Anal Fistula: Symptoms, Causes, Risk Factors, Treatment

Medically reviewed by Dr. Ramesh Gaddam, M.D. — Written by Sumalatha, D.N.H.E

An anal fistula is an abnormal passageway that develops from inside the anus to the skin outside. Typically, it arises in the upper part of the anus, where the anal glands are located. The condition occurs when one of these glands becomes infected and forms an abscess, leading to drainage that creates the fistula. It’s also sometimes referred to as a perianal fistula, with “perianal” indicating the region around the anus.

 

Prevalence and Symptoms

Anal fistulas are relatively common in the realm of anorectal conditions. They occur twice as frequently in males and individuals assigned male at birth. Around 50% of people who experience an infected anal gland will go on to develop a fistula. These fistulas present with various symptoms, including:

 

  • Anal pain, often intense and throbbing, especially during bowel movements, coughing, or sitting.
  • Swelling and redness (inflammation) inside or around the anus, indicating active infection.
  • Fluid drainage from the area around the anus, which may include pus, blood, or feces, and can be accompanied by an unpleasant smell.
  • Less common symptoms include fever, pain during urination, difficulty holding bowel movements, and occasionally, visibility of the fistula as a hole near the anus.

 

Causes of Anal Fistula

The primary cause of an anal fistula is an anal abscess, which usually develops from an infected anal gland. When an abscess forms at the site of an infection, the pus needs to drain away, which may create a channel leading from the abscess to the outside of the skin, resulting in the fistula.

However, anal fistulas can also have less common causes, including: 

  • Inflammatory bowel diseases, such as Crohn’s disease.
  • Anal sexually transmitted infections (STIs).
  • Tuberculosis affecting the anus.
  • Traumatic injuries or previous surgeries in the anus.
  • Radiation therapy for pelvic region cancer.
  • Actinomycosis, a rare bacterial infection causing abscesses, sometimes in the perianal region.
  • Hidradenitis suppurativa, a chronic inflammatory skin disease leading to abscesses, occasionally in the perianal region.

 

Risk Factors

Certain factors may increase an individual’s likelihood of developing an anal fistula:

  1. Assigned male at birth.
  2. Previous history of perianal abscess.
  3. Inflammatory bowel disease (IBD) like Crohn’s disease.
  4. Past surgeries or radiation therapy in the perianal region.
  5. Weakened immune system or increased susceptibility to infections.
  6. Chronic sexually transmitted infections (STIs).

 

Complications of Anal Fistula

Untreated anal fistulas can lead to persistent infections, causing the infection to seem resolved at the original site before returning and forming new abscesses.

In some cases, untreated fistulas may extend in new directions, leading to more complex fistula patterns, making them harder to repair.

Moreover, long-standing anal fistulas might increase the risk of anal cancer due to chronic inflammation and tissue erosion.

 

Diagnosis and Tests

Healthcare providers typically diagnose anal fistulas through a physical examination. If the external opening is closed, they may need to find the internal opening within the anus, which could require anesthesia for the patient’s comfort.

To locate the internal source of the fistula, providers might use a lighted scope, such as an anoscope or proctoscope, or inject hydrogen peroxide into the external opening, causing bubbles or foam to form at the site of infection, thus confirming the fistula’s presence.

 

Providers may also use imaging tests to understand the fistula’s pathway:

 

  1. MRI: Provides detailed images to map the fistula’s tunnel and its interaction with surrounding structures.
  2. Endoscopic Ultrasound: Similar to MRI, but uses a tiny camera and ultrasound probe inserted into the anus.
  3. Fistulography: X-ray with dye injected into the fistula to highlight its path.

 

Types of Anal Fistulas 

Anal fistulas are classified based on their location in relation to the anal sphincter muscles:

  1. Intersphincteric Fistula: Passes through the internal anal sphincter muscle and then burrows out between the internal and external sphincter muscles.
  2. Transsphincteric Fistula: Travels through both layers of the anal sphincter muscles.
  3. Suprasphincteric Fistula: Passes through the internal sphincter and then loops around the external sphincter.
  4. Extrasphincteric Fistula: Circumvents both sphincter muscles, usually originating from the rectum rather than the anus and unrelated to an anal gland.
  5. Superficial Anal Fistula: Travels from the lower part of the anal canal, bypassing the anal glands, and exits through the nearby skin.

 

Treatment Options

The treatment for anal fistulas typically involves surgery. The complexity of the fistula determines the type of surgery required:

  1. Simple Fistulas: Involving minimal muscle and no branches. Treated with a fistulotomy, where the surgeon cuts through the roof of the fistula to promote healing from the bottom up.
  2. Complex Fistulas: Involving significant muscle, branches, or preexisting conditions complicating the surgery. Treatment may involve techniques like seton drains, endorectal advancement flap, or the LIFT procedure.

Risks and Recovery


After anal fistula surgery, there are some potential risks, such as recurring infection, recurring fistula, and fecal incontinence.

However, these complications are less common with experienced colorectal surgeons. The recovery process generally lasts three to six weeks, with outpatient procedures being common.

 

Living With an Anal Fistula

If you experience anal pain, especially if it persists, it is essential to seek medical attention. Prompt diagnosis and treatment of an anal fistula can lead to more straightforward management and a higher chance of successful healing.

 

Last Word:

An anal fistula is a challenging and painful condition that requires attention and treatment. Understanding its symptoms, causes, diagnosis, and available treatment options can help individuals seek appropriate medical care and improve their quality of life. Remember to consult with a healthcare provider for personalized advice and guidance on managing this condition effectively.

Please note that this article is for informational purposes only and should not replace professional medical advice. Always consult with a healthcare provider for accurate diagnosis and personalized treatment plans.

 

FAQs on Fistula:

 

  1. What is the main cause of fistula?

Fistulas are often caused by infections or inflammations that create abnormal connections between organs or tissues. Common causes include untreated abscesses, Crohn’s disease, diverticulitis, injury, or complications after surgery.

 

  1. Is fistula a serious problem?

Yes, fistulas can be a serious medical issue. They may lead to chronic pain, discomfort, and complications if left untreated. Seeking proper medical attention is crucial for timely management.

 

  1. How can fistula be treated?

Treatment options depend on the type and severity of the fistula. In many cases, surgery is necessary to close the abnormal connection. However, some smaller or less complex fistulas may be managed with medications or minimally invasive procedures.

 

  1. Is fistula a common problem?

Fistulas are not extremely common but can occur in various parts of the body. They are more prevalent in certain conditions such as Crohn’s disease or after certain surgeries.

 

  1. Types of fistula in males:

   In males, fistulas can occur in different regions, including:

  • Rectourethral Fistula: An abnormal connection between the rectum and the urethra.
  • Rectovesical Fistula: An abnormal connection between the rectum and the bladder.
  • Perianal Fistula: An abnormal connection near the anus.

 

  1. How to heal a fistula without surgery?

Healing a fistula without surgery is challenging and often not possible. However, some smaller or less complicated fistulas may respond to conservative treatments like antibiotics, wound care, and managing underlying conditions.

 

  1. Anal fistula symptoms:
  • Common symptoms of an anal fistula include:
  • Persistent pain or discomfort near the anus.
  • Drainage of pus or blood from an opening near the anus.
  • Redness, swelling, and tenderness around the anal area.
  • Recurring abscesses.

 

  1. Anal fistula surgery:

Anal fistula surgery aims to remove the abnormal tunnel and close the connection. Different surgical techniques may be employed based on the complexity and location of the fistula. The procedure aims to promote healing and prevent recurrence.

Remember, these FAQs provide general information about fistulas. It is essential to consult a qualified healthcare professional for personalized advice and proper diagnosis and treatment.

Medically reviewed by Dr. Ramesh Gaddam, M.D.


Discover more from Health Build-Up

Subscribe to get the latest posts sent to your email.

1 thought on “Anal Fistula: Symptoms, Causes, Risk Factors, Treatment”

  1. Pingback: Gallbladder Stones: Symptoms, Causes, Types, Treatment, Diet

Comments are closed.

Discover more from Health Build-Up

Subscribe now to keep reading and get access to the full archive.

Continue reading

Scroll to Top