What is an anal fissure?

An anal fissure is a tear in the lining of the lower rectum (anus) that causes pain during bowel movements. It is a common condition. Anal fissures do not lead to more serious conditions.

Most anal fissures heal with home treatment after a few days or weeks (acute anal fissures). If you have an anal fissure that has not healed after 6 weeks, it is considered a long-term problem (chronic). You may need to take medicine to help a chronic anal fissure heal. Surgery may be necessary for fissures that do not heal with medicine.

Anal fissures affect people of all ages, particularly young and otherwise healthy people. They are equally common in men and women.

Sometimes an anal fissure and a hemorrhoid develop at the same time.

What causes an anal fissure?

Anal fissures are caused by injury (trauma) to the anal canal. Injury can happen if:

• You pass a large stool that stretches the anal canal.
• You are constipated and try to pass a hard stool.
• You have repeated diarrhea.

Childbirth can also cause trauma to the anal canal. During childbirth, some women develop anal fissures. Fissures can also be caused by digital insertion (as during an examination), foreign body insertion, or anal intercourse.

Because many people get constipated or have diarrhea without getting anal fissures, many experts believe there is some other cause of anal fissures. Some people may have excessive tension in the two muscular rings (sphincters) controlling the anus. The external anal sphincter is under your conscious control. But the internal anal sphincter is not under your control. This muscle remains under pressure, or tension, all of the time. A fissure may develop if the internal sphincter's resting pressure becomes too high, causing spasm and reducing blood flow to the anus. This high resting pressure can also keep a fissure from healing.

In some cases, an anal fissure may be caused by Crohn's disease, an inflammatory bowel disease (IBD) that causes bloody diarrhea, abdominal (belly) pain, fever, weight loss, and fissures or fistulas near the anus.

What are the symptoms?

An anal fissure causes a sharp, stinging, or burning pain during a bowel movement. The pain, which can be severe, may last for a few hours.

Fissures may itch. They often bleed lightly or cause a yellowish discharge. You may see a small spot of bright red blood on toilet tissue or a few drops in the toilet bowl. The blood is separate from the stool. Very dark, tarry stools or dark red blood mixed with stool indicates some other condition, possibly inflammatory bowel disease (IBD) or colon cancer. You should contact a doctor if you have any bleeding with bowel movements.