Overview

An anal fissure is a small tear in the thin, moist tissue that lines the anus. The anus is the muscular opening at the end of the digestive tract where stool exits the body. Common causes of an anal fissure include constipation and straining or passing 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, called the 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 soaking in a warm-water bath. Some people with anal fissures may need medicine or, occasionally, surgery.

Symptoms

Symptoms of an anal fissure include:

  • Pain 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.

When to see a doctor

See your health care provider if you have pain during bowel movements or notice blood on stools or toilet paper after a bowel movement.

Causes

Common causes of anal fissures include:

  • Passing large or hard stools.
  • Constipation and straining during bowel movements.
  • Long-lasting diarrhea.
  • Anal intercourse.
  • Childbirth.

Less common causes of anal fissures include:

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

Risk factors

Factors that may increase your risk of developing an anal fissure include:

  • Constipation. Straining during bowel movements and passing hard stools increase the risk of tearing.
  • Childbirth. Anal fissures are more common in women after they give birth.
  • Crohn's disease. This inflammatory bowel disease causes chronic inflammation of the intestinal tract. This may make the lining of the anal canal more vulnerable to tearing.
  • Anal intercourse.
  • Age. Anal fissures can occur at any age, but are more common in infants and middle-aged adults.

Complications

Complications of an anal fissure may include:

  • Failure to heal. An anal fissure that fails to heal within eight weeks is considered chronic and may need further treatment.
  • Recurrence. Once you've experienced an anal fissure, you are prone to having another one.
  • A tear that extends to surrounding muscles. An anal fissure may extend into the ring of muscle that holds your anus closed. This muscle is called the internal anal sphincter. If this happens, it makes it more difficult for your anal fissure to heal. An unhealed fissure may trigger a cycle of discomfort that may require medicines or surgery to reduce the pain and to repair or remove the fissure.

Prevention

You may be able to prevent an anal fissure by taking measures to prevent constipation or diarrhea. Eat high-fiber foods, drink fluids, and exercise regularly to keep from having to strain during bowel movements.

By Mayo Clinic Staff