Overview

Anus is where the large intestine opens to let the stool (poop) come out. Anus helps in bowel movement, the surrounding nerves and muscles coordinate and when it's time the mucous lining in the anus secretes mucus to lubricate the passage through which the stool is passed.

Anal fissure is a small crack or tear that occurs in the mucus line of the anal canal. Anal fissure occurs due to constipation and straining to pass hard stool. This straining causes anal pain and rectal bleeding. Anal fissure can recur easily even after fully healed, constipation or a hard bowel movement can cause the fissure again.^1,2

Making changes in lifestyle and including high-fibre food in the diet reduces the recurrence of anal fissures.³

Anal fissure

In the anus, the tissue lining inside the large intestine is a soft mucosa which lines the upper portion of the anus and it begins to change from tender mucosa to normal skin. Anus is closed on each side by a ring-like sphincter muscle. When the rectum gets full the nerves trigger the urge to pass the stool, the internal sphincter muscle relaxes automatically but the external sphincter muscle is the one you control to pass the stool when the person is ready. An anal fissure is a small tear in the lining of the anal canal which causes pain and rectal bleeding during passage of the stool (poop). It is caused when a trauma occurs while straining for the stool. An anal fissure can occur to anyone suddenly or gradually, they can heal by themself and in some conditions, they need proper treatment.^1,2

Causes

• Trauma-causing tear in the anal lining
• Chronic diarrhoea
• Anal intercourse
• Prior surgery
• Sexually transmitted infections (STIs): This is a severe infection that develops when viruses, bacteria or parasites infect the body and transmit through bodily fluids during sex⁴
• Passing a large hard stool
• Inflammatory bowel disease (IBD): It is a group of disorders that includes Crohn's disease and ulcerative colitis which affects the digestive system^5,6
• Anal cancer: Anal carcinoma develops in the tissue or lining of the anal canal causing symptoms like rectal bleeding, mass or lump in the area of the anal opening, itching and pain⁷
• Tuberculosis (TB): It is caused by the bacteria Mycobacterium tuberculosis. They spread through the air and commonly affect the lungs but can infect the other parts of the body also⁸
• After vaginal childbirth
• Diaper rash

Symptoms

• Severe pain while passing stool (poop)
• Pain after passing stool lasts up to several hours
• Bright red blood is passed through the stool
• Crack in the skin present around the anus
• A small lump or skin tag near the anal fissure

Diagnosis

Health providers or doctors may ask about medical history, ask about the symptoms present and they may perform a physical examination which includes the inspection of the anal region to confirm anal fissure. Some other tests are : 

• Anoscopy: It is a bedside procedure which helps in examining the inside of the anus, especially the lining of the anus with a special scope called anoscope⁹
• Flexible sigmoidoscopy: In this examination, the lower part of the large intestine is examined. The doctor uses a flexible tube (sigmoidoscope) to insert into the rectum with a camera attached at the end which helps in viewing the inside of the large intestine
• Colonoscopy: Colonoscopy is a type of endoscopy, where it uses a flexible tube with a lighted camera attached at the end. In a colonoscopy, the colonoscope is passed through the anus, rectum and into the colon. This is used to examine the large intestine. During the colonoscopy, the endoscopist can perform certain minor procedures. The common procedures are the removal of polyps, sealing wounds, removing blockage, treating tissues and placing stents. Removal of polyp is sent to test for cancer, this helps in early detection and prevents it from spreading^7,10

Management and treatment

An anal fissure can be healed at home with proper care. Increase intake of fibre and fluids, and sit in warm water for 10 to 20 minutes twice a week, this helps for an easy bowel movement, relax the sphincter muscles and promote healing.²

Non-surgical treatments

• Applying nitroglycerin ointment: This is a vasodilator cream that makes the blood vessel expand helps the blood flow and relaxes the sphincter muscles
• OnabotulinumtoxinA (Botox) injection: This is a muscle relaxant injection which relaxes the anal sphincter muscles and helps in healing 
• Topical anaesthetic cream: These help in reducing the pain
• Calcium channel blockers: Medications such as diltiazem or nifedipine helps the anal sphincter muscles and blood vessels to relax

Surgery

If the anal fissure is not healing with medications or the patient has a chronic anal fissure, which means the anal fissure comes back after healing then the doctors may recommend surgery.³

This procedure is known as internal sphincterotomy and is done under sedation, where the doctor makes a small cut in the anal sphincter muscle to release the tension and promotes healing and reduces spasms and pain.¹¹

Risk factors

• Constipation: Straining for hard stool and passing hard stool can cause a tear in the anal canal and increases the risk
• Age: Anal fissures are more common in infants and adults, but they can occur at any age
• Childbirth: Constipation during pregnancy and straining during childbirth increases the risk for anal fissure after delivery of the baby
• Crohn’s disease: It is an autoimmune disease condition which affects the digestive tract. It is a type of inflammatory bowel disease, which causes abdominal pain, diarrhoea, rectal bleeding and weight loss 
• Anal intercourse: Having sex through the anus can increase the chance of tearing

Recurrence of anal fissure

It is very common for a fully healed fissure to recur after a hard bowel movement or an injury. The steps to reduce the risk of developing fissure are:³

• Follow good hygiene hygiene: Always keep the anal area clean, wash the area with soap and water. Pat dry the area after cleaning. This helps in reducing the infection
• Increase intake of fibre: Increasing intake of fibre and making changes in the diet helps in easy bowel movement. Adding more fruits and vegetables with more water helps the stool to pass easily
• Hydrotherapy: Hydrotherapy involves sitting in hot water for 10 to 20 minutes. This helps in reducing itching and inflammation in the existing fissure. Take hydrotherapy twice a week
• Avoid straining for stool: Staring for stool can increase the risk of anal fissure. To reduce constipation drink plenty of water and have plenty of fibre-rich food
• Avoid excessive wiping: Wiping the anal area excessively after passing the stool can increase the risk of anal fissure. Use soft paper and pat dry after scrubbing
• Avoid constipation medicines: Certain medicines for constipation can increase the risk of anal fissures
• Manage stress: Mental stress can cause muscle tension and interfere with bowel movements. Reduce stress by practising yoga, meditation or any other therapy
• Consult a doctor if symptoms appear: Consult a doctor as soon as possible if the symptoms appear after healing of the anal fissure

FAQ’s

Difference between haemorrhoid and fissure?

Haemorrhoids and fissures both have itching in the anu, and bright red blood is present with the stool or seen in the paper after wiping. The difference is haemorrhoids don’t always have pain but fissures do. The pain of haemorrhoids will be constant while pain in fissure occurs in the episode.

How do you heal an anal fissure? 

Maintaining proper personal hygiene, increasing the intake of fibre and water, avoiding straining for stool and doing hydrotherapy, which involves sitting in warm water for 10 to 20 minutes twice a week. These help in reducing the itching and inflammation of the persistent anal fissure.

Can fissure recur?

A fully healed anal fissure can recur after straining for stool or by another injury. 

What not to do with a fissure?

Straining for stool should be avoided and wiping the anal area too hard can also increase the injury or crack.

Summary

Anus is where the large intestine opens to let the stool (poop) come out. Anus is closed on each side by a ring-like sphincter muscle. When the rectum gets full the nerves trigger the urge to pass the stool, the internal sphincter muscle relaxes automatically but the external sphincter muscle is the one you control to pass the stool when the person is ready. An anal fissure is a small tear in the lining of the anal canal which causes pain and rectal bleeding during passage of the stool (poop). It is caused when a trauma occurs while straining for the stool. An anal fissure can be healed at home with proper care and by increasing intake of fibre and fluids. If the anal fissure is not healing with medications or the patient has a chronic anal fissure, which means the anal fissure comes back after healing then the doctors may recommend surgery. It is very common for a fully healed fissure to recur after a hard bowel movement or an injury.