Anal Fissure

An anal fissure is a small tear in the lining of the anal canal. It commonly causes sharp pain during bowel motions, often described as a tearing or cutting sensation. Many patients also experience bright red bleeding on the toilet paper or in the toilet bowl.

Following a bowel motion, the internal anal sphincter muscle can go into spasm. This may cause a deeper aching, throbbing, or burning pain that can last from minutes to several hours. The muscle spasm can reduce blood flow to the fissure, making healing more difficult.

Anal fissures are common and are most often caused by trauma to the anal canal, including:

• Passing hard or large stools

• Constipation

• Straining during bowel motions

• Episodes of diarrhoea

• Childbirth

Less commonly, fissures may be associated with underlying conditions such as Crohn's disease.

Symptoms

Common symptoms of an anal fissure include:

• Sharp pain with bowel motions

• Burning or throbbing pain after opening the bowels

• Bright red bleeding

• A small lump or skin tag near the anus

• Itching or irritation around the anus

Acute vs Chronic Fissures

An acute fissure is generally present for less than 6 weeks and may heal with conservative treatment.

A chronic fissure is one that persists beyond 6 weeks or recurs frequently. Chronic fissures are often associated with ongoing sphincter spasm and reduced blood flow, making spontaneous healing less likely.

Assessment

Anal fissures are often diagnosed based on symptoms and examination. In many cases, the fissure can be seen during gentle inspection of the anal area.

Further investigation with sigmoidoscopy or colonoscopy may occasionally be recommended, particularly if there is rectal bleeding, atypical symptoms, or concern for another bowel condition.

Treatment

Treatment aims to reduce pain, relax the anal sphincter muscle, and allow the fissure to heal.

Conservative Management

Initial treatment commonly includes:

• Increasing dietary fibre

• Drinking adequate fluids

• Stool softeners or fibre supplements

• Avoiding straining

• Warm salt baths

These measures help soften bowel motions and reduce further trauma to the fissure.

Topical Treatments

Medicinal ointments may be prescribed to relax the anal sphincter and improve blood flow to the fissure. Common treatments include:

• Rectogesic (glyceryl trinitrate)

• Diltiazem cream

These treatments are often effective for acute fissures but may cause side effects such as headaches.

Some over-the-counter creams may provide temporary symptom relief but are generally not recommended for long-term use, particularly those containing steroid preparations which may impair healing.

Botox Injection

For chronic fissures that fail to heal with topical treatment, injection of botulinum toxin (Botox) into the anal sphincter may be recommended. Botox temporarily relaxes the muscle and can promote healing.

Surgery

Persistent or recurrent fissures may require a procedure which involves partially dividing a portion of the internal anal sphincter muscle to reduce spasm and improve blood flow to the fissure.