Fissure Treatment: Healing an Anal Fissure

A sharp, tearing pain during bowel movements is the classic sign of an anal fissure — a small tear in the delicate lining of the anal canal. Most fissures heal with simple measures, but persistent ones may need a more targeted treatment or minor surgery.

What Is an Anal Fissure?

An anal fissure is a small tear or cut in the thin, delicate lining of the anal canal. Because this tissue is rich in nerve endings, even a small fissure can cause disproportionately sharp pain — often described as feeling like passing glass — especially during and after a bowel movement. Fissures can be acute (recent, and likely to heal on their own) or chronic (lasting more than six to eight weeks, often with an accompanying skin tag or spasm of the anal muscle).

What Causes an Anal Fissure?

• Passing hard or large stools, usually from constipation — the single most common cause
• Chronic diarrhea, which can also irritate and tear the lining over time
• Childbirth, due to the strain placed on the area
• Reduced blood flow to the area, which can slow healing once a tear forms
• Increased tension (spasm) in the internal anal sphincter, which can both cause and perpetuate a fissure
• Less commonly, an underlying condition such as Crohn's disease

Anal fissures form in the delicate lining of the anal canal

Signs and Symptoms

• Sharp, cutting, or burning pain during and after bowel movements
• Bright red blood on the toilet paper or in the stool
• A visible tear or crack in the skin around the anus
• A small lump or skin tag near the fissure in chronic cases
• Spasm or tightness of the anal muscle, adding to the pain

Treatment Options

• Increasing fiber and fluids to soften stool and reduce straining — often the single most important step
• Sitz baths — warm water soaks several times a day to relax the anal muscle and ease pain
• Topical medications, such as nitroglycerin or calcium channel blocker creams, which relax the internal anal sphincter and improve blood flow to help the fissure heal
• Botox injections into the anal sphincter, used for fissures that don't respond to topical treatment, temporarily relaxing the muscle to allow healing
• Stool softeners to prevent further trauma from hard stools during healing

When Is Surgery Needed?

If a fissure becomes chronic and doesn't heal despite these measures — typically after six weeks or more of appropriate treatment — surgery may be recommended. The most common procedure is a lateral internal sphincterotomy (LIS), in which a small, precise cut is made in part of the internal anal sphincter muscle to reduce its excessive tension. This relieves the spasm that's preventing healing and allows the fissure to close, and it remains the most effective definitive treatment for chronic fissures that haven't responded to non-surgical care.

Recovery

• First few days: Some discomfort at the surgical site is expected, though it's typically far milder than the pain caused by the fissure itself.
• High-fiber diet: Continuing a high-fiber diet and adequate fluids remains essential after treatment to prevent recurrence.
• 1–2 weeks: Most people return to normal activities within this timeframe.

The anal canal is especially sensitive to tearing from hard or large stools

Risks and Considerations

• Minor risk of temporary difficulty controlling gas or stool after sphincterotomy, since it involves the sphincter muscle
• Bleeding or infection
• Recurrence if constipation isn't managed long-term

The Takeaway

Most anal fissures heal within a few weeks with simple dietary changes and topical treatment — surgery is really a backup option for the minority that become chronic. If pain during bowel movements has been going on for more than a couple of weeks, it's worth getting evaluated rather than just pushing through it, since early treatment tends to resolve fissures faster and more comfortably.