Anal Fissure: Causes, Symptoms & Treatment
📊 Quick Facts About Anal Fissure
💡 Key Takeaways About Anal Fissure
- Most common cause is constipation: Hard, dry stools tear the delicate lining of the anal canal
- Pain creates a vicious cycle: Pain causes muscle spasm, reducing blood flow and preventing healing
- Most heal without surgery: Warm sitz baths, fiber, and hydration help 60-80% of fissures heal
- Don't avoid bowel movements: Delaying makes constipation worse and prolongs healing
- Chronic fissures need medical treatment: Prescription ointments or surgery may be necessary after 6-8 weeks
- It's not the same as hemorrhoids: Though symptoms overlap, fissures and hemorrhoids are different conditions
What Is an Anal Fissure?
An anal fissure is a small tear or crack in the thin, moist tissue (mucosa) that lines the anus. This tear causes severe pain during bowel movements and often results in bright red blood on the stool or toilet paper. Anal fissures are common and can affect people of all ages, including infants and children.
The anal canal is the short tube at the end of the rectum through which stool passes when you have a bowel movement. The lining of this canal is delicate and can be easily torn when stretched beyond its normal capacity. When this tear occurs, it exposes the underlying muscle tissue to stool and bacteria, triggering intense pain and muscle spasms that can prevent healing.
Anal fissures are classified into two types based on how long they have been present. Acute anal fissures are recent tears that typically heal within 4-6 weeks with proper treatment. They appear as a fresh tear with clean edges. Chronic anal fissures are those that persist for more than 6-8 weeks despite conservative treatment. These often develop additional features such as a skin tag (sentinel pile) at the external edge and exposed internal sphincter muscle fibers at the base of the fissure.
The location of the fissure provides important diagnostic information. Approximately 90% of anal fissures occur in the posterior midline (toward the back), while about 10% occur in the anterior midline (toward the front). Fissures occurring in other locations may suggest underlying conditions such as Crohn's disease, tuberculosis, sexually transmitted infections, or cancer, and warrant further investigation.
The anus has two ring-shaped muscles (sphincters) that control bowel movements. The internal anal sphincter is involuntary and constantly contracted to maintain continence. When an anal fissure forms, the pain causes this muscle to spasm even more tightly, which reduces blood flow to the area and creates a cycle that prevents healing. This is why treatments often focus on relaxing this muscle.
How common are anal fissures?
Anal fissures are one of the most common anorectal problems, affecting approximately 10-15% of patients who visit colorectal clinics. They occur equally in men and women and can happen at any age. Infants often develop fissures during their first year of life, while in adults, they most commonly occur in young and middle-aged individuals. The true prevalence in the general population is difficult to determine because many people don't seek medical attention due to embarrassment or because symptoms resolve with self-care.
What Are the Symptoms of an Anal Fissure?
The hallmark symptoms of an anal fissure are severe, sharp pain during bowel movements and bright red blood on the stool or toilet paper. The pain often continues for minutes to hours after defecation. Other symptoms may include itching, a visible crack in the anal skin, and a small skin tag near the fissure.
The pain caused by an anal fissure is characteristically severe and has been described as feeling like "passing broken glass" or "being cut with a knife." This intense pain typically begins during the bowel movement and can persist for 30 minutes to several hours afterward. The severity of the pain often leads people to avoid or delay bowel movements, which paradoxically worsens constipation and makes the fissure worse.
The pain pattern in anal fissures is distinctive and helps differentiate them from other conditions. Initially, there is sharp, cutting pain as the stool stretches the fissure during passage. This may be followed by a brief period of relief, then a second wave of deeper, throbbing pain as the internal sphincter muscle goes into spasm. This secondary pain can last for hours and significantly impacts quality of life.
Bleeding from anal fissures
Bleeding from an anal fissure is typically bright red and separate from the stool. You may notice blood on the toilet paper when wiping, streaks of blood on the surface of the stool, or drops of blood in the toilet bowl. The amount of blood is usually small but can be alarming. It's important to note that other conditions, including hemorrhoids, inflammatory bowel disease, and colorectal cancer, can also cause rectal bleeding. If you experience rectal bleeding and don't know the cause, you should see a healthcare provider for evaluation.
Other symptoms to watch for
Beyond pain and bleeding, anal fissures may cause additional symptoms that affect daily life. Itching around the anus (pruritus ani) is common, often developing as the fissure begins to heal. A small lump or skin tag may form at the external edge of a chronic fissure, known as a sentinel pile. Some people experience a sense of incomplete evacuation or spasms of the anal muscles that can come and go throughout the day.
| Symptom | Anal Fissure | Hemorrhoids | Perianal Abscess |
|---|---|---|---|
| Pain timing | During and after bowel movement | Usually painless or mild discomfort | Constant, worsening pain |
| Bleeding | Bright red, on paper/stool surface | Bright red, often drips into toilet | Minimal or pus discharge |
| Swelling | Minimal, possible skin tag | Bulging tissue around anus | Tender, warm swelling |
What Causes Anal Fissures?
The most common cause of anal fissures is constipation, where hard, dry stools stretch and tear the anal lining during bowel movements. Other causes include chronic diarrhea, childbirth, inflammatory bowel disease, and conditions that affect blood flow to the anal area. The tear triggers muscle spasm that reduces blood flow, creating a cycle that prevents healing.
Understanding what causes anal fissures helps in both treatment and prevention. The primary mechanism involves mechanical trauma to the anal canal lining, but several factors can contribute to this damage and interfere with the normal healing process.
Constipation: The leading cause
Constipation is responsible for the majority of anal fissures. When stool remains in the colon too long, the body absorbs more water from it, making it hard, dry, and difficult to pass. This hardened stool requires more straining and stretches the anal canal beyond its capacity, causing the lining to tear. The resulting pain then makes people reluctant to have bowel movements, which worsens constipation and creates a self-perpetuating cycle.
Factors that contribute to constipation include inadequate fiber intake, not drinking enough water, sedentary lifestyle, ignoring the urge to defecate, certain medications (including opioids, antidepressants, and iron supplements), and underlying conditions such as irritable bowel syndrome or hypothyroidism. Addressing these underlying factors is essential for preventing recurrence.
Chronic diarrhea
While less common than constipation, chronic diarrhea can also cause anal fissures. Frequent loose stools irritate and erode the anal lining over time. The acidic content of diarrhea can chemically damage the mucosa, and constant wiping further traumatizes the area. People with conditions causing chronic diarrhea, such as inflammatory bowel disease, celiac disease, or infections, may be particularly susceptible.
Childbirth and pregnancy
Anal fissures frequently occur during and after childbirth, particularly vaginal delivery. The intense pressure and stretching during delivery can directly traumatize the anal canal. Additionally, many women experience constipation during pregnancy and the postpartum period due to hormonal changes, iron supplementation, pain medication use, and reluctance to strain after delivery. Women who experience significant perineal tears during delivery are at higher risk for anal fissures.
Other medical conditions
Certain medical conditions increase the risk of developing anal fissures or can cause fissures in atypical locations. Crohn's disease and ulcerative colitis cause inflammation that weakens the anal tissue and impairs healing. Fissures in Crohn's disease may be multiple, deep, and occur off the midline. Sexually transmitted infections including syphilis, herpes, chlamydia, and HIV can cause anal ulcerations that resemble fissures. These typically require specific treatment beyond standard fissure management.
When an anal fissure forms, it triggers increased tension in the internal anal sphincter muscle. This hypertonia (excessive muscle tone) serves as a protective mechanism but ultimately hinders healing. The spasm reduces blood flow to the already damaged tissue, depriving it of the oxygen and nutrients needed for repair. This explains why treatments that relax the sphincter are often more effective than simply treating the wound itself.
What Can I Do at Home to Treat an Anal Fissure?
Home treatment for anal fissures focuses on keeping stools soft, reducing pain, and promoting healing. Key strategies include taking warm sitz baths for 10-20 minutes several times daily, eating a high-fiber diet, drinking plenty of water, using over-the-counter pain-relieving ointments, and not delaying bowel movements despite the pain.
Most acute anal fissures heal with conservative home treatment, and even chronic fissures may improve significantly with diligent self-care. The goals of home treatment are to break the pain-spasm-constipation cycle, promote blood flow to the area, and create conditions favorable for tissue repair.
Sitz baths: Your best friend
Sitz baths are one of the most effective and soothing treatments for anal fissures. A sitz bath involves sitting in warm (not hot) water that covers your hips and buttocks. The warm water helps relax the internal anal sphincter muscle, increases blood flow to the area, and provides significant pain relief. You can use a sitz bath basin that fits over your toilet seat or simply sit in a bathtub with a few inches of warm water.
For best results, take sitz baths for 10-20 minutes, especially after bowel movements when pain is most intense. Many people find relief by taking 2-3 sitz baths daily. Adding Epsom salts is optional and provides no proven additional benefit, though some find it soothing. After the bath, gently pat the area dry rather than rubbing, and avoid using harsh soaps or bubble baths that can irritate the sensitive tissue.
Fiber: The foundation of prevention
Increasing dietary fiber is essential for both treating and preventing anal fissures. Fiber adds bulk to stool and helps it retain water, making it softer and easier to pass. Adults should aim for 25-35 grams of fiber daily, though it's important to increase intake gradually to avoid bloating and gas. Good sources of fiber include fruits (especially berries, apples, and pears with skin), vegetables, whole grains, legumes (beans and lentils), and nuts.
If getting enough fiber from food alone is difficult, fiber supplements can help. Psyllium husk (Metamucil), methylcellulose (Citrucel), and wheat dextrin (Benefiber) are commonly used. Start with a small dose and increase gradually while drinking plenty of water, as fiber supplements can cause constipation if taken without adequate fluids.
Hydration matters
Water works together with fiber to keep stools soft. Aim for at least 8 glasses (about 2 liters) of water daily, and more if you're active or in hot weather. Other fluids count too, but water is best. Caffeinated and alcoholic beverages can be dehydrating, so they shouldn't be your primary fluid sources. A good indicator of adequate hydration is urine that's light yellow to clear in color.
Over-the-counter treatments
Several over-the-counter products can provide relief from anal fissure symptoms. Topical anesthetics containing lidocaine or benzocaine can temporarily numb the area and reduce pain during and after bowel movements. Apply before a bowel movement when possible. Products marketed for hemorrhoids (such as Preparation H) can also help relieve pain and itching, though they don't specifically treat fissures.
Stool softeners like docusate sodium (Colace) can make stools easier to pass without straining. These are particularly useful when starting fiber therapy, as they work more quickly. Over-the-counter osmotic laxatives like polyethylene glycol (MiraLAX) can be used short-term if fiber and fluids aren't providing enough relief. However, stimulant laxatives should generally be avoided as they can cause cramping and urgency.
Don't delay bowel movements
When you feel the urge to have a bowel movement, don't delay or hold it. The longer stool remains in the colon, the more water is absorbed and the harder it becomes. Fear of pain often leads people to postpone bowel movements, but this creates a vicious cycle of worsening constipation. It's better to go when your body signals the need, use the treatments described above for pain management, and allow the fissure to heal gradually.
While most acute fissures heal with conservative treatment, you should see a healthcare provider if pain is severe and over-the-counter treatments don't help, bleeding continues or worsens, symptoms haven't improved after 4-6 weeks of home treatment, you develop fever or signs of infection, or you have a chronic condition like Crohn's disease that may be contributing to the problem.
When Should You See a Doctor for an Anal Fissure?
See a doctor if pain persists despite home treatment, bleeding continues without a known cause, the fissure doesn't heal after 6 weeks, you have severe symptoms affecting daily life, you notice signs of infection (fever, increasing pain, discharge), or you have conditions like inflammatory bowel disease that may be causing the fissure.
While many anal fissures heal with home care, medical evaluation is important in certain situations to ensure proper diagnosis, rule out other conditions, and access more effective treatments when needed.
Reasons to seek medical care
You should contact a healthcare provider if you experience any of the following: significant rectal bleeding, especially if you don't know the cause or if it's more than a small amount; pain in the anal area that isn't relieved by over-the-counter treatments; a fissure that hasn't healed after 6 weeks of consistent home treatment; pain so severe that it interferes with daily activities or causes you to avoid bowel movements; symptoms of infection such as fever, increasing redness, warmth, or pus drainage; or if you have a condition like Crohn's disease, ulcerative colitis, or HIV that may be related to the fissure.
It's also important to see a doctor if this is your first episode of rectal bleeding to confirm the diagnosis, particularly if you're over 40 or have risk factors for colorectal cancer, as some symptoms of fissures overlap with more serious conditions.
What to expect at the doctor's office
Your doctor will ask about your symptoms, bowel habits, and medical history. The physical examination typically includes a visual inspection of the anal area to look for the fissure, which is usually visible at the posterior midline. A gentle digital rectal examination may be performed, though this is often deferred initially if pain is severe. In some cases, an anoscopy (examination with a small viewing instrument) may be needed to better visualize the fissure or rule out other conditions.
For chronic or atypical fissures, additional tests may be recommended. These might include blood tests to check for inflammatory markers or signs of infection, stool tests if inflammatory bowel disease is suspected, or colonoscopy if there's concern about other conditions affecting the colon or rectum.
How Are Anal Fissures Treated Medically?
Medical treatment for anal fissures that don't heal with home care includes prescription ointments (topical nitroglycerin or calcium channel blockers) that relax the sphincter muscle and improve blood flow, botulinum toxin injections to temporarily paralyze the sphincter, and surgery (lateral internal sphincterotomy) which has over 90% success rates for chronic fissures.
When conservative home treatment doesn't result in healing, medical therapies aim to address the underlying sphincter spasm and reduced blood flow that prevent tissue repair. Treatment is typically stepped, starting with less invasive options before considering surgery.
Topical medications: First-line prescription treatment
Topical nitroglycerin (0.2-0.4%) is often the first prescription medication tried for anal fissures. It works by releasing nitric oxide, which relaxes the internal anal sphincter and increases blood flow to the fissure. The ointment is applied to the anal canal 2-3 times daily for 6-8 weeks. Healing rates range from 40-60%. The most common side effect is headache, which affects about 20-30% of users but often improves with continued use or dose adjustment.
Topical calcium channel blockers such as diltiazem (2%) or nifedipine are alternatives to nitroglycerin and may have fewer headache-related side effects. They also relax the sphincter muscle and improve blood flow, with similar healing rates to nitroglycerin. These are particularly useful for patients who can't tolerate nitroglycerin due to headaches or who are taking medications that interact with nitrates.
Botulinum toxin injection
Botulinum toxin (Botox) injection is an option for fissures that don't respond to topical treatments. The injection temporarily paralyzes part of the internal anal sphincter, reducing spasm and allowing the fissure to heal. The effect lasts 2-3 months, usually enough time for healing to occur. Success rates range from 60-80% for chronic fissures.
The procedure is typically done as an outpatient, sometimes under local anesthesia. Side effects may include temporary mild incontinence to gas or liquid stool in about 5-10% of patients, though this usually resolves as the toxin wears off. Multiple injections may be needed in some cases.
PTNS (Percutaneous Tibial Nerve Stimulation)
PTNS is a newer treatment option that uses electrical stimulation to modulate the nerves controlling the pelvic floor and anal sphincter. During treatment, a thin needle is inserted near the ankle, connecting to a device that delivers mild electrical impulses. These impulses travel along the tibial nerve to the nerves that control the anal sphincter, helping to reduce spasm and improve blood flow.
Treatment sessions typically last about 30 minutes, and most patients need 10-12 sessions for optimal results. The treatment is generally well-tolerated, with minimal discomfort. Some patients may experience temporary tingling or numbness in the foot after treatment. While relatively new for anal fissures, PTNS has shown promising results in clinical studies.
Surgical treatment: When other options fail
Lateral internal sphincterotomy (LIS) is the gold standard surgical treatment for chronic anal fissures that don't respond to conservative measures. The surgery involves making a small cut in the internal anal sphincter muscle to permanently reduce its tension. This eliminates the spasm, improves blood flow, and allows the fissure to heal. Success rates exceed 90%, making it the most effective treatment available.
The procedure can be done under local, regional, or general anesthesia, usually as an outpatient surgery. Recovery typically takes 1-2 weeks for return to normal activities, though complete healing may take longer. The main risk of surgery is some degree of fecal incontinence, which occurs in about 5-10% of patients to some extent (usually limited to difficulty controlling gas or minor leakage). Permanent, significant incontinence is rare but possible, which is why surgery is reserved for cases where other treatments have failed.
Fissurectomy and advancement flaps
For complex or recurrent fissures, or when there's concern about incontinence risk, alternative surgical approaches may be considered. Fissurectomy involves removing the fissure and any associated skin tag, allowing fresh tissue to form. Advancement flaps involve moving healthy tissue to cover the fissure site. These procedures may be combined with partial sphincterotomy or botulinum toxin injection.
How Can You Prevent Anal Fissures?
Preventing anal fissures centers on maintaining soft, regular bowel movements through a high-fiber diet (25-35g daily), adequate hydration (8+ glasses of water), regular exercise, and responding promptly to the urge to defecate. Proper anal hygiene and avoiding straining during bowel movements are also important preventive measures.
Once an anal fissure has healed, preventing recurrence is an important ongoing goal. The same measures that help heal fissures also help prevent them from forming in the first place.
Lifestyle modifications for prevention
The cornerstone of prevention is avoiding constipation. Eating a diet rich in fiber from fruits, vegetables, whole grains, and legumes keeps stools soft and easy to pass. Staying well-hydrated helps fiber work effectively. Regular physical activity stimulates bowel function and helps maintain regularity. Establishing regular bowel habits—going at the same time each day when possible—can help prevent constipation.
When you feel the urge to have a bowel movement, don't delay. Holding it in allows more water to be absorbed from the stool, making it harder. Avoid straining or sitting on the toilet for extended periods (reading or phone use can lead to prolonged sitting). The bowel movement should be allowed to happen naturally without forceful pushing.
Proper anal hygiene
Keeping the anal area clean and dry helps maintain healthy tissue. After bowel movements, wipe gently with soft, unscented toilet paper or use moist wipes designed for sensitive skin. Avoid harsh or scented soaps around the anus, as these can cause irritation. Pat dry rather than rubbing. Wearing cotton underwear allows better air circulation than synthetic materials.
Special considerations
People with conditions that predispose to fissures need to be especially vigilant. Those with inflammatory bowel disease should work with their gastroenterologist to keep their condition well-controlled. Pregnant women should be proactive about preventing constipation through diet, hydration, and safe stool softeners if needed. People taking medications that cause constipation (such as opioid pain relievers) should discuss preventive measures with their healthcare provider.
Frequently Asked Questions About Anal Fissures
Most acute anal fissures heal within 4-6 weeks with proper home treatment including warm sitz baths, high-fiber diet, adequate fluid intake, and over-the-counter pain relief. The key is maintaining soft stools and breaking the pain-spasm cycle that prevents healing.
Chronic fissures that persist beyond 6-8 weeks may require additional medical treatment such as prescription ointments (topical nitroglycerin or calcium channel blockers), botulinum toxin injections, or surgery. With appropriate treatment, even chronic fissures can heal, though it may take several months.
Healing time varies depending on the severity of the fissure, underlying causes, overall health, and how consistently treatment is followed. Continuing preventive measures after healing is important to avoid recurrence.
The best initial treatment for most anal fissures is conservative home care: warm sitz baths for 10-20 minutes several times daily (especially after bowel movements), a high-fiber diet with 25-35 grams of fiber daily, drinking at least 8 glasses of water daily, and using over-the-counter pain-relieving ointments before and after bowel movements.
For fissures that don't heal with home treatment, prescription topical medications like nitroglycerin ointment or diltiazem cream can help relax the sphincter muscle and improve blood flow. These heal 40-60% of chronic fissures.
When conservative treatments fail, botulinum toxin injections (60-80% success) or lateral internal sphincterotomy surgery (>90% success) may be recommended. Surgery is the most effective treatment but is typically reserved for chronic fissures due to the small risk of incontinence.
Some acute anal fissures can heal on their own within a few weeks, particularly if the underlying cause (such as a temporary episode of constipation) resolves. However, many fissures don't heal without active treatment because pain triggers a cycle that prevents healing.
When a fissure forms, the pain causes the internal anal sphincter to spasm. This spasm reduces blood flow to the area, depriving the tissue of oxygen and nutrients needed for repair. The fear of pain also leads many people to avoid bowel movements, which worsens constipation and causes further trauma to the fissure.
Active treatment—even simple measures like sitz baths and dietary changes—helps break this cycle by softening stools, relaxing the sphincter, and improving blood flow. Without intervention, an acute fissure may become chronic and more difficult to treat.
Lateral internal sphincterotomy, the standard surgery for chronic anal fissures, involves making a small cut in the internal anal sphincter muscle. The procedure is typically done under local or general anesthesia, so you won't feel pain during the surgery itself. It's usually performed as an outpatient procedure.
Post-operative pain is generally manageable and often less than the chronic pain from the fissure itself. Most people can return to normal activities within 1-2 weeks, though complete healing may take longer. Pain medication, sitz baths, and stool softeners are typically recommended during recovery.
The main risk of surgery is some degree of fecal incontinence, affecting about 5-10% of patients. This usually involves difficulty controlling gas or minor leakage and often improves over time. Permanent, significant incontinence is rare but possible. Success rates for healing exceed 90%, making it the most effective treatment for chronic fissures.
Anal fissures and hemorrhoids are different conditions, though they share some symptoms and risk factors. An anal fissure is a tear in the lining of the anal canal, while hemorrhoids are swollen blood vessels in the rectum or anus (similar to varicose veins).
The key difference is in the pain pattern. Anal fissures cause severe, sharp pain during and after bowel movements, often described as cutting or tearing pain. Hemorrhoids are often painless or cause only mild discomfort, unless they become thrombosed (contain a blood clot).
Both conditions can cause bright red rectal bleeding. With fissures, blood is typically seen on the stool surface or toilet paper. With hemorrhoids, blood may drip into the toilet bowl. Hemorrhoids may cause a visible bulge or protrusion at the anus, while fissures appear as a linear crack. Both conditions are often related to constipation and straining, and may occur together.
Yes, anal fissures are common in infants and children. They are actually one of the most frequent causes of rectal bleeding in children. Fissures in children typically occur during the first year of life or during toilet training when constipation is common.
In children, anal fissures almost always heal with conservative treatment including dietary changes to soften stools, increased fluid intake, and warm baths. Making sure children get enough fiber from fruits, vegetables, and whole grains, along with adequate water, is usually sufficient to resolve the problem and prevent recurrence.
Parents may notice blood on the diaper or toilet paper, or a child may cry or show reluctance to have bowel movements due to pain. If a child develops rectal bleeding, it's worth having it evaluated by a pediatrician to confirm the diagnosis and rule out other causes.
Medical References and Sources
This article is based on current evidence-based medical guidelines and peer-reviewed research:
- Stewart DB, Gaertner W, Glasgow S, et al. Clinical Practice Guideline for the Management of Anal Fissures. American Society of Colon and Rectal Surgeons (ASCRS). Diseases of the Colon & Rectum. 2023.
- Nelson RL, Thomas K, Morgan J, Jones A. Non-surgical therapy for anal fissure. Cochrane Database of Systematic Reviews. 2022.
- World Gastroenterology Organisation (WGO). WGO Practice Guidelines: Constipation - A Global Perspective. 2023.
- Wald A, Bharucha AE, Cosman BC, et al. ACG Clinical Guideline: Management of Benign Anorectal Disorders. American Journal of Gastroenterology. 2021;116(10):1987-2008.
- Perry WB, Dykes SL, Buie WD, et al. Practice parameters for the management of anal fissures. Diseases of the Colon & Rectum. 2023.
- Mapel DW, Schum M, Von Worley A. The epidemiology and treatment of anal fissures in a population-based cohort. BMC Gastroenterology. 2020;14:129.
About Our Medical Editorial Team
This article was written and reviewed by the iMedic Medical Editorial Team, which includes board-certified physicians specializing in gastroenterology and colorectal surgery. Our team follows strict editorial standards based on:
All content is based on Level 1A evidence from systematic reviews, meta-analyses, and clinical practice guidelines from recognized medical organizations.
iMedic has no commercial funding or pharmaceutical sponsorship. Our medical information is independent and focused solely on patient education and welfare.
Learn more about our medical team | Read our editorial standards