Anal Fissure

Introduction

An anal fissure is a small tear or split in the thin, sensitive lining of the anal canal — the short passage at the very end of the bowel. Although the tear itself is usually tiny, it can cause sharp, intense pain during and after bowel movements, sometimes accompanied by a small amount of bright red bleeding. The pain can feel out of proportion to the size of the problem, and many people describe it as feeling like passing broken glass.

If you are reading this, you have most likely been told you have an anal fissure, or you have had the symptoms long enough to recognise the pattern. This article walks through what an anal fissure is, why it happens, how it is treated, and what to expect from healing — whether your fissure is recent and likely to settle with simple measures, or longer-standing and needing more active treatment.

Anal fissures are extremely common. They affect people of all ages, from infants to older adults, and across genders. Most are not serious and heal within a few weeks. A smaller number become chronic and need medical or surgical treatment to heal fully.

What Is an Anal Fissure?

The anal canal is lined by a delicate tissue called anoderm. A fissure is a linear tear in this lining, usually running lengthways along the canal. Most fissures occur in the midline at the back (the posterior midline) — this is the area with the poorest blood supply, which is part of why fissures here can be slow to heal. A smaller number occur in the front (anterior midline), more often in women, particularly after childbirth.

Doctors usually classify fissures by how long they have been present:

• Acute anal fissure: A fissure present for less than about six to eight weeks. It typically looks like a fresh tear with clean edges.
• Chronic anal fissure: A fissure that has not healed after six to eight weeks, or one that keeps recurring. Chronic fissures often have additional features — thickened edges, exposed muscle fibres at the base, a small skin tag at the outer end (called a sentinel pile), and a swollen bump (hypertrophied papilla) at the inner end.

Fissures that occur away from the midline, or that look unusual, raise the possibility of an underlying condition such as Crohn's disease, infection, or rarely a tumour. Your doctor will consider these possibilities during examination.

Causes and Risk Factors

An anal fissure usually starts with a mechanical injury to the lining of the anal canal. Common triggers include:

• Hard, large, or dry stools — the most common cause. Straining to pass a hard stool can split the lining.
• Persistent diarrhoea — repeated loose stools can also irritate and tear the lining.
• Childbirth — vaginal delivery can cause anterior fissures.
• Anal intercourse or insertion of objects into the anus.
• Local trauma from medical procedures or examinations.

Once a fissure forms, a vicious cycle often develops. The tear causes pain, the pain triggers spasm of the internal anal sphincter (the ring of muscle that normally keeps the anus closed), the spasm reduces blood flow to the already poorly supplied area, and the reduced blood flow prevents healing. This is why simply waiting is often not enough for a chronic fissure to heal — the cycle has to be broken.

Conditions and factors that increase risk include:

• Chronic constipation or a low-fibre diet
• Inflammatory bowel disease, particularly Crohn's disease
• Previous anal surgery
• Pregnancy and the postpartum period
• Conditions associated with reduced anal blood flow
• Tuberculosis, HIV, syphilis, and other infections (in atypical fissures)

Signs and Symptoms

If you have been diagnosed with an anal fissure, the typical pattern of symptoms will already be familiar. Recognising whether your symptoms are improving, persisting, or returning is what matters most now.

Common features of an anal fissure include:

• Sharp pain during bowel movements, often described as cutting or tearing.
• Pain that continues after the bowel movement, sometimes for minutes to hours. This lingering pain is often what makes the condition so distressing.
• Bright red blood, usually noticed on toilet paper or as streaks on the stool, rather than mixed through it.
• A visible tear, skin tag, or small lump near the anal opening.
• Itching or irritation around the anus.
• Fear of having a bowel movement, which can lead to holding stool in — making constipation and the fissure worse.

Symptoms that should prompt urgent review include heavy bleeding, fever, significant swelling or pus near the anus, severe pain not relieved by simple measures, or new symptoms in someone with a known history of inflammatory bowel disease.

Diagnosis

Anal fissure is mainly a clinical diagnosis. A careful history and a gentle external examination are usually enough.

During the visit, the doctor will:

• Ask about your bowel habits, the pattern and duration of pain, bleeding, and any related conditions.
• Gently separate the buttocks to inspect the anal opening. A fissure in the typical midline location, with characteristic features, often confirms the diagnosis without further tests.
• In an acute, painful fissure, a digital (finger) rectal examination or instrument examination may be deferred until the fissure has started to heal, because these can be very painful.

Further investigations may be considered when:

• The fissure is in an unusual location (not in the midline)
• There are multiple fissures
• The fissure looks atypical (irregular edges, undermined tissue, large or deep)
• There are other symptoms suggesting inflammatory bowel disease, infection, or a more serious condition
• Symptoms have not responded to standard treatment

In these cases, an examination under anaesthesia, a proctoscopy or sigmoidoscopy, biopsy of unusual tissue, or tests for infection may be performed. A colonoscopy is sometimes recommended if there is a concern about Crohn's disease, in older adults, or when bleeding cannot be fully explained by the fissure.

Treatment and Management

Treatment of an anal fissure follows a stepwise approach, often called a treatment ladder. The aim at every step is to break the cycle of pain, sphincter spasm, and poor blood flow so the lining can heal. The American Society of Colon and Rectal Surgeons (ASCRS) and other major societies generally recommend starting with conservative measures, then moving to medical therapy, then to procedural or surgical options if needed.

Conservative Treatment (First-Line for Acute Fissures)

Most acute fissures heal with simple measures aimed at softening the stool and reducing local irritation. Doctors typically recommend:

• Increasing dietary fibre — through fruits, vegetables, whole grains, and legumes — to produce softer, easier-to-pass stools.
• Drinking enough water across the day.
• Fibre supplements such as psyllium (ispaghula) husk, especially when dietary fibre alone is not enough.
• Stool softeners or osmotic laxatives for short periods if stools remain hard.
• Sitz baths — sitting in warm water for 10 to 15 minutes, often after bowel movements. Warm water relaxes the sphincter and provides symptom relief.
• Avoiding straining and not delaying bowel movements when the urge arises.
• Topical anaesthetic creams such as lidocaine for short-term pain relief, used sparingly.

With these measures, a high proportion of acute fissures heal within a few weeks. The same measures continue to play a role even when medical or surgical treatment is added later — they support healing and reduce recurrence.

Medical Therapy for Chronic Fissures

When a fissure has not healed after several weeks of conservative care, or is already chronic at first presentation, topical medications that relax the internal sphincter are commonly used. By reducing sphincter pressure, these medications improve blood flow to the fissure and allow it to heal.

Topical glyceryl trinitrate (GTN) or nitroglycerin ointment is a widely used first-line option. Applied to the anal area two or three times a day for six to eight weeks, it relaxes the sphincter. Healing rates in clinical studies are meaningfully higher than with placebo, although headache is a common side effect and some people stop treatment because of it. The headache usually improves with continued use or by adjusting how the ointment is applied.

Topical calcium channel blockers — usually diltiazem or nifedipine ointment — work in a similar way but tend to cause fewer headaches. Where available, they are often used as an alternative to GTN. Healing rates are broadly comparable.

Topical medications heal a substantial proportion of chronic fissures, but a meaningful number do not respond or recur after the course is finished. In those cases, the next step is usually botulinum toxin injection or surgery.

Botulinum Toxin Injection

Botulinum toxin (Botox) injection into the internal sphincter is a procedural alternative or addition to topical medication. The toxin temporarily weakens the sphincter muscle, reducing pressure for several weeks to a few months — long enough for the fissure to heal in many cases.

The injection is done in a clinic or day-care setting, sometimes under local or light sedation. Most people return to normal activity quickly. It can cause temporary minor leakage of gas or stool in a small number of patients, which usually resolves as the effect wears off.

Healing rates with botulinum toxin are intermediate between topical therapy and surgery. It is a useful option for people who have not responded to ointments, who cannot tolerate them, or who want to avoid surgery. Recurrence after the toxin wears off is possible.

Surgical Treatment

Surgery is generally considered for chronic fissures that have not healed despite adequate conservative and medical treatment, or sometimes earlier if symptoms are severe and the fissure has features unlikely to heal medically.

Lateral Internal Sphincterotomy (LIS) is the most established surgical treatment and is widely described in surgical guidelines as the gold standard for chronic anal fissure. A small, controlled cut is made in the lower portion of the internal anal sphincter, away from the fissure itself, to reduce sphincter pressure permanently. Healing rates are high — the majority of fissures heal within weeks of surgery, and recurrence is uncommon.

The main concern with LIS is a small risk of disturbance to continence — difficulty controlling gas or, more rarely, stool. This risk is influenced by how much of the sphincter is divided and by the patient's baseline sphincter function. Risk is generally higher in women (whose sphincters are shorter and may have been affected by childbirth), in older adults, and in people who already have some impairment of continence. Surgeons typically assess sphincter function carefully before recommending LIS.

Fissurectomy involves trimming away the chronic edges of the fissure and any associated skin tag or hypertrophied papilla, encouraging fresh healing. It is sometimes combined with botulinum toxin injection rather than with sphincterotomy — an option for patients in whom cutting the sphincter is considered too risky.

Advancement flap procedures involve covering the fissure with a flap of nearby healthy tissue. This is mainly used for fissures that have not healed after other treatments, for fissures in atypical locations, or in patients in whom sphincter division would be unsafe (for example, women with previous obstetric injury). It does not weaken the sphincter and so does not affect continence.

The choice between surgical options is individualised. It depends on the type and location of the fissure, baseline continence and sphincter function, previous treatments, and the surgeon's experience with each technique.

Treatment of Fissures Caused by Other Conditions

When a fissure is caused by an underlying condition — for example, Crohn's disease or an infection — treating that underlying condition is essential. Surgery on a Crohn's-related fissure can be problematic if the disease is not controlled, and the approach is generally more cautious. Specialist colorectal and gastroenterology input is important in these cases.

Lifestyle and Self-Care

Whatever treatment path is chosen, daily habits play a large role in healing and in preventing recurrence. Patients are commonly advised to:

• Build a fibre-rich diet — aiming for the levels typically recommended for adults (around 25–35 grams per day) through fruits, vegetables, whole grains, beans, and lentils. Increase fibre gradually to avoid bloating.
• Drink enough fluids — fibre works best with adequate water intake.
• Use a fibre supplement such as psyllium if dietary changes are difficult to maintain.
• Take warm sitz baths regularly during the healing phase — especially after bowel movements.
• Respond promptly to the urge to defecate rather than postponing.
• Avoid straining and limit time spent sitting on the toilet.
• Keep the anal area clean and dry, patting rather than wiping vigorously. Avoid harsh soaps and scented wipes.
• Avoid prolonged sitting where possible during the most painful phase.
• Stay physically active — regular movement supports healthy bowel function.

These measures are not optional add-ons. They are central to healing and, once the fissure has settled, to keeping it from coming back.

Monitoring and Follow-up

After starting treatment, your doctor will typically review progress at intervals appropriate to the treatment plan. Things they will be looking for include:

• Reduction in pain during and after bowel movements
• Resolution of bleeding
• Visible healing of the tear
• Any side effects from medications
• Bowel habit and continued use of fibre and fluids

If a fissure has not healed within the expected timeframe of a given treatment, the plan is usually escalated rather than continued indefinitely. Each step on the treatment ladder has a reasonable trial period beyond which other options are considered.

After successful healing — whether through conservative care, medical therapy, or surgery — ongoing attention to bowel habit is the main long-term task. Many people are able to return to normal life without specific follow-up, while those with risk factors for recurrence may benefit from periodic review.

Complications

Most anal fissures heal without lasting problems. Complications, when they occur, can include:

• Chronic fissure formation — the most common “complication,” in which an acute fissure fails to heal and becomes long-standing.
• Recurrence after initial healing, particularly if constipation or other underlying factors return.
• Skin tag or sentinel pile — a small flap of skin that can remain even after the fissure has healed. It is harmless but sometimes bothersome.
• Abscess or fistula formation — uncommon, but a chronic fissure can occasionally connect with the deeper tissues, leading to an infected cavity or an abnormal tract.
• Sphincter weakness and continence problems — mainly a concern after sphincterotomy, as described above.

Telling your doctor about new symptoms — particularly swelling, fever, pus, or worsening pain — is important so that complications can be identified and treated promptly.

Living with an Anal Fissure

Although an anal fissure is a small physical problem, it can have a disproportionate impact on daily life. Pain, fear of bowel movements, disrupted sleep, and reluctance to discuss the condition can all wear a person down. It is common to feel embarrassed or to delay seeking help. The condition is, however, very common and very treatable, and clinicians who manage it see fissures every week.

While treatment is underway, practical adjustments can help:

• Plan toilet visits when you are not rushed and can relax.
• Use a small footstool to bring the knees above the hips on the toilet — this position can reduce straining.
• Sit on a soft cushion or doughnut-shaped cushion if prolonged sitting is uncomfortable.
• Take pain-relief medication as advised by your doctor.
• Be patient. Even with good treatment, healing takes weeks, and pain typically improves gradually rather than suddenly.

Talk to your doctor about anything that is interfering with your daily life. Effective options exist at every stage.

Anal Fissures in Children

Anal fissures are common in infants and young children, particularly during the toddler years when toilet training, dietary changes, and constipation often coincide. Parents may notice bright red blood on the nappy, stool, or toilet paper, and the child may cry or resist bowel movements.

In children, the underlying problem is almost always constipation with hard stools. Treatment focuses on:

• Increasing fluid and fibre in the child's diet
• Using gentle laxatives or stool softeners as advised by the paediatrician — commonly an osmotic laxative such as polyethylene glycol — to keep stools soft for an extended period (often weeks to months)
• Encouraging regular, unhurried toilet visits
• Warm baths for comfort
• Sometimes a barrier ointment around the anus

Most childhood fissures heal completely with these measures. Surgery is rarely needed. Persistent or unusual fissures in a child — for example, multiple fissures, fissures away from the midline, or fissures with significant skin changes — should prompt a paediatric specialist review to rule out inflammatory bowel disease and other less common causes.

If you are a parent, the most important long-term step is preventing recurrence by maintaining soft stools for several months after healing, because the fear of pain can lead a child to hold stool, which restarts the cycle.

Preventing Recurrence

Once a fissure has healed, the priority shifts to keeping it from coming back. Recurrence is common when underlying habits return to what they were before. Strategies that reduce recurrence include:

• Maintaining a high-fibre diet long-term
• Drinking enough water consistently
• Using a fibre supplement if dietary intake is variable
• Treating constipation early rather than letting it build up
• Treating diarrhoea promptly and identifying causes if it is recurrent
• Avoiding prolonged straining and limiting time on the toilet
• Staying physically active

For people who have had a chronic fissure heal after medical or surgical treatment, these habits are particularly important — the area has demonstrated a tendency to tear and may do so again under similar conditions.

When to Seek Urgent Care

An anal fissure is rarely an emergency, but certain symptoms should prompt prompt medical attention:

• Heavy or persistent rectal bleeding
• Bleeding mixed through the stool (rather than only on the surface or on the paper)
• Fever, severe swelling, or pus near the anus — possible abscess
• Severe pain not relieved by simple measures
• Unexplained weight loss, change in bowel habit, or symptoms of anaemia (fatigue, breathlessness, pallor)
• New symptoms in someone with known inflammatory bowel disease

These features may indicate a complication, an underlying condition, or a different diagnosis that requires further evaluation.

Frequently Asked Questions

How long does an anal fissure take to heal?

Most acute fissures heal within four to six weeks with conservative measures. Chronic fissures, by definition, have not healed within six to eight weeks and usually need additional treatment. With topical medications or botulinum toxin, healing can take a further six to eight weeks. After surgery, the fissure typically heals within a few weeks, though full recovery and resolution of symptoms can take longer.

Is an anal fissure the same as a haemorrhoid?

No. A fissure is a tear in the lining of the anal canal, while haemorrhoids are swollen blood vessels in the anal area. Both can cause bleeding, but the pain pattern is different — fissures usually cause sharp pain during and after bowel movements, while haemorrhoids more often cause itching, a sensation of fullness, or painless bleeding. They can also occur together. Your doctor can usually distinguish them on examination.

Can an anal fissure heal on its own?

Yes — the majority of acute fissures heal on their own with attention to bowel habit, fibre, fluids, and warm sitz baths. Chronic fissures are less likely to heal without active treatment because the cycle of pain, sphincter spasm, and reduced blood flow keeps the area from healing.

Will I need surgery?

Most people do not need surgery. Surgery is generally reserved for chronic fissures that have not responded to conservative and medical treatment, and the decision is made in discussion with a colorectal surgeon after weighing the chances of healing against the small risk of continence problems. Several non-surgical options exist before surgery is considered.

Will lateral internal sphincterotomy affect my ability to control bowel movements?

For most patients, sphincterotomy does not cause lasting continence problems. A small proportion of patients experience minor difficulty controlling gas, and a smaller number have any difficulty with stool control. Risk is higher in women, older adults, and people with pre-existing sphincter weakness. Surgeons typically assess sphincter function before recommending the operation and may choose alternative procedures when the risk is judged to be higher.

Can pregnancy cause anal fissures?

Yes. Constipation during pregnancy and the mechanical effects of vaginal delivery can both contribute to fissures, particularly in the anterior midline. Most pregnancy-related fissures respond well to conservative measures. Treatment choices during pregnancy and breastfeeding are individualised and discussed with the obstetric team.

Is an anal fissure linked to cancer?

A typical anal fissure is a benign tear and is not cancer. However, some anal cancers can produce symptoms that mimic a fissure — particularly when the lesion looks unusual, is in an atypical location, or is not healing as expected. This is one of the reasons doctors examine non-healing or atypical fissures carefully and sometimes recommend biopsy.

Can spicy food cause anal fissures?

Spicy food does not cause fissures, but in some people it can irritate the anal area or trigger looser stools that aggravate an existing fissure. If you notice a clear pattern, reducing intake during the healing phase is reasonable.

Why does the pain continue for hours after a bowel movement?

The lingering pain is caused by spasm of the internal anal sphincter, which is triggered by the passage of stool over the fissure. The spasm can last for minutes to hours and is one of the most distressing aspects of the condition. Treatments that relax the sphincter — warm baths, topical medications, botulinum toxin, or sphincterotomy — address this directly.

Conclusion

An anal fissure is a small problem that can cause large amounts of pain and disruption. The good news is that it is highly treatable. Most acute fissures heal with attention to diet, fluids, and gentle care of the area. When fissures become chronic, an effective treatment ladder is available — topical medications, botulinum toxin injection, and, when needed, surgical options including lateral internal sphincterotomy, fissurectomy, and advancement flaps. The choice depends on the type of fissure, your overall health, sphincter function, and a conversation with your doctor.

Healing takes patience. Pain typically improves gradually, and even after the fissure has closed, the habits that support healing — soft, regular bowel movements and avoidance of straining — remain the most important long-term protection. With the right combination of treatment and self-care, most people with an anal fissure can expect full and lasting relief.