There are currently no reliable biomarkers that can differentiative atopic dermatitis (AD) from other conditions. “An elevated total and/or allergen-specific serum IgE level” is a common associated laboratory feature, however it is not present in about 20% of people with AD. Therefore, levels remain controversial to use as any kind of predictor of AD and/or determining severity level.
Read more about biomarkers recommendations at the American Academy of Dermatology.