How can Crohn disease and ulcerative colitis be linked to arthritis?

Crohn disease and ulcerative colitis are categorized as inflammatory bowel disease, and they are linked to arthritis through a group of conditions known as spondyloarthropathies.1

In as many as 20 percent of patients, these bowel diseases are complicated by this form of arthritis. While the associated joint inflammation typically affects the lower extremities, a significant subset of cases—up to 20 percent—presents with symptoms identical to ankylosing spondylitis, a condition characterized by inflammation of the spine and sacroiliac joints.1

The pathology of this link is often cyclical: the arthritis is typically exacerbated in conjunction with flare-ups of the underlying inflammatory bowel disease and generally persists for several weeks following those gastrointestinal exacerbations. Unlike rheumatoid arthritis, these spondyloarthropathies are not associated with elevated levels of serum rheumatoid factor.1