What is Anal Fissure?

An anal fissure is a tear in the lining of the anus, usually caused by passing hard stools or straining during bowel movements. It is a common condition in Singapore and can affect both adults and children. Anal fissures may be acute (short-term) or chronic (persisting for more than 6 weeks).

How Anal Fissures Develops

An anal fissure occurs when the delicate skin around the anal canal is stretched beyond its limit. This often happens during constipation, straining or trauma to the anal area. When a tear forms, the surrounding muscles may tighten or spasm in response, reducing blood flow to the area and making healing slower. Over time, this cycle can cause persistent pain and delayed recovery.

Signs and Symptoms

Patients with anal fissures commonly notice:

Sharp pain during bowel movements, often described as “cutting” or “tearing”
Bright red blood on toilet paper or stool
A visible small tear near the anus
Itching or irritation around the anal area
A skin tag near the fissure (more common in chronic fissures)

If left untreated, chronic anal fissures may lead to persistent pain, recurrent bleeding, or infections.

Causes and Risk Factors

Common causes and factors that increase the risk of anal fissures include:

Constipation and hard stools
Straining during bowel movements
Chronic diarrhoea
Low fibre intake
Pregnancy or childbirth
Previous anal injury or surgery
Inflammatory bowel disease, such as Crohn’s disease

Managing Anal Fissure

Treatment focuses on relieving symptoms, promoting healing, and preventing recurrence. Most anal fissures improve with early care, and only a minority require surgery.

Treatment Options

Management usually begins with simple, non-surgical measures:

Maintaining a high-fibre diet and drinking plenty of water
Using stool softeners as advised by a doctor
Taking warm sitz baths to relax the anal muscles
Applying prescribed topical medications to improve blood flow and reduce muscle spasms
Taking pain relief as needed

If symptoms persist, your doctor may recommend:

Botulinum toxin (Botox) injection to relax the anal sphincter
Lateral Internal Sphincterotomy (LIS), a well-established and effective surgery for chronic anal fissures, commonly performed in Singapore

Most patients recover well with the right treatment approach.

Prevention

To reduce the risk of anal fissures or prevent recurrence:

Maintain a high-fibre diet (fruits, vegetables, whole grains)
Drink 1.5–2 litres of water daily
Avoid excessive straining when passing motion
Respond promptly to the urge to pass stool
Maintain regular bowel habits
Manage chronic constipation or diarrhoea early

These habits help keep stools soft and prevent straining, which is one of the main triggers for anal fissures.

When to See a Doctor

Consult a doctor or colorectal specialist if you experience:

Persistent pain for more than a few days
Bleeding that recurs or becomes heavier
Difficulty passing stools despite home measures
Symptoms lasting more than 6–8 weeks
Signs of infection, such as fever, pus, or severe swelling

Early assessment helps relieve discomfort and prevents chronic fissures.

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Frequently Asked Questions

How long do anal fissures take to heal?

Most acute anal fissures heal within 4–6 weeks with conservative treatment. Chronic fissures may take longer or require procedural or surgical intervention.

Is an anal fissure dangerous if left untreated?

Anal fissures are usually not dangerous but can be very painful. If left untreated, they may become chronic, causing ongoing pain, muscle spasms, and a higher risk of infection. Early treatment can prevent complications.

What is the difference between an anal fissure and haemorrhoids?

Anal fissures are tears in the lining of the anus, while haemorrhoids are swollen veins. Both can cause bleeding, but fissures typically cause sharp pain during bowel movements. A doctor can help distinguish between the two.

Do I need surgery for my anal fissure?

Most people do not need surgery. Surgery is recommended only when symptoms persist despite proper medical therapy or if the fissure becomes chronic.

Is anal fissure surgery safe?

Lateral Internal Sphincterotomy (LIS) is a well-established and generally safe procedure used for chronic anal fissures. It is commonly performed as a day surgery in Singapore, with most patients returning home the same day.