Why Anal Fistula Does Not Heal on Its Own | Causes of Recurrence
Many patients notice a small opening near the anus that repeatedly discharges pus or fluid.
It improves for a few days with medicines, then comes back again.
Because symptoms temporarily settle, people assume the problem has healed.
But an anal fistula is not a surface wound – it is a persistent internal connection.
Unless the tract closes completely, it continues to drain and recur.
Understanding why this happens helps prevent months or years of repeated infections.
1. What Exactly Is an Anal Fistula?
An anal fistula is a tunnel-like tract connecting the inside of the anal canal to the skin outside.
It usually develops after an infection in the anal glands.
1 How It Forms
- A gland inside the anus gets infected
- An abscess (collection of pus) develops
- The abscess drains — naturally or surgically
- A permanent channel remains behind
This channel becomes the fistula tract.
2 Why It Keeps Draining
The inner opening remains connected to the bowel, where bacteria are always present.
As long as this connection exists, fluid repeatedly travels through the tunnel.
2. Why Fistulas Rarely Close Naturally
Unlike a skin cut, a fistula has two openings and an internal lining.
1 Continuous Bacterial Contamination
Every bowel movement exposes the tract to bacteria.
This prevents natural closure.
2 Epithelialized Tunnel
Over time, the tract develops a lining similar to skin.
Once this lining forms, the body cannot seal the passage on its own.
3 Pressure During Defecation
Passing stool increases internal pressure, forcing discharge outward and reopening the tract.
For these reasons, spontaneous permanent healing is uncommon.
3. Why Creams and Antibiotics Only Give Temporary Relief
Many patients use ointments or repeated antibiotics.
1 What Medicines Actually Do
They help by:
- Reducing inflammation
- Controlling infection
- Decreasing pain
2 What They Do NOT Do
They cannot:
- Remove the internal opening
- Close the tunnel
- Prevent recurrence
So symptoms settle briefly, then return once medication stops.
4. Signs the Fistula Is Still Active
Even if pain is mild, the tract remains present when you notice:
- Recurrent swelling near the anus
- Pus or watery discharge
- Staining of undergarments
- Itching or irritation
- Repeated abscess formation
Temporary closure followed by reopening is typical of an untreated fistula.
5. Why Recurrent Abscess Happens
If the external opening closes prematurely, pus accumulates inside again.
This leads to:
- Sudden painful swelling
- Fever
- Need for drainage
The cycle repeats because the internal connection remains.
6. Importance of Proper Evaluation
Fistulas vary in depth and complexity.
Some are simple and superficial, while others pass through important muscle layers controlling continence.
Accurate assessment helps determine appropriate management and prevent complications.
Conclusion
An anal fistula is a persistent internal tunnel, not a superficial infection.
Because the connection to the bowel remains open, it continues to drain and recur despite temporary improvement with medicines.
If symptoms keep returning, it indicates the tract is still present.
If it keeps recurring, it requires proper treatment.
Consult a colorectal surgeon for evaluation when persistent discharge or repeated swelling occurs.