Psoriasis is a multifactorial recalcitrant inflammatory skin disease characterized by bothersome scaly reddish plaques especially on frequently chafed body parts, such as the extensor sites of the extremities and scalp. Nonetheless, through recent advance in molecular-targeted therapies including biologics and small-molecule inhibitors, even the severest symptoms of psoriasis and its comorbidities, such as psoriatic arthritis, can be excellently treated. The superb clinical effects lead to not only remarkable alleviation of symptoms but also a deep understanding of patients' impaired "quality of life" caused by this disease. Along with the development of novel treatment options targeting various specific molecules, such as proinflammatory cytokines and signal transduction-associated molecules, clinicians have thoroughly understood the molecular mechanism of psoriasis, and discovered that the IL-23/IL-17 axis mainly depending on Th17 cell function is a crucial pathogenesis of this disease. Accumulation of knowledge about the working mechanism and clinical effect of molecular-targeted therapies is indispensable for clinicians to establish a more refined therapeutic strategy for treating psoriasis.
Keywords: IL-17; IL-23; IL-36; JAK; PDE4; RORγT; TNF; biologics; cytokines; molecular mechanism; psoriasis; psoriatic arthritis; small-molecule inhibitors.
© 2021 Japanese Dermatological Association.