Could a persistent, painful abscess near your bottom actually be something far more serious than it appears? That question stops many patients cold — and rightly so.
Anal fistula is one of those conditions that gets dismissed, ignored, or embarrassingly avoided until it becomes impossible to live with. Yet it is far more common than most people realise, and with the right specialist care, it is completely treatable. This guide covers everything you need to know — written so you can walk into a consultation fully informed.
What Exactly Is an Anal Fistula?
An anal fistula is an abnormal tunnel-like channel that forms between the inside of the anal canal and the skin surrounding the anus. Think of it as a small, infected passageway that the body creates — usually after an abscess bursts or fails to heal properly. This channel collects bacteria, causes recurring infections, and simply does not close on its own without medical intervention.
Roughly 50% of people who develop a perianal abscess will go on to develop an anal fistula. It is not a condition you can wait out.
The Root Causes
Infected Anal Glands: The anal canal contains small glands that can become blocked and infected. When the infection spreads into surrounding tissue, an abscess forms. If that abscess does not drain completely, the resulting channel becomes an anal fistula.
Crohn's Disease: Inflammatory bowel disease — particularly Crohn's — is responsible for a significant proportion of complex fistulas. Patients with Crohn's require specialised management because the tissue is already compromised.
Previous Anorectal Surgery: Scarring or incomplete healing after haemorrhoid surgery or other anorectal procedures can create abnormal channels.
Tuberculosis (TB): In India, TB remains a notable cause of anal fistulas, especially in high-burden areas across Maharashtra, including parts of Mumbai, Navi Mumbai, and Thane. A TB-related fistula requires anti-TB therapy alongside surgical treatment.
Other Causes: Radiation therapy to the pelvis, sexually transmitted infections, trauma, and in rare cases, colorectal cancer can also lead to fistula formation.
Recognising the Symptoms
Patients frequently describe their symptoms as "embarrassing" or "impossible to explain." But recognising the warning signs early is critical to avoiding repeat infections and surgical complications.
- Persistent pain and discomfort around the anus, particularly when sitting or during bowel movements
- Swelling and redness near the anal opening, sometimes with a small external opening that oozes pus, blood-stained fluid, or faecal matter
- Recurring abscesses — if you have had two or more perianal abscesses treated at different times, there is a high probability that a fistula is already present
- Fever and general malaise accompanying an active infection — do not ignore a low-grade fever combined with anal pain
- Skin irritation, itching, and a foul smell due to discharge — signs of an underlying structural problem, not poor hygiene
How Is It Diagnosed?
Diagnosis begins with a thorough clinical examination. A colorectal surgeon will perform a digital rectal examination to feel for the internal opening of the fistula. Most fistulas are identifiable at this stage.
Proctoscopy: A small instrument is used to examine the inside of the anal canal and lower rectum, helping the surgeon map the internal opening accurately.
MRI Fistulogram: For complex, deep, or recurrent fistulas, an MRI of the pelvis provides a detailed 3D map of the fistula tract in relation to the sphincter muscles. This is essential for planning surgery without risking incontinence.
Endoanal Ultrasound: A specialised ultrasound probe placed inside the anal canal produces real-time images of the sphincter complex and fistula tract — valuable when MRI is contraindicated.
Examination Under Anaesthesia (EUA): Where the fistula is deep or the patient cannot tolerate a clinic examination, EUA allows the surgeon to probe and map the tract under controlled conditions.
Treatment Options Explained
There is no medication that cures an anal fistula. Surgery is the definitive treatment — but the exact procedure depends on the fistula's complexity, location, and its relationship to the anal sphincter muscles.
Fistulotomy: The most common procedure for simple, low fistulas. The surgeon lays open the entire fistula tract, allowing it to heal from the inside out. Success rates exceed 90% for uncomplicated fistulas. Recovery typically takes four to six weeks.
Seton Placement: For high or complex fistulas that involve a significant portion of the sphincter muscle, a seton (a thread or drain) is passed through the tract. It gradually cuts through or drains the tissue over several weeks, protecting sphincter function throughout the process.
LIFT Procedure (Ligation of Intersphincteric Fistula Tract): A sphincter-preserving technique that is gaining popularity for transsphincteric fistulas. It has a low risk of incontinence and a good long-term success rate.
Video-Assisted Anal Fistula Treatment (VAAFT): A minimally invasive, scope-based approach where the surgeon visualises and treats the fistula tract from the inside using a fistuloscope. Patients experience less post-operative pain and faster recovery.
Advancement Flap Repair: Used for complex or recurrent fistulas, this technique uses a flap of healthy rectal tissue to cover the internal opening. It is particularly effective in Crohn's-related fistulas.
Anti-TB Treatment: When tuberculosis is the underlying cause, the patient must complete a full course of anti-TB medication before or alongside surgical intervention.
If you have had two or more perianal abscesses, a fistula is likely already present — even without an obvious external opening.
Recovery and What to Expect
Most patients undergoing fistula surgery are back to light activity within one to two weeks. Sitz baths (sitting in warm water two to three times daily) significantly reduce discomfort and keep the wound clean. A high-fibre diet and adequate hydration prevent constipation and strain. Your surgeon will schedule regular follow-ups to monitor healing and catch any recurrence early.
Consult Dr Akash N Bagade
Ignoring anal fistula symptoms will not make them disappear — it will make them worse. Dr Akash N Bagade is an experienced colorectal and laparoscopic surgeon serving patients across Mumbai, Navi Mumbai, and Thane, offering expert evaluation and the full range of surgical treatments under one roof with personalised care.