Anal Fissures
Overview
What is an anal fissure?
An anal fissure is a small crack or tear in the delicate skin around the anus that causes sharp pain and bleeding during and after a bowel movement. Some fissures are deep enough to expose the muscle tissue under the skin.
The pain of the fissure can trigger spasms in the anal sphincter (ring of muscle controlling passage of feces and gas). This can complicate healing, especially when people try to avoid the pain by repressing the need to have a bowel movement, which can lead to chronic constipation.
The most common causes of anal fissures are constipation accompanied by the passage of a hard stool, persistent diarrhea, or injury due to penetration. Less frequent causes include inflammatory bowel disease (IBD); infections, including HIV infection; and anal cancer.
Acute anal fissures – those lasting less than six weeks – usually heal on their own with self-care. Chronic anal fissures – those lasting longer than six weeks – may involve a deeper tear in the skin and require treatment with medication and sometimes surgery.
Our approach to anal fissures
Patients can often treat their anal fissures with simple measures, such as taking warm baths and adding more fiber to their diet. If the problem keeps recurring or lasts more than six weeks, our gastroenterology experts will determine the most effective treatment based on the medical history and individual needs.
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Symptoms of anal fissures
Anal fissures can occur at any age but most often affect infants and middle-aged adults. Symptoms include:
- Sharp pain that starts during a bowel movement and may last as long as a few hours because of muscle spasms in the anal sphincter
- Bright red blood on the stool or on toilet paper used after a bowel movement
- A small lump or skin tag near the fissure, especially if the problem is chronic
Diagnosis of anal fissures
Your doctor will ask about your symptoms and examine the anal area. An exam is usually sufficient to diagnose the problem. If your doctor thinks it's caused by an underlying condition, such as IBD, you may undergo tests, such as a sigmoidoscopy (exam of the lower part of the colon) or colonoscopy (exam of the entire colon).
Treatment of anal fissures
The goal of treatment is to alleviate pain and control spasms so that the tear in the skin can heal. The choice of treatment depends on whether the fissure is acute or chronic.
Treatment for acute anal fissures
Most acute anal fissures will heal on their own within four to six weeks. You can help the process along with the following self-care measures:
- Take a warm bath, without soap, two or three times a day, especially after bowel movements. The warm water soothes the area and relaxes the anal sphincter muscles. (You can consciously relax those muscles yourself. If you're not sure how, try this while in the tub: Contract the muscle you use to stop having a bowel movement or to stop urinating. Then concentrate on relaxing that muscle. Do this every few minutes while in the tub.)
- Boost the fiber in your diet to soften your bowel movements, which will help the fissure heal. (A hard bowel movement during the healing period can crack the skin open again.) Increase your fiber by eating more raw fruits and vegetables, nuts and legumes (such as beans) and by taking a fiber supplement.
- Drink lots of water, which helps prevent hard stools.
- Take an over-the-counter stool softener.
Treatment for chronic anal fissures
When a fissure is chronic, the first line of treatment is usually one of the following topical medications:
- Lidocaine. While it won't help heal the fissure, lidocaine can relieve the pain by numbing the area.
- Nitroglycerine. This is also called nitrate ointment. Applied around the anal sphincter, it will improve blood flow to the area, which speeds healing.
- Calcium channel blockers. The pills are typically used for high blood pressure, but in topical form, these medications aid fissure healing by relaxing the anal sphincter.
If your fissure persists or your symptoms are severe, your doctor may suggest one of two procedures to relax the muscles in the anal sphincter. Both are highly effective. The options are:
- Botox shot. This injection of botulinum toxin to the anal sphincter paralyzes the muscle, reducing spasms and pain. This allows the fissure to heal.
- Lateral internal sphincterotomy. A surgeon makes a small cut in the sphincter muscle. This lessens the spasming and improves blood flow to the area, so the fissure can heal.
Both treatments are done on an outpatient basis (no hospital stay required).
You and your doctor can discuss the risks of each and determine your best option.
UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.
