Psoriatic arthritis is an autoimmune condition which can cause pain, swelling and stiffness in the joints. The immune system, which normally protects the body from infections, begins to turn against the body's own healthy tissues, particularly causing inflammation of joints, as well as tendinous and ligamentous insertions.

Psoriatic arthritis can also present with sausage-like swellings of the fingers and toes; swelling of the heel at the Achilles tendon; and back pain and stiffness. Complications of psoriatic arthritis can include issues with the digestive tract, eyes, liver and heart.

It is linked to an inflammatory skin condition, psoriasis, which causes patches of red and flaky skin often found on the knees, elbows, scalp and behind the ears. Approximately 20 to 30% of those with psoriasis will also have psoriatic arthritis.

Treatment options range from anti-inflammatories, including steroid tablets or injections, through to early initiation of disease modifying anti-rheumatic drugs (DMARDs). Biologic medications are effective in treating psoriatic arthritis. The choice of treatment is usually determined by the presenting clinical features.