medicine. A doctor can legally prescribe outside the licence if he or she feels the medicine will be effective for you.

Always read the patient information leaflet that comes with your medicine and if you have any questions, ask your doctor or pharmacist for advice.

Surgery

Most anal fissures heal with the use of medicines or by changing your diet. However, if the anal fissure doesn’t get better, you may need anal fissure surgery.

The aim of surgery is similar to that of medicines – to relieve the pressure within your anus. This is usually done using a procedure called lateral internal sphincterotomy (LIS). A small cut is made in the internal sphincter muscle to stop it from going into spasm. This means you strain less when you go to the toilet and because of this, less stress is put on the fissure, giving it time to heal. The procedure is usually done under general anaesthesia. This means you will be asleep during the operation.

Increasingly, botulinum A toxin is being used by surgeons to produce a ‘chemical sphincterotomy’. Botulinum A toxin is injected into the internal sphincter muscle to help it relax. This is usually done under anaesthesia and the treatment effects last about three months – by which time it is hoped the fissure will have healed. Like calcium channel blockers, the use of botulinum toxin A is ‘off-label’.

Prevention of anal fissure

You can reduce your risk of anal fissure by preventing constipation. You can prevent constipation by eating a balanced diet rich in fibre, fruit and vegetables and drinking enough fluids combined with regular exercise.

If you have a condition that increases your risk of having an anal fissure, speak to your doctor. Your doctor will discuss with you how to best manage your circumstances and reduce your risk of having an anal fissure.

For answers to frequently asked questions on this topic, see FAQs.

For sources and links to further information, see Resources.