Anal Fissures

Anal fissures

Anal fissures (AF), also known as fissure-in-ano, are tears in the tissue that lines the anus and anal canal.  These tears can be extremely irritating, itchy and painful.

For some reason, any condition involving our rectum or anus are usually considered embarrassing.  These embarrassing conditions include hemorrhoids and anal fissures.

Let’s learn about this condition and hopefully we can see that this is a condition that there is no reason to feel embarrassed about.

Anal Fissures General Information

Fissures occur equally in both men and women.  They occur most commonly in middle-aged individuals.  The average age of individuals experiencing fissures is 40 years old.  The age range tends to be 20 to 60 years old but can be seen in younger and older individuals.

It is estimated that around 235,000 new cases of anal fissures develop annually in the U.S.

AF are tears in the skin of the lower anal canal and anus.  The skin of the anal canal is also known as the anal mucosa.  These tears can be linear (i.e. a straight line) or they can be elliptical/oval.

Anal fissures are caused by some form of trauma to the anal skin.  Most commonly, anal fissures are caused by constipation and straining to pass hard stools.  Other causes include chronic diarrhea, anal sex, previous anal surgery, sexually transmitted infections, Chrohn’s disease, ulcerative colitis, HIV, anal cancer, giving birth to a child and tuberculosis.

Dentate Line and Anal Verge

To better understand AF it is important to know some basic terminology.

The anal verge is the transitional point between the end of the anal canal (the skin of the anal canal) and the skin of the perianal area.  Basically, and for lack of a better way of describing it, the anal verge is essentially where you can visually see your anus.

The dentate line, also known as the pectinate line, is found approximately 2 centimeters (almost 1 inch) above the anal verge inside the anal canal.  This line divides the upper 2/3rds of the anal canal from the lower third of the anal canal.

Anal fissures happen below the dentate line. The fissures tend to be between the dentate line and the anal verge but can extend beyond the anal verge into the perianal region.

Where Do Fissures Occur?

Most fissures occur to the posterior or back side of the anal canal.  In fact, around 75% of anal fissures occur on the back part of the anal canal.  Approximately, 25% occur on the anterior or front side of anal canal.  These front-type of anal fissures are more common in women.  The posterior and anterior fissures are known as typical anal fissures.

Another type of fissure, known as an atypical (not usual) fissure, occurs to the sides of the anal canal (i.e. on the sides of the anal canal towards your hips).  Atypical fissures are found in less than 1% of people with anal fissures.  These atypical fissures occur more in certain conditions such as Chrohn’s disease, ulcerative colitis, cancer and HIV.

Anal Fissure

Anal Fissure Symptoms

Most people with anal fissures experience pain and bleeding during bowel movements.  Hemorrhoids can also lead to bleeding during bowel movements but may not be as painful as fissures.  However, hemorrhoids may also be accompanied by some slight pain.

The number one symptom experienced by individuals with fissures is pain.  Approximately 90% of people with fissure-in-ano complain of pain.  The pain is most common during bowel movements and can last for minutes to hours following defecation.  The pain involved is usually described as sharp or tearing.

The second most common symptom reported with fissures is bleeding.  Just over 70% of people report bleeding with AF.  There can be blood streaks on the stool or even blood dripping into the toilet.  However, most people simply notice blood on their toilet paper after wiping.

Increased pressure within the internal anal sphincter creates an environment where the healing of fissures is difficult.  Reducing the pressure in the internal anal sphincter is one of the main goals of AF therapy.  Due to this increase in the pressure exerted by the internal anal sphincter individual’s will complain about a feeling of anal pressure.

Acute vs. Chronic Anal Fissures

Anal fissures can be classified as acute AF or chronic AF.  Acute AF (AAF) is an fissure that has been present for less than 8 weeks.  A fissure becomes classified as a chronic fissure (CAF) once it has been present for 6 to 8 weeks.  With CAF there usually have been structural changes occur in the anal mucosa and also in the underlying structures.

Non-surgical Management of Anal Fissures

To manage this condition treatments range all the way from simple, lifestyle changes and medications (nonsurgical management) to very complicated and invasive surgical interventions.

There are 3 main goals with non-surgical interventions for AF:

  1. find and eliminate the root cause that created the fissure (most commonly constipation)
  2. reducing the pressure/hypertonicity of the internal anal sphincter to better allow blood flow to, and healing of, the fissure
  3. symptom reduction (reduce pain and bleeding)

Constipation or passing of hard stools can lead to the development of fissures.  Constipation, the passing of hard stools and straining tend to cause trauma to the anal mucosa.  This is why the most simple preventative measures and treatments for AF involve methods to soften the stool.

These simple lifestyle changes include drinking lots of water, eating a high fiber diet, using a psyllium fiber supplement and/or taking a stool softener.  By using these lifestyle changes stools can be softened allowing minor fissures to heal.


The absolute simplest place to start in preventing or treating anal fissures is supplementing the diet with psyllium fiber.  Metamucil® is a well known brand of psyllium fiber supplement.  However, psyllium husks, can be found in a powder form or a capsule form at almost any pharmacy or health food store.  Psyllium may sometimes be called ispaghula.

Psyllium comes from the husks of the seeds of Plantago ovata.  It is a soluble fiber that forms a gel-like substance in the intestines.

Psyllium fiber supplementation should be used three times daily.  Using psyllium three times a day has been found to be more effective in helping to heal fissures than simply taking it once a day.

The critical component to remember when using psyllium fiber is to drink a lot of water throughout the day.  Psyllium requires water to be effective.  It absorbs and dissolves in water creating a gel-like substance that softens the stools.  This is very important in helping to heal anal fissures.

Sitz Baths

Sitz Baths

Sitz baths are another proven treatment to help heal anal fissures.

A sitz bath is a warm, shallow bath that is used to soak the anus and perianal area.

Sitz baths provide several benefits that help in the healing of AF.  First, sitz baths help to keep the anus clean.  Second, they have been shown to reduce pain.  Thirdly, they reduce the hypertonicity of the internal anal sphincter.

It is important that the sitz bath be warm enough to produce the relaxing effect on the internal anal sphincter.  One study showed that a sitz bath at 40 degrees Celcius (104 degrees Fahrenheit) provided the optimal decreases in pressure in the anal canal.

Sitz baths should be utilized two to three times a day for 10 to 15 minutes per session.

Several studies have shown that the combination of sitz baths plus increased dietary fiber can heal most cases of acute anal fissures.

Topical Treatments

There are prescription treatments that you can get from your pharmacy.  A prescription from your family physician or proctologist is required to obtain these prescription treatments.

Calcium Channel Blockers

Two calcium channel blockers, nifidipine and diltiazem, have been used to treat fissures.

Topical nifedipine ointment and diltiazem ointment have been used successfully to treat anal fissures.  These medications have been shown to decrease the internal sphincter pressure and allow blood flow to the area.  These actions created by the calcium channel blockers provide improved conditions which allows the fissure to heal.

Topical nifedipine ointment and topical diltiazem are not commercially available.  This means that you will need to find a compounding pharmacy in your area that can make these compounded ointments.


Nitric oxide is a natural, biological neurotransmitter found in the body.  It is believed that nitric oxide can reduce internal anal sphincter pressure and increase blood flow to the fissure.

Glyceryl trinitrate, is a nitrate that was once a hopeful candidate for treating anal fissures due to it’s conversion into nitric oxide.

Glyceryl trinitrate had minimal success in treating AF but has fallen out of favor as a treatment due to intolerable side effects.  It caused significant systemic vasodilation leading to hypotension and severe headaches.

Botox® (Botulinum Toxin)

Botulinum toxin causes temporary muscle paralysis.  When injected into an area the effects last about 3 months.

To treat anal fissures, botulinum toxin is injected into the internal anal sphincter.  This reduces the hypertonicity of the internal anal sphincter which helps in healing the fissure.

One potential side effect of Botox® is fecal incontinence however this is relatively rare.

Surgical Interventions for Anal Fissures

Surgical interventions for anal fissures include:

  • lateral internal sphincterotomy
  • anal dilation
  • advancement flaps
  • fissurectomy

Of these surgical interventions, lateral internal sphincterotomy is the gold standard surgical treatment for anal fissures.  It is the most common and most successful surgical intervention for AF.

Lateral internal sphincterotomy involves cutting a small portion of the internal anal sphincter underlying the fissure.  This allows for relief of the pressure of the internal anal sphincter upon the fissure.

The main side effect of lateral internal sphicterotomy is fecal incontinence.  However, its occurrence is relatively rare following this surgery.

No matter what treatment is used, proper cleaning and care of the rectum and anus is required after each bowel movement.

The use of moist, flushable wipes over toilet paper can be helpful.

To learn more about hemorrhoids, visit our hemorrhoids page.