What Is An Anal Fistula?


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What Is A Perianal or anal Fistula?

An anal fistula is an abnormal tunnel or canal that occurs between the very last part of your GI tract – the final inch or inch and a half or so – and the skin around the anus. In the digestive tract, the most common location for a fistula is around the anus.

Anal fistulas typically form when small glands just inside the anus get clogged and become infected. The clogged glands form a perianal abscess (a painful, pus-filled bump near your anus or rectum), which can then turn into a fistula.

You may see the words “anal” or “perianal” used interchangeably – the “peri” prefix simply means “around” or “about,” and both terms are used to describe fistulas that involve anal tissue.

Professional medical treatment is essential because without proper care, they can do real, lasting harm, including nerve damage, further infections and even kidney failure. And that’s on top of the ongoing, everyday discomfort that most sufferers experience.

Types Of Anal Fistulas

There are a few specific types of anal fistula, and the type that you have may help determine the best medical approach for treatment:

Anorectal Fistulas

These occur when an infected gland in your anus or rectum forms a canal that leads out to the skin around the anal opening.

Rectovaginal Or Anovaginal Fistulas

Similar to anorectal fistulas, these occur when an infection creates a passageway, only in this case, the passageway leads from the rectum or anus to the vagina.

Colovaginal Fistulas

Fistulas can occur even deeper in your digestive tract, leading from the colon to either another organ such as the or bladder, vagina or small intestine, or even reaching to the skin’s outer surface. 

Symptoms of Anal Fistulas

There is a wide range of symptoms that you may experience if you have an anal fistula, though many of these can also be symptoms of other conditions. If you have any of the following, it’s in your best interest to seek help from a medical professional: 

  • Fever, chills and/or fatigue
  • Nausea, vomiting and/or diarrhea
  • Abdominal pain
  • Skin irritation around the anus
  • Constant pain in the area, often worse when sitting, moving or going to the bathroom 
  • Foul smelling discharge near the anus, possibly with pus or blood
  • Pus or blood in the stool
  • Swelling and redness around the anus
  • Bowel incontinence

If you’re experiencing any of these issues, be sure to promptly discuss them with a healthcare provider.

Causes Of Anal Fistulas

In some cases, it can be difficult to identify the specific cause for a fistula – in medical terminology, they’re called idiopathic – but we do know that a large number of them are caused by inflammatory conditions such as Crohn’s disease.

In fact, in one study, 44% of people with Crohn’s disease had one or more features that were consistent with the potential development of fistulas within 6 months of their diagnosis. 

But Crohn’s isn’t the only known cause – there are other possible causes, too:

  • Diverticulitis
  • Tuberculosis
  • Chlamydia
  • Certain cancers
  • Radiation therapy 

What generally happens in the formation of an anal fistula is that one of the glands in the anorectal region becomes abscessed – that is, it develops an infection. There are between 8 and 10 glands in the area that can become infected, and as that infection grows, it creates pressure that pushes outward into the muscle wall and creates a canal.

Treatment Options For Anal Fistulas

Nobody likes talking about these sorts of problems with anyone, but it’s tremendously important that you see a physician if you suspect that you might have a fistula. That’s because successful treatment usually – but not always – requires surgical intervention. 

There are many qualified professionals who can help you find the care you deserve – gynecologists, urologists, urogynecologists and colorectal surgeons are all expertly trained to deal with these sorts of issues on a regular basis. Following your examination, you’ll likely be presented with one of the following treatment options: 

Non-Invasive Treatments

Some patients are fortunate that their condition can actually be treated non-invasively. There are a number of therapies that your physician may try to address your condition, including:  

  • Fibrin glue – You may have heard about how glue is being used more frequently than ever in medicine – it’s used as a liquid bandage, to seal incisions following surgeries and, in fistula repair, to glue the fistula shut. Not all fistulas are candidates for this treatment, but those that are often have excellent results. 
  • Plugs – Collagen is used as more than just a cosmetic filler nowadays. When it comes to repairing a fistula, your physician may inject a collagen matrix into the affected area, sealing it off. 
  • Catheters –  You may be familiar with the idea of a urinary catheter – that is, a tube that drains liquid from the bladder. A catheter in a fistula works in much the same way. These are small tubes or similar devices that are used to drain the infection, typically on smaller fistulas that are actively infected.

Pharmaceutical Treatments

  • Antibiotics. We all know that antibiotics work great on ear infections, eye infections and bacterial infections of all sorts. That’s why it should come as no surprise that antibiotics may also be used to treat the infection that’s causing your fistula. While there is no medication that can eliminate the fistula itself, stopping an active infection is an important step on your path towards healing.
  • Stem Cells. One new treatment that is being tried for Crohn’s sufferers is the use of stem cells injected into the fistula to promote repair – it’s worth asking your physician for more information and to learn if this might be an option for you. 

Surgical Treatments

The most common method to repair an anal fistula is through surgery. The good news is that most procedures are done on an outpatient basis – you’ll be able to go home the same day as your procedure – though patients with deeper or more serious fistulas may require a short hospital stay. Certain significant infections may even require more than one procedure to treat completely. 

No matter what procedure you have done, your colorectal surgeon’s primary goal will be to repair your fistula while protecting your anal sphincter muscles, since damage to them can lead to other issues like incontinence. Fortunately, surgeries today use highly precise instrumentation and advanced technology to minimize the potential for complications while ensuring a greater likelihood of success. 

To reach the fistula, your surgeon will either go one of two routes: 

  • Transabdominally – that is, he or she will make a small incision in the abdominal wall to access it.
  • Laparoscopically –  through a tiny incision and with the use of cameras as guides.


Once the fistula is located, as long as it doesn’t involve the sphincter muscle, the physician will perform what’s called a fistulotomy, cutting it open in a way that promotes healing. If the fistula is more challenging, what the physician may first have to do is install a drain which will remain in place for 6 weeks or longer. After the drain has finished its job, a follow up surgery will be done to complete the repair – usually a fistulotomy or another type of surgery to either cover up or tie off the fistula. 


Setons For Fistulas

When a fistula runs through a considerable portion of the anal sphincter muscle, surgeons might suggest the use of Seton techniques.

What exactly are these techniques? A Seton is a surgical thread that remains inserted in the fistula for a few weeks, keeping it open for drainage and healing purposes. The advantage of this method is that it avoids the need to cut through the sphincter muscles, which can be risky. However, it’s important to note that loose Setons only allow for drainage and are not a complete cure.

In some cases, tighter Setons may be used to gradually cut through the fistula, which can require multiple procedures.

Alternatively, surgeons might recommend performing several fistulotomy procedures, where a small section of the fistula is opened up carefully each time. Ultimately, the best course of treatment will depend on your unique situation, which your surgeon will discuss with you in detail.

Talking To Your Doctor About Fistulas

There are few things less pleasant than surgery, but one of them may be an untreated fistula. Getting help is worth the modest degree of discomfort and embarrassment that come with the territory – the high rate of success from active treatment should encourage you to seek care. 

And if you shudder at the idea of talking with a doctor about such a personal issue, click here for tips on how to have a productive, comfortable, and confident conversation with your physician.