Overview

An anal fissure is a small tear in the thin, moist tissue (mucosa) that lines the anus. An anal fissure may occur when you pass hard or large stools during a bowel movement. Anal fissures typically cause pain and bleeding with bowel movements. You also may experience spasms in the ring of muscle at the end of your anus (anal sphincter).

Anal fissures are very common in young infants but can affect people of any age. Most anal fissures get better with simple treatments, such as increased fiber intake or sitz baths. Some people with anal fissures may need medication or, occasionally, surgery.

Symptoms

Signs and symptoms of an anal fissure include:

Pain, sometimes severe, during bowel movements
Pain after bowel movements that can last up to several hours
Bright red blood on the stool or toilet paper after a bowel movement
A visible crack in the skin around the anus
A small lump or skin tag on the skin near the anal fissure

Surgery

If you have a chronic anal fissure that is resistant to other treatments, or if your symptoms are severe, your doctor may recommend surgery. Doctors usually perform a procedure called lateral internal sphincterotomy (LIS), which involves cutting a small portion of the anal sphincter muscle to reduce spasm and pain, and promote healing.

Studies have found that for chronic fissure, surgery is much more effective than any medical treatment. However, surgery has a small risk of causing incontinence.

If your symptoms persist, you'll likely need further treatment.

Causes

Common causes of anal fissure include:

Passing large or hard stools
Constipation and straining during bowel movements
Chronic diarrhea
Anal intercourse
Childbirth

Less common causes of anal fissures include:

Crohn's disease or another inflammatory bowel disease
Anal cancer
HIV
Tuberculosis
Syphilis

Treatment

Anal fissures often heal within a few weeks if you take steps to keep your stool soft, such as increasing your intake of fiber and fluids. Soaking in warm water for 10 to 20 minutes several times a day, especially after bowel movements, can help relax the sphincter and promote healing.

Nonsurgical treatments

Your doctor may recommend:

Externally applied nitroglycerin (Rectiv), to help increase blood flow to the fissure and promote healing and to help relax the anal sphincter. Nitroglycerin is generally considered the medical treatment of choice when other conservative measures fail. Side effects may include headache, which can be severe.

Topical anesthetic creams such as lidocaine hydrochloride (Xylocaine) may be helpful for pain relief.

Botulinum toxin type A (Botox) injection, to paralyze the anal sphincter muscle and relax spasms.

Blood pressure medications, such as oral nifedipine (Procardia) or diltiazem (Cardizem) can help relax the anal sphincter. These medications may be taken by mouth or applied externally and may be used when nitroglycerin is not effective or causes significant side effects.