Anal Fissure: Symptoms, Causes & Treatment Options

What Is an Anal Fissure?

An anal fissure is a small tear or crack in the thin, moist tissue (mucosa) lining the anus. It typically occurs in the midline posteriorly (toward the tailbone) and causes severe, sharp pain during bowel movements, often accompanied by bright red blood on the stool or toilet paper.

The anal canal is the final portion of the digestive tract, a short tube about 4 centimeters long that connects the rectum to the outside of the body. It is lined with specialized tissue that is highly sensitive to touch, temperature, and pain. When this delicate lining is stretched beyond its capacity – typically by a hard or large stool – it can tear, creating an anal fissure.

Anal fissures are remarkably common, affecting approximately 1 in 350 people each year according to epidemiological studies. They occur equally in men and women and can affect people of all ages, including infants and children. However, the peak incidence occurs in young adults between 20 and 40 years of age. Understanding what causes anal fissures and how they heal is essential for effective treatment and prevention of recurrence.

The condition can be classified as either acute or chronic. Acute anal fissures are relatively fresh tears that have been present for less than 6-8 weeks. These typically appear as a simple linear crack in the anal mucosa and have excellent healing potential with conservative treatment. Chronic anal fissures have been present for longer than 6-8 weeks and develop distinctive features including raised edges, exposed internal sphincter muscle fibers, and often a sentinel pile (a small skin tag) at the external edge of the fissure.

The Anatomy Behind Anal Fissures

To understand why anal fissures develop and why they can be difficult to heal, it helps to understand the anatomy of the anal canal. The anal sphincter complex consists of two muscular rings: the internal anal sphincter (involuntary, always partially contracted) and the external anal sphincter (voluntary control). The internal sphincter maintains continence at rest and is the muscle most involved in anal fissure pathology.

Blood supply to the anal canal is critical for healing. The posterior midline of the anal canal, where most fissures occur, receives less blood flow than other areas. This relative ischemia (reduced blood supply) explains why tears in this location are more prone to becoming chronic and why treatments that improve blood flow are often effective.

Acute vs. Chronic Anal Fissure

The distinction between acute and chronic anal fissures is clinically important because it guides treatment decisions. Acute fissures typically heal with conservative measures alone, while chronic fissures often require more aggressive intervention.

What Are the Symptoms of an Anal Fissure?

The hallmark symptoms of an anal fissure are severe, sharp pain during bowel movements that can last for minutes to hours afterward, and bright red blood visible on the stool or toilet paper. Many people describe the pain as feeling like passing broken glass.

The symptoms of an anal fissure are often unmistakable due to their severity and their clear association with bowel movements. Understanding these symptoms helps differentiate anal fissure from other anorectal conditions like hemorrhoids, which have somewhat different symptom patterns.

Pain Characteristics

The pain from an anal fissure is typically described as sharp, cutting, or tearing in quality. It begins during the passage of stool and can be excruciating – many patients describe it as one of the most intense pains they have experienced. Unlike some other conditions, the pain from an anal fissure is directly triggered by the mechanical stretch of the bowel movement passing over the tear.

What makes anal fissure pain particularly burdensome is its duration. After the initial sharp pain during defecation, many people experience a second wave of pain caused by sphincter muscle spasm. This spasm-related pain can last from several minutes to several hours after the bowel movement, significantly impacting quality of life. Some patients report that sitting becomes uncomfortable, and they may avoid bowel movements out of fear of the pain – which unfortunately leads to constipation and worsens the condition.

Bleeding

Bleeding from an anal fissure is typically bright red and appears on the surface of the stool or on the toilet paper after wiping. The amount is usually small – streaks or spots rather than large quantities. This is because the blood comes from the superficial tear in the anal lining rather than from deeper blood vessels. The bleeding occurs during or immediately after bowel movements and typically stops on its own.

It's important to note that while anal fissure is a common cause of rectal bleeding, other conditions can cause similar symptoms. Any unexplained rectal bleeding should be evaluated by a healthcare provider, particularly in people over 40 or those with risk factors for colorectal disease.

Other Common Symptoms

• Visible tear: Sometimes the fissure can be seen as a small crack when the buttocks are gently spread apart
• Skin tag: A small skin tag (sentinel pile) may develop at the outer edge of a chronic fissure
• Itching: Some people experience itching around the anus, particularly as the fissure begins to heal
• Spasm: A feeling of tightness or cramping in the anal area, especially after bowel movements
• Discharge: Occasionally, there may be a small amount of mucus discharge

What Causes Anal Fissures?

The most common cause of anal fissure is constipation and the passage of hard, dry stools that stretch and tear the anal lining. Other causes include chronic diarrhea, childbirth, inflammatory bowel disease, and anal trauma. Understanding the cause is essential for preventing recurrence.

Anal fissures develop when the anal mucosa is stretched beyond its capacity and tears. While the immediate cause is mechanical trauma, several underlying conditions and factors predispose people to developing fissures.

Constipation: The Primary Culprit

Constipation is by far the most common underlying cause of anal fissures, responsible for the majority of cases. When stools become hard and dry due to inadequate fiber intake, insufficient fluid consumption, or delayed defecation, they require more force to pass. The straining involved and the larger diameter of hard stools create excessive pressure on the anal canal, leading to tissue tearing.

The relationship between constipation and anal fissure is bidirectional. Constipation causes fissures, but the pain from a fissure often leads people to avoid or delay bowel movements, which worsens constipation. This creates a self-perpetuating cycle that must be addressed in treatment.

Chronic Diarrhea

While constipation is more commonly associated with anal fissures, chronic diarrhea can also cause them. Frequent bowel movements irritate the anal lining, and the acidic nature of loose stools can break down the protective mucosa. People with conditions causing chronic diarrhea, such as irritable bowel syndrome (IBS), lactose intolerance, or infectious diarrhea, may develop anal fissures.

Childbirth

Vaginal delivery, particularly with prolonged pushing or delivery of a large baby, can cause anal fissures. The pressure and stretching during childbirth can traumatize the anal canal. Postpartum constipation, which is common due to dehydration, iron supplements, and fear of painful bowel movements after delivery, further increases the risk.

Inflammatory Bowel Disease

Patients with Crohn's disease and ulcerative colitis have an increased risk of anal fissures. In Crohn's disease, fissures may be atypical – occurring in locations other than the posterior midline or being multiple. These fissures can be more difficult to heal and may require treatment of the underlying inflammatory condition.

Other Causes and Risk Factors

• Anal trauma: Insertion of foreign objects, medical procedures (like colonoscopy), or anal intercourse
• Reduced anal blood flow: Conditions affecting circulation, previous anal surgery
• Sexually transmitted infections: HIV, syphilis, herpes, and chlamydia can cause anal ulceration
• Anal cancer: Rarely, what appears to be a non-healing fissure may be malignancy
• Decreased muscle tone: After certain surgeries or with aging

How Can I Treat an Anal Fissure at Home?

Most acute anal fissures heal within 4-6 weeks with home treatment including sitz baths 2-3 times daily, increasing fiber intake to 25-35 grams daily, drinking plenty of water, using stool softeners if needed, and applying over-the-counter pain-relieving creams before and after bowel movements.

Conservative treatment is the first-line approach for acute anal fissures and is successful in healing approximately 80-90% of cases. The goals of self-care are to keep stools soft, minimize trauma during bowel movements, promote healing, and reduce pain.

Sitz Baths: The Foundation of Home Treatment

A sitz bath involves sitting in warm water that covers the hips and buttocks. The warmth relaxes the anal sphincter muscle, improving blood flow to the fissure and reducing spasm-related pain. This is one of the most effective and immediate interventions for symptom relief.

To take a sitz bath, fill a bathtub with 3-4 inches of warm (not hot) water, or use a specialized sitz bath basin that fits over your toilet. Sit in the water for 10-20 minutes, allowing the warmth to penetrate the area. For best results, take sitz baths 2-3 times daily, and always after bowel movements when pain is typically most severe. Pat the area dry gently afterward rather than rubbing.

Dietary Changes: Fiber and Fluids

Increasing dietary fiber is crucial for softening stools and preventing the constipation that causes and perpetuates anal fissures. Adults should aim for 25-35 grams of fiber daily. Good sources include whole grains, fruits, vegetables, legumes, and bran. If you're not accustomed to a high-fiber diet, increase intake gradually over 2-3 weeks to minimize bloating and gas.

Fiber supplements like psyllium husk (Metamucil), methylcellulose (Citrucel), or wheat dextrin (Benefiber) can help reach fiber goals if dietary sources are insufficient. These should be taken with plenty of water – fiber without adequate hydration can actually worsen constipation.

Adequate fluid intake is equally important. Aim for at least 8 glasses of water daily. Warm fluids in the morning can help stimulate bowel movements. Limit caffeine and alcohol, which can have dehydrating effects.

Stool Softeners

If dietary changes don't produce sufficiently soft stools, over-the-counter stool softeners can help. Docusate sodium (Colace) draws water into the stool, making it softer and easier to pass. Osmotic laxatives like polyethylene glycol (MiraLAX) can also be used. Follow package directions and don't use stimulant laxatives long-term without medical guidance.

Topical Treatments

Over-the-counter pain-relieving ointments and suppositories designed for hemorrhoids can provide temporary relief from anal fissure pain. Products containing lidocaine (a local anesthetic) or hydrocortisone (reduces inflammation) can be applied before and after bowel movements. Apply a thin layer externally and just inside the anal opening.

Some people find petroleum jelly or barrier creams helpful for protecting the fissure during bowel movements. These create a lubricating layer that reduces friction and trauma.

Bathroom Habits

Don't delay bowel movements when you feel the urge. Holding in stool leads to water reabsorption and harder stools. Avoid straining – if a bowel movement doesn't come within a few minutes, get up and try again later rather than forcing. Use a footstool to elevate your feet while sitting on the toilet, which positions the body in a more natural squatting posture that eases passage.

When Should You See a Doctor for an Anal Fissure?

See a doctor if anal pain persists despite 4-6 weeks of home treatment, if you have rectal bleeding without a known cause, if pain is severe enough to interfere with daily activities, if you notice signs of infection, or if you have a condition like inflammatory bowel disease that requires specialized care.

While most acute anal fissures heal with conservative care, certain situations warrant medical evaluation. Understanding when to seek professional help ensures you receive appropriate treatment and that other conditions aren't missed.

Reasons to Consult a Healthcare Provider

• Persistent symptoms: Fissure hasn't healed after 4-6 weeks of proper self-care
• Unexplained bleeding: Rectal bleeding without a known cause, or bleeding that seems different from previous episodes
• Severe pain: Pain that significantly impacts your daily activities, sleep, or quality of life
• Signs of infection: Fever, increasing pain, redness spreading beyond the immediate area, or pus discharge
• Underlying conditions: Crohn's disease, ulcerative colitis, HIV, or other conditions affecting immune function or healing
• Atypical features: Fissure not in the typical posterior midline location, multiple fissures, or unusually large tears
• Recurrence: Fissures that keep coming back despite preventive measures
• Age over 50: New symptoms in this age group warrant evaluation to rule out other conditions

What to Expect at Your Appointment

Your doctor will take a detailed history about your symptoms, bowel habits, diet, and any relevant medical conditions. The physical examination typically involves a visual inspection of the anal area, which often reveals the fissure without the need for internal examination. However, a gentle digital rectal examination may be performed once acute pain has subsided.

In some cases, further evaluation with an anoscopy (examination using a short, lighted tube) or flexible sigmoidoscopy may be recommended, particularly if the diagnosis is uncertain or to rule out other conditions. These procedures are usually deferred until pain is better controlled.

How Do Doctors Treat Chronic Anal Fissures?

Chronic anal fissures that don't heal with conservative care can be treated with prescription topical medications like nitroglycerin or diltiazem cream (50-65% healing rate), Botulinum toxin (Botox) injections (60-80% success), or lateral internal sphincterotomy surgery (>90% healing rate).

When self-care measures fail to heal an anal fissure, or when the fissure has become chronic, medical treatments become necessary. The goal of medical therapy is to reduce internal sphincter muscle pressure, improve blood flow to the fissure, and allow healing to occur. Treatment progresses in a stepwise fashion, starting with topical medications and advancing to more invasive options if needed.

Topical Medications

Topical nitroglycerin (glyceryl trinitrate) was the first medical therapy proven effective for chronic anal fissure. Applied as a 0.2-0.4% ointment to the anal margin 2-3 times daily, it works by releasing nitric oxide, which relaxes the internal sphincter muscle and increases blood flow. Studies show healing rates of 50-65% over 6-8 weeks of treatment. The main side effect is headache, which affects about 20-30% of patients and may limit tolerability.

Topical calcium channel blockers like diltiazem (2%) or nifedipine cream work similarly by relaxing smooth muscle. These may cause fewer headaches than nitroglycerin and have similar efficacy. They are applied 2-3 times daily for 6-8 weeks.

PTNS (Percutaneous Tibial Nerve Stimulation)

A newer treatment option involves electrical stimulation of the tibial nerve near the ankle, which sends signals to the nerves controlling the pelvic floor and anal sphincter. PTNS reduces sphincter spasm, decreases swelling, and improves blood flow to promote healing. Treatment sessions last about 30 minutes and typically 10 sessions are needed. A small needle is inserted near the ankle and connected to a device that delivers mild electrical impulses. The procedure is not painful, though some find the needle insertion briefly uncomfortable. Some numbness or tingling in the foot may occur for about 30 minutes after treatment.

Botulinum Toxin (Botox) Injection

Botulinum toxin injection into the internal anal sphincter causes temporary paralysis of the muscle, reducing spasm and allowing the fissure to heal. The procedure is performed in an office setting with local anesthesia. Success rates range from 60-80%, and effects last 2-3 months, usually long enough for the fissure to heal. Side effects can include temporary mild fecal incontinence in a small percentage of patients, which typically resolves as the toxin wears off.

Surgical Treatment: Lateral Internal Sphincterotomy

For fissures that fail medical management, lateral internal sphincterotomy (LIS) is the gold standard surgical treatment. This procedure involves making a small cut in the internal anal sphincter muscle to permanently reduce its resting pressure. It's typically performed as a day surgery procedure under local or general anesthesia.

LIS has the highest success rate of all treatments, with healing rates exceeding 90-95%. The procedure has been performed for decades with well-established safety and efficacy. The main concern is the risk of fecal incontinence, which occurs in about 5-10% of patients – typically limited to occasional minor soiling or difficulty controlling gas, and usually temporary. This risk must be weighed against the benefits, and the procedure is generally avoided in patients with pre-existing continence issues.

Other Surgical Options

Alternative surgical approaches include anal advancement flaps, which cover the fissure with healthy tissue, and fissurectomy (removing the fissure itself). These are typically reserved for specific situations, such as patients with continence concerns or failed sphincterotomy.

How Can You Prevent Anal Fissures?

Prevent anal fissures by maintaining soft stools through a high-fiber diet (25-35g daily), drinking adequate fluids, exercising regularly, not delaying bowel movements, avoiding straining, and treating constipation promptly. These measures also help prevent recurrence after healing.

Prevention of anal fissures centers on avoiding the conditions that cause them – primarily constipation and hard stools. The same dietary and lifestyle measures used to treat fissures are equally important for prevention, especially in people who have had previous fissures.

Dietary Prevention Strategies

A diet rich in fiber is the cornerstone of fissure prevention. Fiber absorbs water and adds bulk to stool, making it softer and easier to pass without straining. Include a variety of fiber sources in your diet:

• Whole grains: Oatmeal, whole wheat bread, brown rice, quinoa
• Fruits: Apples, pears, berries, oranges, prunes (especially effective)
• Vegetables: Broccoli, carrots, leafy greens, sweet potatoes
• Legumes: Beans, lentils, chickpeas
• Nuts and seeds: Almonds, chia seeds, flaxseeds

Aim for gradual changes if you're not used to a high-fiber diet, as sudden increases can cause bloating and gas. Increase fiber intake over 2-3 weeks to allow your digestive system to adapt.

Hydration

Water is essential for fiber to work properly. Without adequate hydration, fiber can actually worsen constipation. Drink at least 8 glasses of water daily – more if you're physically active, in hot weather, or consuming high amounts of fiber. Warm beverages in the morning can help stimulate bowel movements naturally.

Exercise and Activity

Regular physical activity promotes healthy bowel function by stimulating intestinal contractions. Aim for at least 30 minutes of moderate exercise most days of the week. Even daily walking can make a significant difference in bowel regularity.

Healthy Bathroom Habits

Respond promptly when you feel the urge to have a bowel movement – delaying leads to harder stools as water is reabsorbed. Don't strain or spend excessive time on the toilet. Using a footstool to elevate your feet while sitting (simulating a squatting position) can make defecation easier and reduce straining.

Treating Constipation Promptly

If constipation occurs despite dietary measures, treat it promptly with over-the-counter stool softeners or osmotic laxatives rather than allowing it to persist. Early intervention prevents the hard stools that cause fissures.

Frequently Asked Questions