It might be difficult to diagnose psoriatic arthritis because your symptoms may be mild early on making it hard to tell it apart from other types of arthritis. Also, your symptoms may be different from those of someone else with psoriatic arthritis. Your doctor will ask about your symptoms and examine your joints and may also ask about your medical history and consider other factors that may mean psoriatic arthritis is more likely, including if you developed psoriasis in the last few years and then a type of arthritis appeared, if you have stiffness in at least one joint and if a member of your family has psoriatic arthritis.
Attribution: BUPA