Prevalence of Sonographic Abnormalities of Joints and Entheses in Psoriasis Patients With or Without Musculoskeletal Complains

The objectives of this study are: * to estimate the prevalence and severity of inflammatory (synovitis, tenosynovitis, enthesitis, dactylitis) and structural (erosions, osteophytes, enthesophytes, cortical irregularities ) ultrasound lesions in psoriasis patients with or without related musculoskeletal symptoms; * to compare them to healthy subjects or patients suffering from rheumatoid arthritis and osteoarthritis.