Reviewed by: HU Medical Review Board | Last Reviewed: January 2018. | Last updated: April 2022
Perianal disease may be the first sign of inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis.1,2 Perianal disease is the term for complications that occur in the rectum or anus. Perianal complications are significantly more common in people with Crohn's disease than ulcerative colitis.3
The rectum is last part of the large intestine (colon). If everything is working normally, your rectum holds stool. As the rectums stretches, it causes a contraction and an urge to have a bowel movement. Anal sphincters are the muscles that allow you to control bowel movements. You have an internal and external sphincter.4
What does perianal disease include?
Abscess and fistula
About 80% of people with Crohn’s disease will have a perianal abscess.1 An abscess is an area of inflammation where pus collects. Abscesses often lead to fistulas. A fistula is a tunnel that develops between 2 structures.1 Over half of fistulas form around the anus.5 A fistula may cause discharge, pain, and incontinence. It can also cause an abscess to form.
Anal fissure is a tear or split at the end of the anal canal. Fissures may be a long-term or short-term problem. Some are painless, others are very painful.
A skin tag is a narrow growth that sticks out of the skin.6 About 37% of people with Crohn’s disease have perianal skin tags.1 There are 2 main kinds of skin tags. Some appear large, swollen, and hard. Others are flat, soft, and painless.
A stricture is a narrowing of a section in the digestive tract. Anal stricture is a spasm of the sphincters. In the rectum, a stricture may be due to the build up of fibrous tissue. Fibrous tissue is made of special proteins, called collagen and fibronectin. These proteins repair damage caused by ulcerations, abscesses, fistulas, or inflammation.1 Perianal strictures can lead to frequent bowel movements, urgency, and the feeling of incomplete bowel emptying.
Hemorrhoids are swollen veins in lower rectum and anus. They cause bleeding, swelling, itching, and discomfort. They are rare in patients with IBD. However, if they occur, they can be hard to treat.1
How common is perianal disease?
About one-third of people with Crohn’s disease have a perianal fistula, fissure, or abscess.7 However, published estimates range from 3.8% to 80%, depending on the population that was studied.1 Perianal complications are less frequent in people with ulcerative colitis, occurring in about 2-5% of patients.3
Perianal disease is more likely for:1,8
- People with inflammation in the colon and rectum
- Elderly individuals
How is perianal disease evaluated?
Often, perianal disease is the first sign of IBD. Therefore, your health care provider may do a rectal exam if he or she suspects that you have IBD.7 If your provider finds signs of perianal disease, the next step is to figure out how what other parts of your digestive tract are affected. Additionally, your health care provider will need to do more tests and procedures to understand the perianal complications.1
Procedures used to study the effects of IBD on your digestive tract—including perianal complications—include:1
Colonoscopy.Colonoscopy is a procedure that allows your doctor to examine your rectum, colon, and ileum. Your doctor will look for signs of IBD.7 Your doctor performs this procedure using a long, thin tube with a very small camera and light. The camera lets your doctor see inside your digestive tract.
Endoscopic ultrasound. In this procedure, a thin, flexible tube (the endoscope) will be inserted into your rectum. At the end of the tube is an ultrasound wand. This wand uses sound waves to create pictures of the rectum and colon.9
Magnetic resonance imaging (MRI).MRI uses magnets and radio waves to take pictures of certain areas of your body. MRI is useful for studying perianal fistulas. It can reveal where the fistula is located and show your provider whether you also have an abscess.10
Examination under anesthesia. Your health care provider may recommend that you have a rectal examination while you are under anesthesia. During this procedure, your provider will visually examine the fistulas and will attempt to feel where the fistula leads using fingers or probes.11
Using any 2 of the last 3 procedures – endoscopic ultrasound, MRI, and examination under anesthesia – is a very accurate way to diagnose perianal disease.1
How is perianal disease treated?
The main goals of treating perianal disease are to avoid:1
- Sepsis, a life-threatening reaction to an infection.
- Surgery for complications that are not causing pain or other symptoms.
- Surgery when there is active inflammation.
- Incontinence, if surgery is necessary.
You will be treated for the underlying IBD.1Medications to treat IBD reduce inflammation.
Each complication is treated differently. However, for any kind of perianal disease, it is important to:1
- Work with your health care provider on finding ways to control diarrhea, either through medication or diet changes.
- Clean the affected area using a sitz bath or shower.
- Use barrier creams that protect the skin around the anus.
Proctectomy is the surgical removal of the rectum. This procedure is done when perianal disease cannot be treated in any other way. About 20% of people with Crohn’s disease eventually need a proctectomy.1