Although treatment of moderate-to-severe AD has entered a new era centered on biologic agents, interindividual differences in the expression of key neuroimmune genes such as IL-31, MRGPRX2, TRPA1, NGF, and CGRP contribute to molecular heterogeneity that is closely associated with the intensity of pruritus and disease chronicity, and these differences significantly affect patients’ responses to therapy (187). This evidence concerns the gene IL31 and Alzheimer disease.