Psoriatic Arthritis
Overview
Plain-Language Overview
Psoriatic arthritis is a type of inflammatory arthritis that affects some people who have the skin condition psoriasis. It primarily involves the joints and the areas where tendons and ligaments attach to bone, causing pain, swelling, and stiffness. This condition can affect any joint but often targets the fingers, toes, and spine. People with psoriatic arthritis may notice changes in their nails, such as pitting or separation from the nail bed. The inflammation can lead to joint damage if not treated, impacting mobility and quality of life. It is a chronic condition, meaning it lasts a long time and may have periods of worsening symptoms.
Clinical Definition
Psoriatic arthritis is a chronic, immune-mediated inflammatory arthritis associated with psoriasis, characterized by synovitis, enthesitis, and dactylitis. It results from a complex interplay of genetic predisposition, including HLA-B27 and other susceptibility genes, and environmental triggers leading to aberrant activation of the immune system. The disease affects peripheral joints, axial skeleton, and entheses, causing joint pain, swelling, and stiffness. It is classified as a seronegative spondyloarthropathy due to the absence of rheumatoid factor. Radiographic findings include asymmetric joint involvement, pencil-in-cup deformities, and new bone formation. The major clinical significance lies in its potential to cause irreversible joint damage and disability if untreated.