Fistulizing Crohn’s disease is a subset of Crohn’s disease characterized by the formation of fistulas, which are atypical connections between different types of tissues.

Fistulas can also be atypical openings in your skin that connect to internal tissues.

Not everyone with Crohn’s disease will have fistulas, but it’s not uncommon. According to the Crohn’s & Colitis Foundation of America, between 35% and 50% of adults with Crohn’s will eventually have one or more fistulas.

Let’s take a look at what it means to have fistulizing Crohn’s disease and what can be done about it.

Crohn’s disease is a type of inflammatory bowel disease that can affect any part of your gastrointestinal tract. You can have Crohn’s at any age, but the Crohn’s & Colitis Foundation notes that it’s usually diagnosed between the ages of 15 and 35.

There are many types of Crohn’s disease. These types are generally categorized by what parts of your gastrointestinal tract are affected:

  • Ileitis affects your small intestine throughout.
  • Gastroduodenal Crohn’s disease affects your stomach and the beginning of your small intestine.
  • Jejunoileitis affects the middle section of your small intestine.
  • Ileocolitis affects the end of your small intestine and the beginning of your large intestine.
  • Granulomatous Crohn’s disease affects only your large intestine.

Fistulas are commonly associated with granulomatous Crohn’s disease. However, fistulas can also form in other types of Crohn’s in more severe cases.

“Perianal” means that something relates to the area in or around your anus. If you have perianal fistulizing Crohn’s disease, this means that your Crohn’s includes fistulas in or near your anus.

Perianal fistulizing Crohn’s disease accounts for about a third of all Crohn’s disease cases.

Perianal fistulas frequently begin as sores or abscesses on the inside of your anus. These can grow until they reach the skin near your anus, creating a fistula.

The perianal area is the most common area for fistulas to form for people with Crohn’s disease, but fistulas can also form in other places and don’t need to create an opening in your skin.

Fistulas can be internal, connecting your small and large intestine, for example, or connecting your intestine to your bladder.

Some of the symptoms common to all types of Crohn’s include:

If you have fistulas, you may have additional symptoms depending on where the fistulas are located, according to the Crohn’s & Colitis Foundation.

Perianal fistulas might start out feeling like a painful bump or a sore. As it opens up, fluid or stool might start to drain from the opening.

Internal fistulas could cause a variety of symptoms depending on their location, but symptoms can include:

Experts aren’t totally sure what causes Crohn’s disease. It might be caused by an autoimmune reaction, caused by a genetic disease, or triggered by something in the environment. Possibly, it’s caused by some combination of the three.

Crohn’s is an inflammatory disease. Inflammation is one of your body’s natural mechanisms for defending itself from infection.

Prolonged or severe inflammation within your gastrointestinal tract can lead to sores along the walls of your tissues. Pus can collect in these sores, causing them tunnel outward from one tissue into another.

Language matters

You’ll notice that the language used to share stats and other data points is pretty binary, fluctuating between the use of “men” and “women.”

Although we typically avoid language like this, specificity is key when reporting on research participants and clinical findings.

Unfortunately, the studies and surveys referenced in this article didn’t report data on, or include, participants who were transgender, nonbinary, gender nonconforming, genderqueer, agender, or genderless.

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According to the Crohn’s & Colitis Foundation, Crohn’s is usually diagnosed in people between the ages of 15 and 35, although it can occur at any age. It’s just as likely to occur in men as in women.

Anywhere from a third to half of all people with Crohn’s will eventually develop a fistula.

Fistulas are most common in the perianal area.

When you have fistulas from Crohn’s, it usually indicates more severe disease and requires more intensive management. Oftentimes, fistulas need to be repaired surgically.

Fistulas connecting to your rectum can lead stool to drain involuntarily from your body. Stool might also leak into other tissues, which can lead to discomfort and an increased risk of infection.

For some people, a fistula will be the first sign of having Crohn’s disease. For others, a Crohn’s diagnosis will already be in place before a fistula first appears.

Testing to make an initial Crohn’s diagnosis might include:

If you have a fistula, it needs to be treated in order to avoid complications.

Infliximab is a biologic medication that’s often used as a first step toward helping fistulas heal.

Another biologic that’s sometimes used is adalimumab (Humira). This drug is used to treat a variety of inflammatory conditions.

Antibiotics are sometimes used in combination with biologics to help treat some of the symptoms of fistulas. Metronidazole is one such antibiotic, but there are others.

If medications aren’t successful, surgical treatments are also available. These can include:

  • fistulotomy (opening the fistula so that it heals as a flat scar)
  • fistulectomy (complete removal of the fistula)
  • diverting ostomy (creating a new opening to remove bodily waste)
  • proctectomy (complete or partial removal of the rectum)

Whether or not you have a Crohn’s diagnosis, you should get medical help if you believe you have a fistula.

Fistulas don’t heal on their own. They can be entryways for bacteria and other infectious microbes into your body, and they can prevent some of your bodily functions from working effectively.

A analysis from 2020 found that among people between the ages of 5 and 24 who have Crohn’s disease, reducing or eliminating the use of steroids (steroid sparing treatment) led to a 59% decreased risk of developing perianal fistulizing complications.

These results still need further study — including among other age groups — but they seem to indicate that certain treatments could help prevent fistulas from forming for people with Crohn’s.

Crohn’s disease is a type of inflammatory bowel disease. It can affect any part of your gastrointestinal tract but is often found throughout your small and large intestines.

Prolonged intestinal inflammation caused by Crohn’s can lead to the formation of fistulas. The most common type are perianal fistulas.

Fistulas can be painful, debilitating, and a source of future complications. If you think you have a fistula, it’s important to make an appointment with a doctor.