PsoriasisArthritis

PsoriasisArthritis, also known as psoriatic arthritis (PsA), is a chronic inflammatory rheumatic disease that occurs in people who have psoriasis. It can affect joints, entheseal sites, and the spine, with a range from mild to highly inflammatory disease. Skin psoriasis may come before, at the same time, or after joint symptoms.

Joint involvement can include asymmetric oligoarthritis of small joints, dactylitis (sausage digits), enthesitis at sites such as the Achilles tendon insertion, and axial disease involving the spine. The pattern varies, and many patients have both skin and joint manifestations.

The cause is not fully understood; genetic predisposition with HLA-B27 is common in axial disease. Immune pathways involving TNF, IL-17, and IL-23 drive inflammation, and environmental triggers such as infections or trauma may contribute. The disease is considered part of the broader family of inflammatory rheumatic diseases known as spondyloarthritides.

Diagnosis is clinical, supported by CASPAR criteria. Laboratory tests help exclude other conditions, and imaging (X-ray, ultrasound, MRI) aids assessment of joints and entheseal involvement. Rheumatoid factor is typically negative; inflammatory markers may be elevated, but there is no single diagnostic test for PsA.

Treatment aims to control symptoms and prevent joint damage. Management typically includes NSAIDs for pain, corticosteroid injections for inflammation, conventional DMARDs such as methotrexate, and biologic DMARDs targeting TNF, IL-17, or IL-23; PDE4 inhibitors like apremilast; and dermatologic therapies for skin disease. Physical therapy and regular exercise support function.

Prognosis varies with disease severity and access to early, targeted therapy. PsA can be persistent and progressive, but many patients achieve good control. Comorbidities include cardiovascular disease, metabolic syndrome, and depression.