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HealthInfo Waitaha Canterbury

Anal fissure (tear)

Piere tou

An anal fissure is a small split or tear in the skin around your anus. These are very common and can occur from infancy through to adulthood, but mostly happen between the ages of 15 and 40.

Causes of an anal fissure

Damage to the skin around your anus is the most common reason why an anal fissure develops. It can happen when you pass a hard constipated stool (poo) and your ring of muscle (anal sphincter) is forced to open too quickly. If you have tight muscles around your anus, you may be more prone to anal fissure.

Another cause of anal fissure is diarrhoea (runny poo).

It can also happen during birth if your anus gets stretched as the baby’s head is delivered.

People with the bowel condition Crohn’s disease can also be at risk.

An anal fissure is a curable problem and doesn't go on to form cancer.

Symptoms of an anal fissure

The most common symptoms include:

If you have any of these symptoms, you need to visit your general practice team. It's always important to tell your general practice team if you're bleeding from your anus to rule out more serious causes.

Diagnosing an anal fissure

Your general practice team will assess your symptoms and look at the skin around your anus to make a diagnosis.

If a fissure is not visible but you have symptoms such as bleeding, your general practice team may arrange some tests.

Treating an anal fissure

Most fissures can be treated simply and heal within a few weeks.

Simple treatments you can try include:

Your general practice team may prescribe a cream containing a local anaesthetic to relieve your discomfort. Using this before going to the toilet can make it more comfortable to go.

If these measures do not work and your anal fissure gets worse, you may need further treatment. This often happens if you have ongoing spasm (contraction) of your anal sphincter muscle, which can reduce the blood flow to your skin around your anus and stop the fissure from healing. Treatment can either be medical with topical creams or surgical.

Medical treatments

As well as the simple measures mentioned above, your either may prescribe a cream to help relax your anal sphincter muscle. The first option is likely to be glyceryl trinitrate cream (Rectogesic), which relaxes the anal sphincter muscle and allows more blood flow into the skin to allow your fissure to heal. This doesn't help everyone but it's worth trying first.

The other cream that could be prescribed contains diltiazem. There is a charge for this as it is not subsidised by the government.

Surgical treatments

If the treatments above have not helped, your surgeon could either give you an injection of Botox (botulinum toxin) or make a small cut in your anal sphincter muscle (sphincterotomy). Both methods relax the anal sphincter muscle, give pain relief and allow the fissure to heal. The surgical cut works best to manage anal fissure in the long-term.

Risks of general surgery

Having surgery involves some risks but these are usually outweighed by the benefits. Your surgeon will discuss the likely risks with you.

It's important that you take adequate pain relief and keep your bowel motions soft to make them easier to pass while your anal area is healing.

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Written by HealthInfo clinical advisers. Last reviewed July 2022.


Page reference: 52907

Review key: HIANF-18611