The incidence of arthritis in psoriatics is probably five times that of the normal population.
Classical psoriatic arthritis involves the digits of an affected finger, where there is a sausage like swelling of the affected digit. Digital arthritis is particularly common in chronic pustular psoriasis of the fingertips, acrodermatitis continua of Hallopeau.
Patients may also have a rheumatoid-like arthritis with a negative rheumatoid factor. Psoriatics can also develop an axial arthritis, psoriatic spondylitis.
In addition, there are many other variants of arthritis found in psoriatics.
- Arthritis associated with psoriasis responds well to oral methotrexate 2.5-5 mg q12h x 3 once a week. This treatment regimen treats both the psoriasis and the psoriatic arthritis.