TRPA1 and Alzheimer disease: Treatment of mouse skin with 2,4-dinitrochlorobenzene (DNCB), for example, activates TRPA1 and generates an AD-like phenotype [82], and mice lacking TRPA1 have decreased dermatitis and pruritus scores, Th2 cytokines, epidermal hyperplasia, ear thickness, mast cell and macrophage infiltration [83].