In this study, PEW reduces the infiltration of mast cells in the skin of DNCB-induced AD mice and downregulates the levels of serum IgE and histamine [Figures 3A(b), D; Figure 4], suggesting that PEW ameliorates AD-like symptoms in mice partly by affecting the IgE-mast-cell axis. This evidence concerns the gene IGHE and Alzheimer disease.