Definition

An anal fissure is a cut or tear in the lining of the anus. The anus is the opening through which stool leaves the body. Tears generally occur just inside the opening.

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Causes

The exact cause of an anal fissure is unknown. In most cases, tearing is the result of trauma to the anal lining. Trauma can be caused by:

• A large, dry, or hard stool
• Frequent diarrhea
• Tightened anal sphincter, a group of muscles that open and close the anus
• Childbirth
• Anal irritation

Risk Factors

Factors that may increase your chances an anal fissure:

• Constipation
• Straining to pass a bowel movement
• Prior anal surgery, which can cause scarring and decrease the tissue's elasticity
• Chronic diarrhea
• Anoreceptive intercourse
• Crohn disease or ulcerative colitis

Symptoms

An anal fissure may cause:

• Pain during and after a bowel movement
• Burning sensation during a bowel movement
• Bleeding with bowel movements that result in bright red blood either on the toilet tissue or in the bowl
• Small amounts of mucous may be present

Apprehension about bowel movement pain may cause you to delay bowel movements. This can make the symptom worse.

Diagnosis

The doctor will ask about your symptoms and medical history. A physical exam will be done. Anal fissures are generally visible, so diagnosis can be made with an anal exam. If it is not visible, but suspected, your doctor may need to do other tests as long as it is not too painful. These tests include:

• Digital rectal exam—to feel for any lumps or abnormalities
• Anoscopy—examination of the anal canal with a scope
• MRI scan or CT scan if:
  • The fissure not visible on exam
  • The diagnosis is unclear
  • There is significant bright red bleeding in someone with an increased risk for colon or rectal cancer
  • There are features suggesting a secondary anal fissure

Fissures usually occur in predictable locations around the anus. If there are multiple cuts, or a cut in an unusual location, the doctor may order additional tests to look for other conditions.

Treatment

Treatment aims to heal the cut and prevent future anal problems. Most fissures heal on their own or with self-care. Fissures that are fairly new are easier to heal than ones that have persisted for longer than 3 months.

Treatments include:

Prevention

To help reduce your chances of an anal fissure:

• Drink plenty of fluids throughout the day
• Exercise regularly
• Eat foods high in fiber, such as fruits, vegetables, legumes, and whole grains
• Avoid straining during bowel movements
• Follow your treatment plan if you have Crohn disease or ulcerative colitis