Difficult to treat psoriatic arthritis - how should we manage?

Psoriatic arthritis (PsA) is a chronic, multi-domain immune-mediated inflammatory arthritis with a high disease burden. PsA patients have significant co-morbidities like obesity, depression, fibromyalgia which can impact disease activity assessment. The management of PsA has undergone a paradigm shift over the last decade due to the availability of multiple biologic and targeted synthetic disease modifying anti-rheumatic drugs. Despite the availability of multiple therapeutic agents, it is not uncommon to find patients not responding adequately and continuing to have active disease and/or high disease burden. In our review, we propose what is "difficult to treat PsA", discuss differential diagnosis, commonly overlooked factors, co-morbidities that affect treatment responses, and suggest a stepwise algorithm to manage these patients.