Prof. Dr. Emre Sivrikoz

Specialty Area

Anal Fistula

An anal fistula is an abnormal tunnel that forms between the inner part of the anal canal and the skin around the anus. The most common sign is persistent or recurrent purulent discharge from a small opening around the anus. It does not heal on its own without treatment.

Information

What Is an Anal Fistula?

An anal fistula is an abnormal tunnel that forms between the inner part of the anal canal and the skin around the anus. It most often develops when a previous anal abscess fails to heal properly. A fistula can cause continuous or intermittent discharge from the anus and does not heal on its own.

With proper assessment and the right choice of treatment, a lasting solution can be achieved.

How Does an Anal Fistula Form?

Most anal fistulas are caused by a cryptoglandular infection. The process usually progresses as follows:

1 Infection of anal glands

An infection develops in the anal glands.

2 Anal abscess

The infection may turn into an abscess.

3 Fistula tract

Even if the abscess drains, a persistent tract may remain.

Less common causes

  • Crohn’s disease
  • Tuberculosis
  • After radiotherapy
  • Trauma or surgical procedures

Who Gets an Anal Fistula?

An anal fistula is more common in the following groups:

More common in men
Ages 20–50
History of anal abscess
Crohn’s disease
In Crohn’s disease, fistulas may follow a more complex course.

What Are the Symptoms of an Anal Fistula?

Most common symptoms

  • Persistent or recurrent purulent discharge from an opening in the skin near the anus
  • Soiling of underwear due to discharge
  • Foul odor around the anus
  • Intermittent pain and swelling
  • Recurrent anal abscesses
  • Rarely, fever
Pain relief after drainage does not mean the condition has healed.

Is an Anal Fistula Dangerous?

An anal fistula is usually not life-threatening. However, if left untreated, it can lead to ongoing infection, recurrent abscesses, a more complex branching fistula tract, and a significant reduction in quality of life. Early assessment is therefore important.

Can an Anal Fistula Heal on Its Own?

No. An anal fistula does not close spontaneously. Antibiotics may provide temporary relief, but they do not offer a permanent cure. Definitive treatment is most often surgical.

How Is an Anal Fistula Diagnosed?

The diagnosis is often made through a physical examination. To assess the fistula’s course and its relationship to the sphincter muscles, a pelvic MRI and, in some cases, an examination under anesthesia may be required. This evaluation is critical for choosing the most appropriate surgical approach.

1 Examination

The external opening and tract are assessed.

2 Pelvic MRI

The direction of the tract and its relation to muscles becomes clear.

3 Planning

Sphincter-preserving options are preferred when appropriate.

Treatment for Anal Fistula

Treatment is planned according to the fistula type, location, and its relationship with the anal sphincter muscles. The goal is to close the fistula permanently while preserving continence.

FistulotomyMay be effective for simple, low fistulas.
Seton placementMay be used in complex fistulas for infection control and staged treatment.
Sphincter-preserving techniquesOptions such as laser ablation, LIFT, or advancement flap may be suitable in selected patients.
There is no single “standard” technique for every fistula. Treatment is individualized.

What Is the Recovery Like After Surgery?

  • Most patients are discharged the same day or the following day.
  • Some discharge in the first days can be considered normal.
  • Warm sitz baths and wound care are usually recommended.
  • Recovery time varies depending on the technique used.
  • Regular follow-ups help reduce the risk of recurrence.

Can an Anal Fistula Recur?

There is a risk of recurrence depending on the complexity of the fistula. Factors that may increase recurrence include a high or branching tract, Crohn’s disease, an unsuitable surgical technique, and inadequate preoperative planning. With the right approach in experienced hands, success rates are high.

When should I see a doctor?

  • If you have persistent or foul-smelling discharge from the anus
  • If recurrent anal abscesses occur
  • If swelling and pain recur around the anus
  • If you previously had fistula surgery and symptoms have returned

When assessed early, an anal fistula may be treated with simpler, sphincter-preserving options.

FAQ

Frequently Asked Questions About Anal Fistula

An anal fistula is an abnormal tunnel between the inside of the anal canal and the skin around the anus. The most common symptom is persistent or recurrent discharge from the anus.
The most common cause is an anal abscess that develops after an infection of the anal glands. Less commonly, it may be related to Crohn’s disease, tuberculosis, trauma, or radiotherapy.
No. An anal fistula does not close spontaneously. Antibiotics may provide temporary relief but do not offer a permanent solution.
Not always. Other anorectal conditions can cause similar symptoms. A medical examination is required for an accurate diagnosis.
It is usually not life-threatening. However, if untreated, it may lead to recurrent infections and abscesses, significantly reduce quality of life, and become more complex.
Diagnosis is often made on examination. A pelvic MRI and, in some cases, an examination under anesthesia may be needed to evaluate the tract and its relation to the sphincter muscles.
The goal is to treat the fistula definitively while preserving continence. For this reason, the method is planned individually.
A seton is a material that can be placed within the fistula tract, especially in complex cases, to help control infection and allow safe surgical planning. Suitability is determined by examination and imaging.
A high or branching tract, Crohn’s disease, and an unsuitable technique can increase recurrence risk. Proper planning and regular follow-ups help reduce recurrence.
If you have foul-smelling discharge, recurrent abscesses, swelling, or pain, you should seek medical advice without delay. Early assessment increases the chance of simpler, sphincter-preserving options.
Real Reviews

Patient Information Note

This content is for general informational purposes only and does not replace medical diagnosis or treatment. If you experience symptoms such as discharge from the anus, recurrent abscesses, or pain, you should consult a general surgery specialist. Treatment for anal fistula is individualized.

Author

Prof. Dr. Emre Sivrikoz, Specialist in General Surgery
Clinical experience in colorectal surgery and proctology

Medical Review

Last updated: 02 / 2026

References

  • American Society of Colon and Rectal Surgeons (ASCRS)
  • UpToDate – Anal Fistula
  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

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