Perianal Crohn's disease: classification and clinical evaluation.

Perianal manifestations are common in patients with Crohn's disease and include skin tags and haemorrhoids, fissures, ulcers, abscesses, fistulas, stenosis or cancer. Primary lesions include Crohn's fissures and cavitating perianal ulcers. Secondary lesions include deep abscesses, fistulas and strictures. A good classification and anatomical description of these conditions is crucial before embarking on any kind of (medical or surgical) therapy, as this greatly influences management. This review analyses and discusses current classifications of any perianal form of Crohn's disease.