While the underlying events and key factors involved in the development and progression of AD are the subject of ongoing debate, there are at least two major and converging abnormalities in the epidermis structure due to i.e., reduced expression of filaggrin (FLG) and IgE-mediated sensitization to food and environmental allergens (Roesner and Werfel 2019; Langan et al. 2020). Here, FLG is linked to Alzheimer disease.