Anal Fisssure

Learn more about Anal Fisssure

Anal Fissure

An anal fissure is a tear in the lining of the anal canal. It usually causes a sharp, tearing sensation when having a bowel motion. The underlying anal sphincter then goes into spasm, which causes a deeper, often severe pressure or throbbing sensation which can last minutes to hours.

The anal spasm is thought to prevent blood flow to the healing wound, thus the anal fissure may not heal on its own.

An acute fissure (present for less than 2-6 weeks) may improve with increased fluid and fibre intake, warm baths, and topical Rectogesic or Diltiazem cream. Other over the counter ointments may provide symptomatic relief, but are not recommended – they contain steroids which may prevent healing.

A fissure that is present longer than six weeks, or one that recurs, is considered a ‘chronic anal fissure’. This will not usually respond to topical creams and requires the injection of botox into the anal sphincter, or a small cut in the sphincter (called a lateral internal sphincterotomy) to relieve the pressure.

Anal fissure diagram

The tear results from initial trauma

An anal fissure is a tear in the lining of the anal canal, which may occur following the passage of a hard stool.
This can result in often severe pain with the passage of stool. The pain is typically ‘sharp’, ‘tearing’, ‘like passing glass’ or can be a deep-seated throbbing pain. The pain may last minutes to hours. There may be an associated small amount of bright-red bleeding seen on the toilet paper.

The tear results from an initial trauma, which may be due to the passage of a hard stool, or the precipitating event may not be recognised. The pain results in muscle spasm, which exacerbates the pain. Furthermore, the muscle spasm impairs blood flow to the fissure, which in turn prevents healing. This allows a continuous cycle of tearing, pain, muscle spasm, lack of blood flow, poor healing and further tearing.

Treatment is aimed to break the cycle. Initial treatment may be topical creams to relax the muscle sphincter (e.g. topical GTN (Rectogesic) or topical diltiazem). Warm baths may help lower the muscle pain and provide symptomatic relief. Strong pain killers should be avoided as they can result in constipation leading to further trauma.

Unlikely to heal on its own

An acute fissure is unlikely to heal on its own if the symptoms have persisted after six weeks. At this stage, a more definitive relaxation of the sphincter muscle is required. This can be through an injection of botox to the sphincter, or with a minor surgical technique known as a sphincterotomy. The precise course of treatment needs to be tailored to the individual patient.

An anal fissure may be associated with other diseases (such as Crohn’s disease, an inflammatory condition), or the symptoms may reflect an alternative diagnosis. If the symptoms fail to respond to a single short-course of treatment (e.g. topical creams), then investigation is usually warranted. Particular warning symptoms include pain NOT associated with defecation, bleeding mixed in with the stool, new incontinence, a recent change in bowel habits, or a personal or family history of colonic polyps, bowel cancer or inflammatory bowel disease.

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