These findings solidify the involvement of IL-4/IL-13 cytokine signaling in epidermal barrier lipid abnormalities in AD skin through multiple mechanisms and suggest that patients receiving therapies targeting IL-4/IL-13 axis not only benefit by dampening the immune response but also by reversing the dysfunctional barrier through increasing epidermal lipid lengths, their total levels, and by increasing the expression of genes involved in forming the cornified envelope. Here, IL4 is linked to Alzheimer disease.