IGHE and allergic disease: Clinical phenotypic variability in AD may include time of disease onset (infancy, adolescence, adulthood), likelihood of persistence into adulthood, severity (mild-moderate, severe), co-existence of other allergic disease, co-existence of mendelian disorders associated with AD (e.g., Netherton's syndrome), IgE-mediated food or aeroallergen sensitization, presence of Staphylococcus aureus colonization and presence or absence of viral infections (e.g., eczema herpeticum) (22, 26).