Chronic inflammatory arthritis that affects around 8% of people with psoriasis
Aetiology
Occurs in approximately 8% of individuals with psoriasis, irrespective of the severity of the skin disease
Can occur at any age, but it most commonly begins between the ages of 30 and 50
10-15% of patients can have PsA without psoriasis
Clinical features
Features in history and examination
Personal or family history of psoriatic rash - typically on extensor surfaces
Predominantly affects joints of hands and feet
Dactylitis (a sausage-like swelling affecting one or two digits) is a distinctive feature that occurs in around 25% of patients
Eye disease
Nail changes, include pitting, yellowing, ridges or oncholysis
Enthesopathy including Achilles tendonitis
Patterns of presentation
Symmetrical polyarthritis, similar to rheumatoid arthritis (20–40%)
Asymmetric oligoarthritis (30–55%)
Distal interphalangeal joint disease (7–17%)
5% of patients have a particularly aggressive and destructive form of the condition known as arthritis mutilans - usually occurs in the hands, involves the reabsorption of bone and collapse of soft tissue
Arthritis mutilans is a particularly aggressive and destructive form of the condition affecting 5% of patients
Involves the reabsorption of bone and collapse of soft tissue; telescoping of the digits is seen