Diagnosing Psoriatic Arthritis Diagnosing psoriatic arthritis can be complex. However everyone affected one or more of joint, tendon or spine inflammation. Most of the time patients have, or have had, psoriasis of the skin or nail. In This VideoAna-Maria Orbai, MD, MHSDr. Orbai is an Assistant Professor of Medicine and Director of the Psoriatic Arthritis Program in the Division of Rheumatology.