Overview
Psoriatic arthritis is an inflammatory arthritis associated with psoriasis. It can affect peripheral joints, the spine, and the points where tendons attach to bone (entheses).

Causes and risk factors
Immune dysregulation and genetic factors play a role. It often occurs in people with psoriasis or a family history of psoriasis.

Symptoms
Joint pain, swelling, and stiffness; dactylitis (swollen “sausage” digits); nail changes; and back pain. Symptoms can be asymmetric and vary widely.

Diagnosis
Diagnosis is clinical, supported by imaging and lab tests to rule out other conditions. There is no single definitive test.

Treatment
Treatment includes NSAIDs, DMARDs, biologics, and physical therapy. Managing skin disease is also important.

When to seek care
Joint symptoms in someone with psoriasis should be evaluated early to prevent joint damage.