The complexity of the differential diagnosis for the inflammatory arthritides.

Increasing evidence reveals that patients who have inflammatory arthritis experience structural damage early in the course of the disease. To effectively minimize the destruction caused by chronic inflammation, it is necessary to identify these patients soon after the onset of symptoms. However, differential diagnosis is not always straightforward. This article reviews selected underlying issues that complicate the differential diagnosis of the inflammatory arthritides and describes key features of the typical presentations for 3 of the commonly seen forms of inflammatory arthritis--rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis.