JAK-inhibitors in dermatology - small molecules, big impact? Overview of the mechanism of action, previous study results and potential adverse effects.

Numerous chronic inflammatory skin diseases are associated with the release of proinflammatory cytokines, which act via the intracellular JAK-STAT pathway. JAK inhibitors represent a promising, targeted therapeutic approach for cutaneous diseases. Impressive effects have been achieved with these agents in recent years. With the approval of the JAK-inhibitors Baricitinib, Upadacitinib and Abrocitinib, new systemic therapeutic agents are now available for moderate to severe atopic dermatitis. Other diseases in which the effectiveness of these small molecules could be shown are psoriasis, chilblain lupus, dermatomyositis, vitiligo and alopecia areata. As dermatologists, we are facing a whole series of new drug approvals. In this minireview we explain the active principles of JAK inhibitors and review study results in selected inflammatory skin diseases. Finally, possible side effects and initial as well as follow-up laboratory examinations for these drugs are discussed.