Crohn disease is a chronic recurrent inflammatory bowel disorder that can affect any gastrointestinal site from the oral cavity to the anus. The major perianal complications include fissures, fistulas, abscesses, and stenosis, alone or in combination, which affect approximately 35 to 45 percent of patients during the course of the disease. Symptoms can vary from anal pain and purulent discharge to bleeding and incontinence, and can be associated with significant morbidity and impaired quality of life [1-3].
The major perianal complications of Crohn disease will be reviewed here. The role of imaging in diagnosing anal abscesses and fistulas and the medical management of Crohn disease are discussed in detail separately. (See "Overview of the medical management of mild to moderate Crohn disease in adults" and "Overview of the medical management of severe or refractory Crohn disease in adults" and "The role of imaging tests in the evaluation of anal abscesses and fistulas" and "Clinical manifestations, diagnosis and prognosis of Crohn disease in adults" and "Immunomodulator therapy in Crohn disease".)
The American Gastroenterological Association (AGA) guidelines for perianal Crohn disease , as well as other AGA guidelines, can be accessed through the AGA web site at www.gastro.org/practice/medical-position-statements.
Age, race, and disease location are factors associated with perianal complications in Crohn disease. The role of gender is less certain.
- Gender – Conflicting data exist regarding the relationship between gender and the incidence of perianal disease in Crohn disease [5,6]. One report found an increased incidence of fistulas among males , while others found no difference .
- Age – Patients with Crohn disease who are less than 40 years of age are at greater risk for perianal disease . Patients who develop perianal complications at an early age or who have a fistula as the first manifestation of perianal disease may be at increased risk for abdominoperineal resection (proctectomy) [8-10].
- Race – Non-Caucasians and Sephardic Jews (as opposed to Ashkenazi Jews) with Crohn disease have a higher risk for perianal disease [5,7].
- Disease location – Involvement of the perianal region is more common in patients with colonic (particularly rectal) or ileocolonic disease compared to those with disease restricted to the small bowel [1,3,11]. In one study, patients with Crohn colitis were more than three times as likely to develop perianal fistulas as those with ileitis . Patients who have rectal involvement with Crohn disease are at increased risk for surgical resection [8-10].