What is an anal fissure?
An anal fissure is a tear in the lining of anus. When a tear occurs, the internal anal sphincter typically goes into spasm. This can cause further tearing (as the spasm pulls the tissues apart) and pain, as well as reduced blood flow to the area (impairing healing).
Anal fissures are very common. Around one in five people are thought to develop a fissure during their lifetime. The real rate may be much higher and many people don’t report symptoms to their doctor.
What are the symptoms of anal fissures?
The most common symptoms of an anal fissure are:
- a sharp, stinging or burning pain during and after passing stool
- itchiness around the anus
- bleeding from the anus – you might see bright red blood on the surface of the stool, on the toilet paper or as drops in the toilet bowl
The bleeding is usually mild. But if the blood discolours the water in the toilet bowl, it can look like heavy bleeding.
These symptoms can occur with other anal conditions. It is important to report any symptoms to your doctor. Although anal fissures don’t lead to more serious problems, other conditions need to be ruled out.
What causes anal fissures?
Anal fissures are caused by injury to the anal canal. Injury can due to:
- passing a large stool
- trying to pass a hard stool (constipation)
- repeated/explosive diarrhoea
- childbirth
- receiving anal sex
People with other medical conditions, such as Crohn’s disease, may be more prone to anal fissures.
Some anal fissure experts believe that spasms of the internal anal sphincters may also cause tears.
How is an anal fissure diagnosed?
Anal fissures can usually be diagnosed based your symptoms and a physical examination. The physical examination involves gently parting your buttocks to see the anal area. Fissure can often occur at the 12 or 6 o’clock positions.
Occasionally, your doctor may further examine the area with:
- a digital rectal examination – where your doctor inserts a gloved, lubricated finger into the anal canal and feels for anything abnormal
- anoscopy – where a small tube with a light is inserted into the anus.
If the diagnosis is unclear, a colonoscopy by an anal fissure specialist may be needed.
How is are anal fissures treated?
Anal fissure treatments aim to relieve pain and spasm and to heal the fissure.
Most anal fissures heal within a few days or weeks without special treatment. These are acute anal fissures. An anal fissure that hasn’t healed after 8–12 weeks is a chronic fissure. This sort may need medical treatment.
Initial treatment involves resolving constipation, softening stools and reducing anal sphincter spasm.
Adding fibre to your diet
If you have an anal fissure, it’s best avoid hard stools that can stretch the anus and open the healing fissure. Increasing fibre in your diet is a good way to do this. Fibre works by absorbing water into the stool, which increases stool bulk and softens stool.
You can add fibre to your diet by eating more vegetables and fruits, or by using fibre supplements.
Laxatives
If your anal fissure is related to constipation, laxatives can be helpful.
Bathing the area
Immersing the anal area in warm water for 10–15 minutes two or three times daily can improve blood flow and relax the internal anal sphincter. You can use a special ‘sitz’ bath or you can fill a regular bath with 5–10 cm of warm water. Don’t use soap or fragrances in the water. A hand-held shower can be used to spray the area if you don’t have a bath.
It’s important to dry the anal area well after bathing. You might like to use a hair dryer on a low heat setting.
Topical medicine
Your doctor may prescribe medication that you apply to the anal area to increase blood flow and/or relax the internal anal sphincter.
Botulinum toxin ‘Botox’
If your anal fissure doesn’t improve with other treatments, your anal fissure specialist may recommend ‘Botox’. It can be injected into the internal anal sphincter muscle where it will cause a temporary paralysis. This will relieve pain but can result in mild anal leakage in some patients.
Surgery
Surgery is generally reserved for anal fissures that fail to heal after 1–3 months of medical therapy.
The most common procedure is a lateral sphincterotomy. This is where your anal fissure specialist makes a small cut in the internal anal sphincter, which relaxes it. It is done as a day procedure under general anaesthetic. The main risk with surgery is anal incontinence.
Your anal fissure specialist can discuss the benefits and risks of any treatment with you.