Inflammatory

• Connective tissue disease, eg, rheumatoid arthritis, systemic lupus erythematosus, scleroderma, Sjögren's syndrome, adult Still's disease
• Seronegative spondyloarthropathy, eg, reactive arthritis (Reiter's syndrome), psoriatic arthritis, ankylosing spondylitis, inflammatory bowel disease
• Crystal-induced, eg, gout, pseudogout
• Inflammatory osteoarthritis
• Lyme disease
• Paraneoplastic syndrome (especially in elderly, eg, hypertrophic pulmonary osteoarthropathy)

Noninflammatory

• Osteoarthritis (degenerative joint disease)

• Arthritis, general DDx