Arthritis associated with Psoriasis
Psoriatic arthritis affects 5-40% of people with skin psoriasis. The cause is partly genetic with men and women affected equally and the most common age of onset is 20 to 40 years.
Psoriasis usually precedes the arthritis, but in 10% the arthritis is the first problem encountered. 80% of patients with arthritis have nail deformities, compared to 20% of patients with “uncomplicated” psoriasis.
The pattern of joints involved varies, from the spine to a presentation more typical of rheumatoid arthritis with the hands and feet affected. There is a particular predeliction for the end finger joint next to the nail, and for involvement of a whole finger, including tendons and other tissues, known as “dactylitis”. X-Rays show a characteristic destrucutive type of arthritis
Topical skin therapy has no effect on the arthritis. Treatment options include anti-inflammatories (NSAIDs), Disease Modifying Drugs (sulphasalazine, methotrexate, cyclosporin) and steroid injections into joints or around tendons.
Surgical options are similar to those described for rheumatoid arthritis, in particular, fusion of the end finger joint with a screw is easily performed under local anaesthetic.