Having discomfort during a bowel movement is something many people would recognize but probably not be concerned with. Mild pain or irritation is often associated with constipation, hemorrhoids, or other temporary problems that are likely to resolve on their own. Sometimes, however, the pain becomes progressively more severe instead of improving. This can lead to avoiding bowel movements, changing eating habits, or straining differently in an attempt to reduce discomfort. One possible explanation for this pattern of pain is an anal fissure.

What Is an Anal Fissure?

One of the main reasons pain in this area can be so disruptive is that the lining of the anal canal is made up of highly sensitive tissue. As stool passes through during a bowel movement, the surrounding tissue is exposed to significant physical stress. Having even a small injury or minor irritation in this tissue can produce substantial pain, and that pain is often exacerbated during episodes of constipation or straining. Anal fissures are small tears in the lining of the anal canal that can develop under these conditions.

Anal fissures most often develop after the passage of a hard or unusually large stool that stretches the tissue beyond its normal limits. Chronic constipation is one of the most common contributing factors, since repeated straining places the anal canal under the kind of pressure that makes these tears more likely. Persistent diarrhea can also be a cause, as frequent bowel movements irritate and gradually wear down the lining over time. Childbirth is another recognized risk factor, particularly during vaginal delivery, where the pressure and stretching involved can cause tears in the surrounding tissue.

Once a fissure develops, the body’s response to the injury can actually work against the healing process. The muscles surrounding the anal canal tend to tighten in response to pain, and that tightening places additional pressure on the tear itself. The increased muscle tension also compresses the small blood vessels that supply the area, reducing the flow of oxygen and nutrients that the tissue needs to repair. This creates a cycle where the fissure causes pain, the pain triggers spasm, the spasm restricts blood flow, and the restricted blood flow prevents the fissure from closing. For many patients, this is the reason a fissure that started as a minor tear becomes a persistent problem rather than healing on its own within a few weeks.1

Recognizing the Symptoms of an Anal Fissure

Because anal fissures repeatedly reopen and irritate the surrounding tissue, the symptoms often follow a very recognizable pattern. The most common symptom is a sharp, tearing pain during a bowel movement that may continue long afterward. For many patients, the initial pain transitions into burning, throbbing, or muscle spasms that can persist for minutes or even several hours after using the bathroom. This lingering pain is part of what distinguishes fissures from more temporary forms of irritation.

Bleeding is also common and usually appears as bright red streaks on toilet paper or small amounts of blood in the toilet bowl. Many patients initially assume these symptoms are caused by hemorrhoids, since both conditions can produce pain, irritation, and bleeding. However, fissures are more likely to cause intense pain during and after bowel movements, while internal hemorrhoids often produce bleeding with much less discomfort. A clinical evaluation is often needed to distinguish between the two conditions and determine the most appropriate treatment approach.

Over time, the pain associated with anal fissures can begin to affect normal bowel habits. Patients may start avoiding bowel movements, eating less, or ignoring the urge to go in an attempt to prevent additional pain. These adjustments often lead to harder stools and increased straining, which places additional stress on the injured tissue and increases the likelihood that the fissure will reopen again. In some cases, it is this cycle of pain and disruption to daily routines that ultimately leads patients to seek medical treatment.

Treatment for Acute and Chronic Anal Fissures

Anal fissures are typically diagnosed through a visual examination of the anal area. In most cases, the tear is visible without the need for invasive testing, and a patient’s description of symptoms is often enough to confirm the diagnosis. What usually determines the treatment approach is whether the fissure is acute or chronic. Acute fissures are generally those that have been present for less than six to eight weeks and often respond well to conservative treatment. Chronic fissures persist beyond that point and may develop hardened edges or small external skin tags, making them less likely to heal without more targeted medical intervention.

For acute fissures, treatment focuses on breaking the cycle of hard stools and repeated trauma to allow the tissue to heal on its own. This usually involves increasing dietary fiber, staying well hydrated, using stool softeners to reduce straining, and taking warm sitz baths to relax the surrounding muscles and improve blood flow to the area. These conservative measures resolve the majority of acute fissures without the need for further treatment.

When a fissure becomes chronic and does not respond to conservative management, treatment options typically escalate based on symptom severity and response to earlier therapies:

  • Topical medications: Prescription ointments containing calcium channel blockers or nitroglycerin are applied to the area to relax the sphincter muscle and improve blood flow. Calcium channel blockers are often preferred because nitroglycerin commonly causes headaches that some patients find difficult to tolerate.
  • Botulinum toxin injections: When topical treatments are not effective, Botox can be injected directly into the sphincter muscle to temporarily reduce muscle tension. This creates a period of reduced pressure that allows the fissure time to heal. The procedure carries a small risk of temporary mild incontinence that usually resolves as the medication wears off.
  • Lateral internal sphincterotomy: For fissures that continue to recur despite other treatments, surgery to partially divide the internal sphincter muscle is considered the most effective option. The procedure directly addresses the excessive muscle tension that interferes with healing and has a very high success rate, though it also carries a small risk of long-term changes in bowel control.2

Contact a Gastroenterologist for Relief

Ultimately anal fissures are highly treatable, but persistent or recurring symptoms benefit from a professional evaluation to determine the right approach. The gastroenterology team at Cary Gastro can assess whether a fissure is acute or chronic, identify any underlying contributing factors, and recommend a treatment plan suited to the severity of the condition. If you are experiencing ongoing pain or bleeding during bowel movements, contact our office to request an appointment.




1https://www.ncbi.nlm.nih.gov/books/NBK526063/
2https://www.aafp.org/afp/2024/0200/practice-guidelines-anal-fissures