[Arthritis psoriatica].

The symptoms ofpsoriatic arthritis vary from arthralgia and enthesitis to chronic erosive and mutilating arthritis, and are seen in 6-39% of all psoriasis patients. Because of increasing awareness of the clinical signs of psoriatic arthritis among both dermatologists and rheumatologists, the diagnosis ofpsoriatic arthritis is made more often; this is important since earlier diagnosis and treatment can avoid irreversible joint destruction. The overlap between the immunological mechanisms in the pathogenesis ofpsoriasis and psoriatic arthritis has led to the identification of common therapeutic targets, of which tumour-necrosis factor (TNF) is the most important. The successful treatment of psoriasis patients with TNF-a-blocking agents has not only brought about a marked improvement in the quality of life of many patients but has also improved the insight into the pathogenesis, for example by demonstrating that the role of acquired immunity is much more important than was previously thought. The Dutch Society of Dermatology and Venereology and the Dutch Society of Rheumatology have drawn up guidelines for the treatment of patients with psoriasis and psoriatic arthritis using these so-called biologics.