Psoriasis is a common chronic skin condition that is prevalent worldwide. Despite the numerous treatment options available, discrepancies exist between international guidelines. Areas covered: This review aims to evaluate the current international guidelines for the systemic treatment of psoriasis and psoriatic arthritis. Expert commentary: Most guidelines are unanimous on medication dosing and laboratory monitoring. However, even the most up-to-date guidelines do not include many of the new biologic medications. Guidelines will require frequent updates to include the newer treatments and will soon need to state a recommendation on the use of biosimilars.