This review has allowed us to find out that there are conflicting and controversial data for leptin in this skin disease, mainly due to both the small cohort size analysed in some studies and the classification of AD in different groups (severity, phenotype, age, race, or gender) as well as other parameters including (but not limited to) the type of corticosteroid used, IgE levels, BMI, or cytokine production. The gene discussed is IGHE; the disease is Alzheimer disease.