The Bottom Line: Radiograph Imaging of joints may demonstrate periarticular erosive change of the bone in inflammatory arthritides as well as joint space narrowing. In osteoarthritis, periarticular bony spurs develop. Occasionally in psoriatic arthritis joint ankylosis or periarticular osteitis will be present, both distinctive features that do not occur in osteoarthritis or rheumatoid arthritis.
Mease. Inflammatory musculoskeletal disease: identification and assessment. Source: Journal of rheumatology 2011 vol:38 iss:3 pg:557 -561
Summary: it takes clinical acuity to distinguish between inflammation of a joint due to an immunological disease from a crystalline arthritis such as gout or septic arthritis. Experienced rheumatologists even may have problems distinguishing between these disorders.