2.1
Psoriatic arthritis is an inflammatory arthritis affecting the joints and connective tissue and is associated with psoriasis of the skin or nails. The prevalence of psoriasis in the general population is estimated at 2% to 3%. The prevalence of inflammatory arthritis in people with psoriasis is estimated at up to 30%. At least 20% of people with psoriasis have severe psoriatic arthritis with progressive joint lesions. Psoriatic arthritis is a progressive disorder ranging from mild synovitis to severe progressive erosive arthropathy. People with psoriatic arthritis presenting with oligoarticular disease progress to polyarticular disease and a large percentage develop joint lesions and deformities, which progress over time. Despite clinical improvement with current disease-modifying antirheumatic drug (DMARD) treatment, joint damage has been shown radiologically in up to 47% of people with psoriatic arthritis at a median interval of 2 years.