Atopic dermatitis is diagnosed with pruritus as a necessary symptom, plus 2 or more of the following 4 indicators: onset before age 2; history of generalized dry skin with flexural skin involvement (including elbow fossa, N fossa, anterior ankle or peri-neck); history of asthma and/or allergic rhinitis, or history of allergic disease in first-degree relatives. 2, laboratory tests for atopic dermatitis Most patients have elevated total serum IgE, increased peripheral blood eosinophils, allergy to a variety of allergens, and cellular immune function may be low.