The disease affects populations around the globe and occurs at any age but tends to have a peak incidence between the ages of 15 and 35. Typical presenting symptoms include abdominal pain and diarrhea. The clinical presentation of Crohn's disease fluctuates throughout the course of the disease. Symptoms and signs usually correlate with mucosal inflammation. The pattern of Crohn's disease viewed on endoscopy has been characterized and is associated with a number of mucosal characteristics such as erythema, swelling, nodularity, strictures, aphthoid ulceration and ulcers of variable size and depth.