A variety of conditions arise outside of the gastrointestinal tract that are associated with inflammatory bowel disease (IBD); these are termed extraintestinal manifestations of IBD (table 1). Some of these entities are associated more with Crohn disease than ulcerative colitis, including oral lesions, clubbing, gallstones, pancreatitis, and renal and urologic conditions such as calcium oxalate stones and amyloidosis. Other extraintestinal findings, including skin and eye disorders, are seen with equal frequency in both Crohn disease and ulcerative colitis and may dominate the clinical presentation. Some of the extraintestinal manifestations mirror the course of the luminal disease, while others are unrelated to gastrointestinal activity.
The exact prevalence of extraintestinal findings in patients with IBD has not been extensively studied, although they appear to be common. A study using administrative health data at a tertiary center in Canada estimated that a total of 6 percent of patients with IBD had one of six major extraintestinal diseases that were studied . However, a study from the Mayo Clinic found that 40 percent of IBD patient had one or more extraintestinal manifestations .
The pathogenesis of extraintestinal manifestations is incompletely understood.
A variety of skin disorders may be seen in association with inflammatory bowel disease (IBD).
Erythema nodosum — Erythema nodosum is the cutaneous disorder most frequently seen with ulcerative colitis and Crohn disease, occurring in 4 percent of patients . It typically appears as raised, tender, red or violet subcutaneous nodules that are 1 to 5 cm in diameter (picture 1). The nodules are most commonly located on the extensor surfaces of the extremities, particularly over the anterior tibial area. Biopsy of these lesions shows focal panniculitis, although the diagnosis is most often clinical and biopsy is rarely required. (See "Erythema nodosum".)