An anal fissure, or fissure-in-ano, is a crack in the lining of the lower anal canal and can be one of several possible causes for anal pain. The lower anal canal is an extremely sensitive area of skin and can produce fairly significant signals of pain if it is damaged.

Fissures begin as a small tear or ulceration, due to either a bout of diarrhea or sometimes a particularly large bowel movement. Often, the anus is already chronically irritated by something else. The majority of fissures resolve rather quickly and rarely cause any prolonged problem.

Symptoms are sharp pain and a small amount of bright blood during a bowel movement

The symptoms of fissure are sharp, knife-like pain in the anus during a bowel movement, and often the presence of a small amount of bright red blood streaking the toilet paper during wiping. Fissures rarely bleed more than a small amount.

Sometimes, if a fissure becomes chronic (long-standing) and deep, another kind of pain can develop. It is a dull ache in the anus and pelvis that starts a few minutes after the bowel movement and can persist for an hour or two before gradually subsiding. This chronic fissure pain is due to spasm of the internal sphincter muscle (one of the small muscles in the anus) and can be quite debilitating. It is like a recurring "Charley horse" of the anus and can be so bad that patients can no longer work.

Most patients with a fissure-in-ano have pain only with bowel movements and some minor streaking of blood. Once the bowel movement is over, they are fine after a few minutes. It is important to note that the bleeding associated with a fissure-in-ano is bright red and associated with some pain or tenderness in the anus. Dark bleeding of greater amounts without any anal tenderness or pain should be checked by a physician.

Treatment is simple - most of the time a fissure will disappear on its own

The treatment of fissure-in-ano is generally fairly simple. In the vast majority of cases it will go away without any treatment at all. If the fissure doesn't disappear on its own, a change in dietary and hygiene habits can reduce any general irritation to the anal canal that can be the underlying cause of the fissure.

Doing the following can ease irritation of the anal canal:

  • Sitz baths – sit in a tub of warm water (about 46°C) 3 to 4 times a day for 15 minutes each time.
  • Do not put any creams or ointments, corn starch, talcum or other powder, witch hazel, or anything else on or into the anus.
  • Stay hydrated by drinking plenty of fluids and avoiding coffee and alcohol.
  • Do not ignore the urge to use the washroom as stool dries out when it stays in the colon longer and becomes harder to pass.
  • Increase the amount of fibre in your diet by eating vegetables, fruits, whole grains, seeds, and nuts.
  • Sometimes a granulated type of stool fibre bulking agent such as Metamucil (just one teaspoon per day) can help by making the stool a little bulkier. Loose stools are associated with higher rectal pressures, which can delay healing.

Chronic fissure pain can be treated with a simple surgical procedure

When fissures are so chronic and deep (this usually takes several weeks or months) that they cause the dull aching pelvic pain long after a bowel movement, more aggressive treatment may be needed. Currently, the best treatment for this type of condition is a small surgical procedure called a lateral internal sphincterotomy (LIS). In an LIS, the surgeon actually divides the internal sphincter muscle, which reduces the pressure in the anal canal and prevents that muscle from going into spasm.

Usually, the fissure heals within a couple of days, even though the surgeon does nothing to the fissure itself. The operation is based upon the interesting research finding that patients with chronic fissures tend to have excessive anal canal pressure (tightness) and that by reducing the pressure a bit, the fissure can heal. Nowadays, research shows that this is very effective and has minimal risks. It is quite an amazing little operation, and for those who have had serious pain after each bowel movement - sometimes for months or years - it can be a godsend.

Lateral internal sphincterotomy can often be done under local anaesthetic; however, in some cases it is best done in the hospital under general or spinal anaesthetic.The choice depends upon the particular anatomy of the patient and the patient's and surgeon's attitude and experience. The much more substantial external sphincter muscle is left alone during the procedure, and there are minor or short-lived changes to anal control after the LIS surgery.

For most patients with a fissure-in-ano, an operation will never be required. Simple conservative measures, such as the recommended changes in diet and hygiene, will be enough to get rid of the problem.

Michael E. Pezim, MD 
with updates by the MediResource Clinical Team