What is an anal fissure?

An anal fissure is a tear in the tissue of the anus. The anus is the last part of the digestive tract. It’s at the end of the rectum. It has a ring of muscle (sphincter) that opens during a bowel movement to allow stool (feces) to pass through. A fissure is caused by the anal tissue stretching too much. This can happen during a hard bowel movement. It causes pain and bleeding.

Anal fissures are not the same as hemorrhoids. But the symptoms can be similar. Hemorrhoids are inflamed blood vessels in or just outside the anus. An anal fissure is one of the most common noncancer (benign) conditions of the anus and rectum.

What causes an anal fissure?

The most common cause is large or hard stools because of constipation. A fissure may also be caused by severe diarrhea, anal sex, vaginal childbirth, or an object inserted into the anus.

Who is at risk for an anal fissure? 

A person is more at risk for an anal fissure if they have any of the below:

• Constipation that makes you strain to pass hard stool

• A low-fiber diet

• A lot of diarrhea

• Recent weight loss surgery, if it leads to frequent diarrhea

• Vaginal childbirth

• Minor injury, such as from mountain biking

• Any inflammatory condition of the anal area

• Inflammatory bowel disease

• Infection or HIV

• Surgery

• Other medical treatments that affect bowel movements or the anus

What are the symptoms of an anal fissure?

An anal fissure is one of the most common causes of anal pain and bleeding. Symptoms can occur a bit differently in each person. They can include:

• Pain during and after a bowel movement that can last for hours

• Visible tear or cut in the area

• Bright red bleeding during or after a bowel movement

The symptoms of an anal fissure may be like other health conditions. See your healthcare provider for a diagnosis.

How is an anal fissure diagnosed?

Your healthcare provider will ask about your symptoms and health history. Your provider will give you a physical exam. The physical exam will include examining your anal area.

Your provider will gently separate your buttocks. The provider will look at the area around the anus for a tear and other signs of a fissure. Where the fissure is may help find the cause. Fissures most often occur in the back center of the anus. Some occur in the front center of the anus. Fissures that occur on the sides of the anus may be caused by conditions such as Crohn’s disease. You may also have:

• Digital rectal exam. The healthcare provider puts a gloved, lubricated finger gently into your anus. A tool called a speculum may also be used. It's put into the anus and gently expanded. This allows the provider to see more of the anal area.

• Fecal occult blood test. This test checks for hidden blood in your stool.

If more tests are needed, your healthcare provider may do a colonoscopy or sigmoidoscopy.

How is an anal fissure treated?

Treatment will depend on your symptoms, your age, and your general health. It will also depend on how severe the condition is.

An acute anal fissure is one that lasts for a short time. It often heals within 6 weeks with simple treatment. It may heal when constipation is treated.

A chronic anal fissure lasts for 6 weeks or more. This may need more treatment, such as surgery.

If your anal fissure doesn’t heal well, you may have a problem with anal pressure because of the sphincter muscle. This prevents blood from flowing normally through the blood vessels in the anus. The reduced blood flow prevents healing. Treatment may include medicine to put on the fissure and botulinum toxin shots (injections). These can help with blood flow and may help an anal fissure heal.

Other treatments include:

• Changes in your diet. You may need to eat more fiber and drink more water to help ease diarrhea or constipation. It’s very important to treat constipation, or the fissure is likely to come back. Ask to see a registered dietitian if you aren't clear on what changes you need to make to your diet. Getting enough fiber will help prevent constipation and large or hard bowel movements.

• Sitz baths. Sitting in a warm, shallow bath for up to 20 minutes a day can help ease symptoms.

• Stool softeners. Medicines to soften stool or fiber supplements may help ease constipation.

• Other medicines. Cream, ointment, or suppository medicines, such as nitrates or calcium blockers may help heal the fissure.

• Surgery. The surgery is called lateral internal sphincterotomy. During the surgery, a small cut (incision) in the muscle helps release the pressure inside the anus. This lets more blood flow through the area to heal tissues.

Talk with your healthcare providers about the risks, benefits, and possible side effects of all treatments.

What are possible complications of an anal fissure?

Pain from the fissure can cause muscle spasm in the anal sphincter muscle. This can make it hard for the fissure to heal. The spasm can also cause more tearing when you have bowel movements. This cycle can lead to a chronic anal fissure in many people.

Other complications can include:

• Ongoing pain and discomfort

• Trouble having bowel movements

• Not having bowel movements because of the pain

• Reduced quality of life

• The fissure coming back after treatment

• Pus-filled infection (abscess)

• Uncontrolled bowel movements and gas

How to manage an anal fissure

If you have an anal fissure:

• Take all medicines as prescribed.

• Don’t eat spicy foods until the fissure heals. Spicy foods may make symptoms worse.

• Maintain a routine bowel habit. Ask your healthcare provider what this should be for you.

To help prevent constipation or large or hard bowel movements:

• Get enough fiber in your diet.

• Drink enough water to stay well hydrated.

When should I call my healthcare provider?

Call your healthcare provider if:

• You see blood in your stool

• Your bowel movements are so painful that you try not to use the bathroom

Key points about anal fissure

• An anal fissure is a tear in the tissue of your anus. This can happen during a hard bowel movement. It causes pain and bleeding. A fissure may also be caused by severe diarrhea or an object inserted into the anus.

• You may have a digital rectal exam and a fecal occult blood test.

• An acute anal fissure often heals within 6 weeks with simple treatment.

• A chronic anal fissure lasts for 6 weeks or more. This may need more treatment, such as surgery.

• Other treatments include stopping constipation with changes in your diet and stool softeners.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.

• Before your visit, write down questions you want answered.

• Bring someone with you to help you ask questions and remember what your provider tells you.

• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

• Ask if your condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if you do not take the medicine or have the test or procedure.

• If you have a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your provider if you have questions.