An anal fissure is a tear or ulcer (open sore) that develops in the lining of the anal canal.
Type of anal fissure
Anal fissures can be classified as:
- Primary – where there is no obvious cause why the anal canal was damaged. It is difficult to prove for certain, but many experts believe that most cases of primary anal fissure occur following an episode of constipation, when a person tries to pass a particularly hard stool which damages the anal canal
- Secondary – where there is an obvious cause.Causes of secondary anal fissure include, pregnancy, inflammatory bowel disease (IBD), anal cancer, sexually transmitted infection (STI)
What are the symptoms?
Common symptoms of anal fissures include:
- A sharp pain or burning sensation when passing a stool (faeces )
- Noticing bright red blood on toilet paper or on the toilet seat
Diagnosing anal Fissure
To diagnose an anal fissure, your doctor will ask you about your symptoms and the type of pain that you have been experiencing. They may also ask you about your toilet habits.
If you have an anal fissure you will usually experience some pain when gentle pressure is applied on the edge of your anus. In order to confirm a diagnosis of an anal fissure, your doctor will usually need to carry out a physical examination. They will need to examine your anus by gently parting your buttocks. In most cases, your doctor will be able to see the fissure.
Treating anal Fissure
Like other small cuts or tears to the skin, an anal fissure will often heal by itself within a few weeks. However, you may require treatment to help ease the pain and discomfort that an anal fissure can cause.
There are a number of treatments that can encourage your anal fissure to heal, as well as easing your pain. These treatments are described below.
As an anal fissure can make it very painful for you to pass faeces (stools), your doctor will try to make the process easier for you by ensuring that your stools are soft. This will help you to pass stools more easily and with less pain and discomfort. Some of the ways that your stools can be softened are outlined below.
To keep your stools soft, you will usually be prescribed a laxative. Adults with an anal fissure will usually be prescribed a bulk-forming laxative. Bulk-forming
laxatives work by helping your stools to retain fluid, making them softer and denser.
Fluid and Fibre
As well as using laxatives, you should also increase the amount of fibre in your diet. Foods that are high in fibre include: wholegrain bread, brown rice, pasta, oats, beans, peas, lentils, grains, seeds, fruit, egetables
Adults should aim to eat at least 18g of fibre a day.
If you are increasing your fibre intake, you should do so gradually. A sudden increase can cause stomach cramps and make you produce more wind, leaving you feeling bloated. It is also important to make sure that you drink plenty of water. You should drink approximately 1.2 litres (six to eight glasses) of water a day, or more when you are exercising or when it is hot.
There are a number of medications that can be used to treat anal fissures, which are described below.
A topical medicine is one that you apply directly to the affected area. Topical anaesthetics work by desensitising (numbing) the skin, which in the case of an anal fissure will help to ease the sharp and severe pain that you may experience when passing stools.
Lidocaine is the most commonly prescribed topical anaesthetic. It either comes in the form of a gel or an ointment. Lidocaine is usually only used for one to two weeks because the fissure should start to heal within this time. It is usually applied shortly before passing a stool.
If you experience prolonged, burning pain after passing stools, you may be prescribed an analgesic (painkiller).
Calcium channel blockers
Calcium channel blockers are a type of medication usually used to treat high blood pressure (hypertension). However, it has also proved useful in treating cases of anal fissures in some people. Calcium channel blockers work by relaxing the sphincter muscle and increasing the blood supply to the site of the fissure. They are available in topical or tablet form.
Glyceryl trinitrate (GTN)
GTN works by expanding nearby blood vessels, which help increase the blood supply to the site of the fissure. The increase in blood supply should enable the fissure to heal more quickly.
GTN also reduces anal pressure. This should help to reduce the symptoms of pain. It comes in the form of an ointment and is applied directly to the anal area, usually every 12 hours. Headaches are a very common side effect of this type of medicine. Approximately 50% of people using GTN will experience a headache. Some people may also feel dizzy or light-headed after using GTN.
You will usually have to use GTN ointment for six to eight weeks, or until your fissure has completely healed.
There are a number of different surgical techniques that can be used to treat an anal fissure. These are discussed below.
- Internal sphincterotomy
An internal sphincterotomy is a type of surgery where the surgeon cut a section of the sphincter muscle. This helps to reduce the tension in the muscle, preventing further spasms of the sphincter and allowing the anal fissure to heal.
A fissurectomy is a surgical procedure where the anal fissure is surgically removed as well as the surrounding tissue.
- Advancement anal flaps
Advancement anal flaps are not usually recommended to treat primary anal fissures. Like a fissurectomy, this form of treatment does not address the underlying causes of an anal fissure.
Preventing anal fissure
It is not always possible to prevent an anal fissure. However, one of the best ways to prevent one from developing is to avoid becoming constipated.
To prevent constipation you should:
- Eat plenty of fibre, at least 18g a day
- Drink plenty of water, at least 1.2 litres (six to eight glasses a day) or more when you are exercising or when it is hot
- Do not ignore the urge to go to the toilet
- Keep active. A minimum of 30 minutes of physical activity a day, five times a week, is the recommended amount of activity that you should be doing