What Triggers a Perianal Fistula? Who's at Risk?

"Why me?" — that's usually the first question my patients ask after I diagnose a fistula. The honest answer: most of the time, there isn't a single culprit. But over the years, I've seen the same common threads come up again and again in similar cases. Knowing them helps you understand your own risk and prevent a recurrence.

The main mechanism: a blocked gland, a burst abscess

Almost every fistula starts at the same point: one of the secretory glands in the anal canal becomes blocked and inflamed. When the resulting abscess drains, roughly half the time it leaves a permanent tunnel behind. So the real question isn't "why does a fistula form?" — it's "why do the glands get blocked and why does an abscess develop?" This is exactly where the triggers come in.

Factors that increase the risk

A prior perianal abscess

By far the strongest factor. In a patient with a history of an abscess, discharge that starts months later is a fistula until proven otherwise. That suspicion grows even stronger in patients who have had a second abscess.

Crohn's disease and inflammatory bowel disease

Crohn's disease is an inflammation that can affect the full thickness of the bowel wall, and a fistula is almost its signature complication. In young patients, or those with multiple or recurring fistulas, Crohn's disease should always come to mind, and we work together with gastroenterology when needed. This distinction is critical, because treating a Crohn's fistula isn't just about surgery.

Diabetes and conditions that suppress immunity

Uncontrolled diabetes, long-term use of cortisone-like drugs, and chemotherapy all make it easier for an abscess to develop and slow down healing. That's why, in my diabetic patients, I always plan fistula treatment together with blood sugar control.

Smoking

Smoking narrows small blood vessels and impairs tissue nourishment; it's the least talked-about factor, yet it increases both the development of a fistula and the risk of recurrence after surgery. Quitting before treatment visibly improves the quality of the outcome.

Prolonged sitting, constipation, and toilet habits

Long hours spent sitting at a desk, toilet sessions stretched out by phone use, and chronic constipation increase local pressure and moisture, preparing the ground. None of these alone causes a fistula, but combined with other factors they complete the picture.

Rarer underlying causes

Tuberculosis, prior pelvic radiotherapy, previous surgery in the area, and birth injuries can also set the stage for a fistula. For a special type that develops between the vagina and bowel in women, see the article on rectovaginal fistula.

Is it poor hygiene? Let's correct a myth

Some of my patients blame their own cleanliness and feel ashamed about it. Let me say this plainly: a fistula is not caused by dirtiness. A blocked gland is an anatomical and inflammatory event; it isn't your fault. Ironically, the opposite — excessive cleaning, aggressive wiping, scented products — can actually cause harm by irritating the skin.

How can I reduce my risk?

There's no magic formula, but the equation is simple: avoid constipation (fiber + water), don't linger on the toilet, break up long stretches of sitting, cut back on smoking — ideally quit — and if you have diabetes, take its control seriously. Most important of all: if you've had an abscess, don't dismiss discharge that starts in the following months as "leftover residue"; a fistula caught early through its symptoms is the easiest one to treat.

Frequently asked questions

Is a fistula hereditary?

It isn't a directly inherited condition. However, there can be an indirect predisposition in underlying conditions with a familial tendency, such as Crohn's disease.

Does spicy food cause a fistula?

No. Spicy food can worsen existing symptoms (burning, irritation) but doesn't create a tunnel. Diet's real role in fistulas is preventing constipation.

Does lifting weights at the gym trigger it?

Heavy lifting increases intra-abdominal pressure and is a meaningful factor for hemorrhoids; it isn't a direct cause of a fistula. During an active abscess, however, heavy exercise should be avoided.

I had an abscess; how do I know if a fistula has developed?

If, in the following weeks, you notice discharge, soreness, or an opening in the skin that won't close in the same area, a fistula may have developed. When in doubt, an examination is the only way to know; caught early, incision-free laser treatment is possible in most cases.

We're happy to evaluate your risk factors together at our clinic in Levent: 444 8 623.

Sources

• American Society of Colon and Rectal Surgeons (ASCRS), fascrs.org
• NHS — patient information on Anal Fistula, nhs.uk