Rheumatoid arthritis (RA) is the most common cause of autoinflammatory polyarthritis. The disease occurs in all ethnicities with reported prevalence 1-2% in Caucasians and 0.3-0.4% in Chinese. Peak age of onset is 30 to 58 years old (1) with a female-to-male ratio of 3:1.

RA is usually insidious in onset of pain, swelling and morning stiffness in small hand joints including proximal interphalangeal (PIP) joints, metacarpophalangeal (MCP) joints, and the wrist. Unlike osteoarthritis, distal interphalangeal (DIP) joints are usually spared. The natural course of disease may result in joint deformity with functional loss. Disease modifying anti-rheumatic drugs (DMARD) are the cornerstone of treatment for symptom alleviation, prevention of joint damage and other complications.