Type 2 immunity, characterized by the production of T helper 2 (Th2)-related cytokines (e.g., IL-4 and IL-13) and the activation of eosinophil/mast cells [8], contributes to AD pathogenesis by impairing the epidermal barrier and causing symptoms such as inflammation and itch [5–7, 9–11]. Here, IL4 is linked to Alzheimer disease.