The aim of our study was to determine the prevalence of psoriatic arthritis in the patients with psoriasis and to analyze retrospectively the results of a 34-year multidisciplinary management of the patients with psoriatic arthritis. The study included 162 out of 183 treated patients with psoriatic arthritis, aged 48 +/- 15 years. All the patients satisfied the current diagnostic criteria for psoriasis and psoriatic arthritis according to the American College of Rheumatology. Psoriatic arthritis developed in 183 (9.3%) out of 1976 patients with psoriasis. Time interval for establishing the diagnosis was 4 years. A positive family history of the disease had 15.0% of the studied patients. Its onset was most often at 42 years of age in 70.4% of the cases, and 2 months to 59 years after the appearance of psoriasis. Psoriatic arthritis without psoriasis appeared in 1.8% of the patients. A severe form of arthritis had 64.2% of the patients, mainly the patients with scalp psoriasis (chi2 = 3.2; p < 0.05). Nail changes had 35% of the patients. Distal interphalangeal joints were involved in 63.6%, axial skeleton in 36.4%, oligoarthritis in 45.0%, polyarthritis in 55.0%, and mutilating form in 6.8% of the patients. Elevated Erythrocyte Sedimentation Rate was reveald in 61.7% of the patients. Immunoglobulin M (IgM) rheumatoid factor was altered in 4.3% of the patients. The human leukocyte antigen (HLA) typing in the 28 patients were: A2 32.0%, A3 18.0%, Al and A9 14.0%, A28 and A29 3.5%, B8 and B16 14.0%, B5 and B12 11.0%, B13, B15, B18, B27 and B35 7.0%. Radiologic changes were most often in hand and foot joints, less frequently in the knees and quite infrequently in hips and shoulders joints. Sacroiliitis was found in 46.4% of the patients. Psoriasis was treated with topical corticosteroids and salicylic ointments in all the patients, ultraviolet (PUVA therapy) in 5.6% and retinoids in 4.3% of them. Artrithis was treated with nonsteroidal anti-inflammatory drugs, with systemic corticosteroids 41.3% and with disease modified antirheumatic drugs, most frequently methotrexate, 59.9% of the patients. Radionuclide synovectomy was performed in 6.8%, surgery in 6.2% and physical therapy in all the patients. Psoriatic arthritis developed in 9.3% of the psoriatic patients. Time interval for establishing the diagnosis was long, and there were no specific laboratory findings. All the synovial joints could be involved in the psoriatic process. Scintigraphy should be used only in case of early suspected sacroiliitis. The treatment of psoriatic arthritis was the teamwork between the dermatologist, rheumatologist, physiatrist and orthopedic surgeon.