AD can be classified into two major endotypes based on both symptoms and pathogenesis: the more common “extrinsic” (high serum IgE levels, eosinophilia, atopic background, greater filaggrin (FLG) mutation rate) and the rarer “intrinsic” (normal serum IgE level, delayed onset, female predominance, more preserved barrier function, increased prevalence of metal contact hypersensitivity, lack of other atopic background) types. The gene discussed is IGHE; the disease is Increased total eosinophil count.