What Is Perianal Crohn’s Disease?

Medically Reviewed by Minesh Khatri, MD on June 23, 2022
4 min read

Crohn’s disease is a complex condition. One reason for this is that it can affect any area of your digestive, or GI, tract. That tract starts at the mouth and travels down the esophagus, through the bowels to the rectum, and ends at the anus. This is where a complication known as perianal Crohn’s can strike.

No matter where you have Crohn’s, you can get perianal Crohn’s disease. This is when the condition causes damage, like strictures and fistulas, in the area around the anus. Strictures happen when repeated flare cycles cause scar tissue to form. This tissue builds up to the point where the area becomes narrow. When this happens near your anus, it makes it hard for you to pass gas or poop. A fistula forms when Crohn’s inflammation creates sores on the walls of affected areas. The sores go through the entire wall, making a tunnel that drains pus into other parts of the body.

Perianal Crohn’s is often a sign that you have severe Crohn’s. It’s more of a challenge to treat and often requires surgery. It can go into remission, but it also often relapses. Only about a third of people who have it are in remission after a year on maintenance treatment.

About 25% of adults with Crohn’s will have perianal disease, though some research puts the number as high as 80%. Anywhere between 17% and 43% of people develop anal fistulas, one of the most serious problems. In about 5% of cases, the perianal area is the only area affected.

Among kids with Crohn’s, it’s estimated that between 13.6% and 62% have perianal disease.

Perianal Crohn’s affects similar numbers of men and women, but women are at greater risk for further complications in the vaginal wall.

It’s not completely clear who might be at a greater risk for perianal Crohn’s. Research suggests that both genetics and the makeup of a person’s gut bacteria may be behind its development. Scientists are working to learn more about the role of genetics as the science of genetics itself develops.

If you have ileitis, or inflammation in the lower part of your small intestine, your risk of perianal Crohn’s may be greater. Other things that may have a link to this complication include being diagnosed with Crohn’s before age 20 and having a more complicated form of the disease.

Perianal Crohn’s can cause three levels of damage. The first is called tissue destruction. You may get anal fissures (cuts), skin tags, and deep ulcers. The second causes abscesses, which often go hand-in-hand with perianal fistulas. Fistulas can be simple or complex. Complex fistulas have many tunnels that sometimes extend to other organs like the bladder. The third level is rectal stricture. This is often the result of chronic inflammation.

Symptoms vary from person to person. You may be constipated or be unable to control your bowel movements (fecal incontinence). You may have serious, repeated infections. Itching and bleeding are common. Perianal Crohn’s can cause pain, yet not everyone has pain, even when they have fissures.

In some people, perianal Crohn’s is mild. In others, it’s severe and impacts quality of life. It can

interfere with your sex life and take a deep emotional toll.

It takes a team approach, usually a surgeon and gastroenterologist working together, to diagnose and treat perianal Crohn’s. A gastroenterologist who specializes in Crohn’s will see outward signs of mild perianal disease during a physical exam.

To correctly diagnose a fistula and other damage, you’ll need what’s called an internal exam under anesthesia, or EUA. This should only be done by a surgeon experienced in perianal Crohn’s. During an EUA, the surgeon will look for and drain any abscesses; find and, if needed, suture a fistula; and check to see if nearby structures, such as the vaginal wall in women and the scrotum in men, are affected. The entire procedure is considered the first step in treatment – when done before medication is started, the overall outcome is better.

Medications are key to putting perianal Crohn’s in remission. These include

Immunosuppressive drugs:Azathioprine and 6-mercaptopurine

Biologic drugs:Adalimumab, certolizumab, and infliximab

Very small studies have found that nutritional therapy may also help, especially to heal fistulas.

Researchers are looking into new potential treatments. With hyperbaric oxygen therapy (HBOT), you have daily sessions to inhale pure oxygen in a chamber with air pressure that’s 1.5 to 3 times higher than normal. This boosts the oxygen levels in your blood to help speed tissue healing. In a recent small study, fistulas healed in 65% of people who tried this method.

Another study looked at applying or injecting mesenchymal stem cells (MSC) directly to the affected areas. Fistulas healed in half the people studied. We need more in-depth trials to know if these therapies will work safely for large numbers of people. But they offer hope that effective treatment will be found.

It takes a prompt and careful diagnosis and ongoing follow-up from an experienced team to manage perianal Crohn’s. Because it may return and require surgery, it helps to care for your emotional as well as your physical needs. Get support from a therapist to protect your mental health as soon as you start to feel overwhelmed. To boost your sense of being in control, learn as much as you can about your condition, including new treatments on the horizon.