Understanding Anal Fistulas

What Is an Anal Fistula?

An anal fistula is an abnormal channel or passageway inside the anus leading to the skin outside. This generally develops in the upper part of the butthole area, where the anal glands are located. 

Fistulas typically happen after an anal abscess or infection in the anus. They are more likely to develop in adults than children, especially ones with Crohn’s Disease or a history of perianal abscesses. They are also often chronic and rarely heal unless given medical treatment.

Causes and Risk Factors of Anal Fistulas

Anal fistulas can be caused by a number of things, although most are a result of anal abscesses. They typically form as a reaction to an infected anal gland not healing properly.

However, other anal fistula causes are possible:

  • Crohn’s disease 
  • Actinomycosis, a bacterial infection that can cause abscesses in the perianal region
  • Hidradenitis suppurativa, a chronic inflammatory skin disease that can produce 
  • Tuberculosis affecting the anus
  • A history of perianal abscesses or fistulas


These are also potential risk factors for anal fistula development:

  • Prior radiation therapy or surgery to the anal area
  • Trauma to the anal area
  • Chronic constipation or diarrhoea
  • A weakened immune system
  • Abscesses in the sweat glands of the perianal region
  • Being of the male sex, as it’s more common in men
  • HIV or STI (especially anal and chronic ones)
  • Diabetes 
  • Cancer
  • IBD or inflammatory bowel disease

Signs and Symptoms of an Anal Fistula

The common signs and symptoms of an anal fistula include holes or lumps in the skin around the anus. However, this can be difficult to check on your own. 

The following are other symptoms that may flare up and settle temporarily.

  • Persistent pain or throbbing around the anal region that can worsen with activites like passing motion, coughing or sitting
  • Swelling or redness inside or around your anus, often paired with sensitivity to the touch
  • Discharge of pus or blood near the anus
  • Recurrent abscesses


There are also other less-common symptoms that might accompany these:

  • Low-grade fever
  • Pain while peeing
  • Difficulty holding your bowels (lowered bowel control)

Get Assessed by a Specialist for Anal Fistulas

Book an appointment for proper medical assessment or diagnosis by a colorectal surgeon, especially if you have recurring abscesses or persistent discharge.

How an Anal Fistula Is Diagnosed

Your doctor may perform a visual and physical exam to diagnose your condition. You may also be asked to share your medical history and answer questions like these:

  • How you would describe the pain, if pain is present
  • When the symptoms began
  • If you have had past anal infections or abscesses

You may also be asked to undergo a physical rectal exam for further investigation. Your doctor may use instruments like lighted scopes to check the inside of the anal canal and/or insert a gloved finger in the rectum to manually check for abnormalities.

In some cases, you may also be asked to undergo further imaging like an MRI or ultrasound.

Potential Complications of an Anal Fistula

Both treated and untreated fistulas can have a number of complications:

  • Chronic/persistent infection: A fistula that stems from an abscess or infection may keep the infection active. This can even lead to symptoms like fever if allowed to progress.
  • Formation of multiple tracts: A single fistula may branch out or extend in different directions by creating new channels. This is called a complex fistula and it can be more difficult to treat.
  • Recurrence after treatment: Some fistulas will recur even after treatment. This may require multiple surgeries to address, with a higher chance of further complications.

Treatment of Anal Fistulas

Most anal fistulas do not heal on their own and will require surgical treatment to be properly addressed. The treatment options depend on whether the fistula is simple or complex. A doctor’s examination is necessary to determine the best option for each case.

Surgical Treatment for Simple Fistulas

A fistulotomy is a surgical procedure that can typically be performed as an outpatient procedure. It involves opening the fistula tract so that it can drain properly and heal.

Surgical Treatment for Complex Fistulas

There are several surgical treatments for complex fistulas:

  • Seton drain: This involves passing a surgical thread or tube through the fistula tract. This keeps it open, allowing drainage and encouraging proper healing.
  • Endorectal advancement flap: This uses a flap of tissue from the rectum to close the inner opening of the fistula. This supports healing while also reducing the risk of incontinence.
  • LIFT procedure drain: Also called the ligation of intersphincteric fistula tract, this ties off or ligates the fistula tract in a way that preserves the anal sphincter muscles. The goal is to preserve the muscles and minimise the risk of incontinence.  

Learn more about anal fistula removal.


Other Treatment Approaches for Anal Fistulas

Other treatment approaches that may be recommended for anal fistula patients include antibiotics and management of underlying conditions, like Crohn’s Disease. You may also be advised to maintain good hygiene and avoid constipation to minimise the risk of recurrence.


Recovery and Prognosis for an Anal Fistula

Each patient’s recovery and prognosis varies after anal fistula treatment. Most patients take 4 to 6 weeks to recover, with most of the discomfort being in the first and second weeks. Follow-ups with the doctor are scheduled throughout this period to ensure smooth recovery.

People typically return to work after the second week of recovery, but are generally advised to avoid strenuous activity for as long as 6 weeks. There is a risk of recurrence, but the prognosis is generally good if the condition has been treated and heals properly. 

Prevention and Management of Anal Fistulas

Anal fistulas may not be entirely preventable, but the risk of developing anal fistulas can be lowered. You can follow these tips to reduce your risk:

  • Seek prompt treatment for abscesses or infections
  • Manage bowel health and avoid constipation or diarrhoea
  • Properly manage chronic conditions like Crohn’s
  • Practise good hygiene in the anal area

Book an Appointment for Anal Fistula Diagnosis or Treatment

Schedule a consultation with our colorectal specialist for accurate diagnosis and appropriate treatment. Early evaluation can help manage the condition effectively and prevent complications.