What is an Anal Fissure

Reviewed by: HU Medical Review Board | Last Reviewed: January 2018.

Inflammatory bowel diseases like Crohn's disease and ulcerative colitis can cause complications to the tissue around the anus, like anal fissures.1 An anal fissure is a split or tear at the end of the anal canal.2 An anal fissure can be acute or chronic. A fissure that you have had for less than 3 months is acute. A fissure that has been there for 3 months or more is chronic. Chronic fissures may feel hard. You might notice a skin tag or polyp with a chronic fissure.3

There are several causes of anal fissures besides inflammatory bowel disease (IBD). Most anal fissures are centered, that is, they develop on the imaginary line that separates your body into right and left halves. However, anal fissures that are off-center are a sign of Crohn’s disease or ulcerative colitis.2,3

What are symptoms of an anal fissure?

Pain is a symptom of an anal fissure. Many people describe the pain during a bowel movement as if they were “passing shards of glass.”3 Another symptom is bright red blood in the stool.

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However, not all fissures cause pain. Estimates are that 44% to 85% of people with a fissure report pain.4

What other conditions can cause a tear?

Constipation or diarrhea can cause an anal fissure.2 Other less common causes of anal fissures include human immunodeficiency virus (HIV), leukemia, tuberculosis (TB), and anal cancer.2 Trauma during childbirth can injure the anal canal and also cause a fissure.

An anal fissure is diagnosed based on your symptoms and an examination.4 Your health care provider may want to do a rectal examination while you are under anesthesia. This examination is done to be sure that you do not also have an abscess.4

What is the treatment?

About 80% of anal fissures heal on their own.4 Your health care provider may recommend some home treatments to relieve pain and reduce straining during a bowel movement. You may be able to use a topical pain medication to numb the area. You also can try a sitz bath for pain relief. A sitz bath is a shallow bath of warm water for soaking your buttocks.2 Taking a fiber supplement and plenty of water can relieve constipation and reduce straining.4

If the fissure does not heal on its own, medical or surgical treatment may be necessary. The goal of these treatments is to relax the internal sphincter.3 The internal sphincter is a muscle that allows you to control bowel movements. Relaxing this muscle will decrease pain related to the fissure. It allows the fissure to heal on its own.2

Your provider can prescribe medications that help to relax the muscles around the anus. Commonly used medications are nitroglycerine or calcium channel blocker creams or ointments. You apply these directly to the fissure.2,4

If topical medications do not work, another option is a Botox (botulinum toxin) injection. This treatment helps 50% to 80% of patients.2

Finally, a minor surgical procedure can help with healing. This procedure is called sphincterotomy. The surgeon makes a small cut in the internal sphincter. The cut relieves some of the tension and allows the fissure to heal. Sphincterotomy is successful in 90% of people.2 There is a small risk that you could have trouble controlling your bowel movements after this procedure.

What are complications of anal fissures?

There is a risk that you could have another fistula in the future. An unhealed fissure could cause an abscess or fistula to form.5