IL17A and psoriatic arthritis: The recent introduction of systemic biologic drugs (TNF-α inhibitors, the anti-IL12/23 ustekinumab, the IL-17/IL-17 receptor antagonists, and the anti-IL-23 agents) alongside chemically synthesized medications (JAK inhibitors) has revolutionized the treatment of psoriasis and psoriatic arthritis, offering more targeted therapeutic options.