The present invention relates to a composition or a method for preventing or treating skin disease, and more specifically, to a composition or a method for preventing or treating allergic or inflammatory skin disease, the composition comprising N-acetyl Leukotriene E4 (N-acetyl-LTE4) or a pharmaceutically acceptable salt as an effective ingredient. The N-acetyl LTE4 alleviates itching, caused by various causes, by suppressing the generation of water-soluble cytokine, in particular, IL-2 and IL-17, and at the same time has an immunomodulatory effect. Thus, the present invention can be variously used as a composition for alleviating itching induced by histamine, chloroquine, contact dermatitis, or the like, an agent for preventing or treating allergic or inflammatory skin disease including atopic dermatitis, and the like.