I just wanted to say best of luck and your aunt is lucky to have you. There are several treatments that can help manage the disease, it is a matter of finding what works best for your Aunt. Find a Reumatologist she trusts and go from there.
What medication is your aunt taking for it? Here are some basics about it. PsA is a form of arthritis that afflicts people with psoriasis. Not all psoriasis patients will develop it. Some patients get the arthritis first but usually the lesions show up first. Symptoms are usually painful swollen warm joints. Even within PsA, there are several different types that a person can develop. These types are identified by where the arthritis appears; one side of the body, both sides of the body, in the hands, in the spine or a destructive form that effects the small bones in the hands. There is no cure for PsA but there are medications to manage the symptoms. Medications used to treat this condition include anti-inflammatories or NSAIDs, steroids, DMARDs (disease modifying drugs, immunosuppressants and TNF alpha blockers.