Cytokines are the extracellular signals which exert distinct effects in target cells. The JAK-STAT cascade is a signaling pathway that transmits signals from cell membrane receptors to the nucleus. This messenger system plays an important role in various dermatological diseases. The cytokine receptor on the cell surface recruits JAKs upon cytokine binding. Subsequently, STATs get phosphorylated, move into the nucleus, and attach to distinct DNA sequences. Thus, cytokine-induced gene transcription is initiated.