Anal Fissure

An anal fissure is a small, painful tear or ulcer in the lining of the anal canal, specifically in the squamous epithelium (anoderm) located just inside the anus. These tears are classified as acute if they have been present for less than 6-8 weeks, appearing as a fresh, superficial cut. If a fissure persists for more than 6-8 weeks, it is considered chronic, often becoming deeper with raised edges and sometimes developing secondary features like an exposed internal anal sphincter, a small skin tag (sentinel pile), or a hypertrophied anal papilla. The majority of anal fissures, known as primary fissures, are caused by a combination of local trauma, such as passing hard stools, and increased tension in the internal anal sphincter. This muscle spasm reduces blood flow to the area, hindering healing and creating a cycle of pain, spasm, and poor blood supply. Secondary fissures are less common and result from an underlying medical condition like inflammatory bowel disease, infections, or previous anal surgery.

Symptoms

Severe, sharp, tearing, or burning pain during bowel movements.
Pain that can last for minutes to several hours after a bowel movement.
Small amounts of bright red blood on the stool surface or toilet paper.
Anal itching (pruritus ani).
A palpable lump or skin tag (sentinel pile) at the edge of the anus, often seen with chronic fissures.
Malodorous discharge (less common).

Causes & Risk Factors

Local trauma to the anal lining, most commonly from passing hard, dry stools.
High resting pressure of the internal anal sphincter, leading to muscle spasm and reduced blood flow (ischemia) to the anal area, which impairs healing.
Inflammatory bowel disease, particularly Crohn's disease.
Certain infections, such as HIV, syphilis, tuberculosis, or herpes simplex virus.
Previous anal surgery.
Malignancy, including squamous cell carcinoma or leukemia.
Trauma from childbirth or anal intercourse.
Constipation and straining during bowel movements.
Passing hard or large stools.
Chronic diarrhea.
Childbirth or vaginal delivery, due to trauma to the perineum.
Inflammatory bowel disease (IBD), especially Crohn's disease.
Anal intercourse.
A diet low in fiber.
Inadequate fluid intake.
Certain bowel habits, such as prolonged sitting on the toilet or straining.
Age, as fissures are common in infants and young to middle-aged adults.
Underlying medical conditions like Crohn's disease, HIV, tuberculosis, or leukemia.
Pregnancy and the postpartum period.
Prior anal surgery that may cause scarring or sphincter dysfunction.

Diagnosis

A detailed discussion of your symptoms, including the nature of pain, presence of bleeding, and bowel habits.
Inquiry about risk factors such as inflammatory bowel disease, previous anal surgery, and sexual history.
Gentle visual inspection of the anal area, which is often sufficient to identify the tear.
Most fissures are found in the posterior midline of the anus, with about 10% occurring in the anterior midline, more commonly in women.
Digital rectal examination (DRE) and anoscopy are often avoided initially due to severe pain, but may be performed if pain allows or if the fissure is chronic.
Further investigations like sigmoidoscopy, colonoscopy, or biopsy are generally not needed for typical acute fissures but may be recommended for atypical features (e.g., lateral location, multiple fissures), if standard therapy fails, or if there is suspicion of an underlying condition like IBD or malignancy.
Diagnosis is confirmed by directly seeing a linear or elliptical tear in the anal lining.
A chronic fissure is diagnosed if it has been present for more than 6-8 weeks and has features like visible internal anal sphincter fibers, a sentinel skin tag, or a hypertrophied anal papilla.

Treatment Options

Increasing dietary fiber intake to 25-35 grams per day and fluid intake to 1.5-2 liters per day to soften stools.
Using fiber supplements like psyllium or methylcellulose.
Taking warm sitz baths for 10-20 minutes several times a day, especially after bowel movements, to help relax the anal sphincter.
Avoiding straining during bowel movements.
Topical glyceryl trinitrate (GTN) ointment (0.4% or 0.2%) to relax the anal sphincter, though it can cause headaches.
Topical calcium channel blocker creams (e.g., diltiazem 2% or nifedipine 0.2-0.5%) as an alternative to GTN, often with fewer side effects.
Botulinum Toxin A injection into the internal anal sphincter for patients who do not respond to or cannot tolerate topical medications.
Lateral Internal Sphincterotomy (LIS), a surgical procedure that involves a controlled division of a small part of the internal anal sphincter, considered the gold standard for refractory chronic fissures.
Fissurectomy with or without an anal advancement flap, another surgical option, particularly if there is no significant sphincter hypertonia or if there is a high risk of incontinence.

Frequently Asked Questions

What is the difference between an anal fissure and a hemorrhoid?

An anal fissure is a tear in the lining of the anal canal, causing sharp pain and usually a small amount of bright red blood. Hemorrhoids are swollen blood vessels in the rectum or anus, which can also bleed but typically cause less pain unless thrombosed (clotted).

Is the bleeding from an anal fissure dangerous?

Bleeding from an anal fissure is typically a small amount of bright red blood on the stool surface or toilet paper. While usually not dangerous, significant bleeding or any bleeding not associated with defecation should be evaluated by a doctor as it could indicate a different condition.

How long does it take for an anal fissure to heal?

Acute anal fissures often heal spontaneously with conservative measures within a few weeks. Chronic fissures, however, are less likely to heal without medical or surgical intervention.

What are the side effects of the creams (GTN, diltiazem) used for treatment?

Topical glyceryl trinitrate (GTN) can commonly cause headaches. Topical calcium channel blockers like diltiazem or nifedipine generally have fewer side effects.

Will I need surgery for my anal fissure?

Surgery is typically considered for chronic anal fissures that have not responded to conservative measures and medical therapies like topical creams or botulinum toxin injections. It is usually a third-line treatment option.

What are the risks of surgery for an anal fissure?

The most common surgical procedure, Lateral Internal Sphincterotomy (LIS), has a small but permanent risk of incontinence (difficulty controlling gas, liquid stool, or minor soiling). Other risks include bleeding, infection, and delayed healing.

Can anal fissures come back after they heal?

Yes, anal fissures can recur, especially after medical therapy. Recurrence is often linked to a return of constipation or passing hard stools. Adhering to lifestyle modifications is important for prevention.

Is it safe to have an anal fissure during pregnancy?

Anal fissures are common during the third trimester and postpartum period. Treatment during pregnancy primarily focuses on conservative measures like increasing fiber and fluids, and warm sitz baths. The use of topical medications should be discussed with your healthcare provider, and surgery is generally avoided during pregnancy.

How does diet affect my anal fissure?

A diet high in fiber (25-35 grams per day) and adequate fluid intake (1.5-2 liters per day) are crucial. These help soften stools, making them easier to pass and reducing trauma to the anal canal, which is key for healing and prevention.

What are sitz baths and how do they help?

Sitz baths involve sitting in warm water for 10-20 minutes, several times a day, especially after bowel movements. The warm water helps to relax the internal anal sphincter muscle, which can reduce pain and improve blood flow to the fissure, promoting healing.

Is an anal fissure a sign of cancer?

While most anal fissures are not a sign of cancer, certain features like fissures that are multiple, very large, painless, or located off the midline (lateral position) can be red flags that suggest an underlying condition, including malignancy. Your doctor may recommend further investigation if these atypical features are present.

Why is my anal fissure not healing?

A fissure may not heal if it has become chronic (present for more than 6-8 weeks). This is often due to persistent high tension in the internal anal sphincter, which reduces blood flow to the area, creating a cycle of pain, muscle spasm, and poor healing.

What makes a fissure 'chronic'?

An anal fissure is considered chronic if it has been present for more than 6-8 weeks. Chronic fissures often have deeper tears with raised edges and may develop secondary features such as exposed internal anal sphincter fibers, a sentinel skin tag, or a hypertrophied anal papilla.

What is a sentinel pile or skin tag?

A sentinel pile, also known as a sentinel skin tag, is a small lump of skin that can form at the outer edge of an anal fissure, particularly with chronic fissures. It is a common secondary feature of a long-standing tear.

Does botox injection for anal fissure work?

Botulinum Toxin A injections into the internal anal sphincter are an effective treatment option for chronic anal fissures, especially for patients who have not responded to or cannot tolerate topical medications. Healing rates typically range from 60-80%.

What is a lateral internal sphincterotomy (LIS)?

Lateral Internal Sphincterotomy (LIS) is a surgical procedure considered the gold standard for chronic anal fissures that haven't healed with other treatments. It involves a controlled, small cut in the distal part of the internal anal sphincter muscle to reduce its tension, improve blood flow, and promote healing.

Will I become incontinent after surgery?

Lateral Internal Sphincterotomy (LIS) carries a small but permanent risk of developing some degree of incontinence, most commonly for gas or minor soiling, or liquid stool. Your surgeon will discuss this risk with you.

Can children get anal fissures?

Yes, anal fissures are common in infants and young children, often due to constipation and the passage of hard stools.

Should I use stool softeners or laxatives?

The primary goal is to achieve soft, easily passed stools. Increasing dietary fiber and fluid intake is the first step. Fiber supplements can act as stool softeners. If constipation persists, your doctor may recommend specific stool softeners or laxatives.

What should I do if the pain is unbearable?

If you experience severe, intractable pain from an anal fissure, you should seek medical attention. This may be an indication for referral to a specialist for more advanced treatment options.

When should I see a colorectal specialist?

You should see a colorectal specialist if your anal fissure does not heal with conservative and initial medical therapy, if you have diagnostic uncertainty or atypical features, or if you are considering botulinum toxin injections or surgery.