Anal Fissure

An anal fissure is a small tear in the lining of the anal canal. It is usually caused by passing a hard or large bowel movement, and it produces a sharp pain at the time, often followed by an aching or burning pain that lasts minutes to hours. A small amount of bright red blood on the toilet paper, or on the surface of the stool, is a common part of the picture.

What an anal fissure is, and what it is not

A fissure is a tear. It is not a growth, and it is not a haemorrhoid. Haemorrhoids are swollen blood vessels and tend to cause itching, a lump, or bleeding without much pain. A fissure causes a distinct sharp pain at the moment of a bowel movement. The two are easily confused and are managed differently, which is one reason an examination is worth having rather than working from guesswork.

Fissures are also described by how long they last rather than by how much they hurt. One that heals within six to eight weeks is called acute. One that persists beyond that is called chronic, and it is often being held open by spasm in the muscle underneath, which reduces blood flow to the tear and slows healing. About 90 per cent sit in the midline at the front or the back of the anal opening. A fissure somewhere else prompts a Canadian clinician to look for another cause, such as Crohn disease or an infection.

Signs and symptoms

• Sharp or tearing pain during a bowel movement
• Burning or aching pain that continues for minutes to hours afterward
• Small amounts of bright red blood on the toilet paper or on the surface of the stool
• A visible small tear or split at the anal opening
• Spasm or tightness in the anal muscle
• A small skin tag or lump near the tear in longer standing cases
• Putting off bowel movements to avoid the pain, which tends to make constipation worse

The last of those matters more than it looks. Pain leads to delay, delay leads to harder stools, and harder stools reopen the tear, which is why care usually starts with the bowel rather than the tear itself.

What raises the risk

Some risk factors cannot be changed:

• Crohn disease and other inflammatory bowel conditions
• Childbirth and the weeks shortly after delivery
• Previous anal surgery or scarring
• Higher resting tone in the internal anal sphincter muscle

Others can often be worked on, usually with support from a health care team:

• Constipation and straining to pass hard stools
• Low fibre intake and not drinking enough fluid
• Repeated episodes of diarrhoea, and long periods spent sitting on the toilet

How an anal fissure is diagnosed in Canada

Diagnosis is made from your history and a physical examination rather than from a scan or a blood test. Alberta Health Services states in its provincial pathway for perianal conditions that no assessment is complete without a digital rectal examination, alongside inspection of the skin and an assessment of muscle tone, although the examination is sometimes deferred until pain is better controlled. Colonoscopy or flexible sigmoidoscopy is arranged when there are alarm features, when rectal bleeding is new in an older adult, or when the fissure sits away from the midline, in order to look for inflammatory bowel disease or a growth.

Treatment and day-to-day management

Clinical research for Anal Fissure is enrolling. See the current studies ↓

Care in Canada works on the bowel first, because a tear that keeps being reopened by hard stools has little chance to close. Depending on how long you have had symptoms and what you have already tried, a health care team may discuss:

• Bowel management to keep stools soft, including dietary fibre, enough fluid, and bulking agents such as psyllium
• Sitz baths and simple hygiene measures for comfort, and changes to toileting habits that reduce straining
• Topical prescription treatments applied to the anal area, including calcium channel blockers such as diltiazem or nifedipine, and nitrate preparations
• Botulinum toxin injection into the internal anal sphincter, offered by surgeons for fissures that persist
• Surgery, most often lateral internal sphincterotomy, for chronic fissures that have not settled with conservative and topical care

The Alberta pathway suggests reassessing after about six weeks of conservative care and, if the fissure has not settled, running a second six week trial before a surgical referral is considered. Timelines differ from person to person. These are decisions for you and your own clinician, and nothing on this page is a recommendation about any of them.

When to talk to a doctor

• Rectal bleeding that is heavy, keeps coming back, or is mixed through the stool rather than sitting on its surface, particularly if you are over 50
• Fever, chills, spreading redness, or a painful lump near the anus, which can mean an abscess
• Unintended weight loss, any change in bowel habit that persists, or a fissure that has not healed after several weeks of care, all of which warrant prompt assessment

Why clinical research matters for anal fissure

Most fissures settle with fibre, sitz baths and topical treatment. A minority do not, and the main open question is how to help that group without the small risk of lasting continence problems that comes with cutting the sphincter muscle. Studies are comparing topical agents against one another, testing botulinum toxin technique and placement, evaluating sphincter sparing operations such as fissurectomy with an advancement flap, and looking at combined approaches. Working out in advance who will go on to develop a chronic fissure is also an active question. Trials in this area are smaller and less frequent than in the larger digestive conditions.

Clinical studies are how those questions get answered. Taking part is voluntary, you give informed consent before anything begins, and you can stop at any time without affecting the care you get from your own doctor. A study coordinator will explain the visits, any examinations and the follow up before you decide, and no one can say in advance whether a study will help you personally.

Learn more from Canadian sources

• Alberta Health Services: provincial perianal disease primary care pathway
• Canadian Medical Association Journal: anal fissures
• Canadian Family Physician: topical treatments for anal fissure
• Gastrointestinal Society: constipation