A German retrospective study of 103 consecutive infants and children (aged 3 months to 17 years) with atopic dermatitis (AD) attempted to use total serum IgE levels to differentiate intrinsic AD (ADi) from extrinsic AD (ADe).There were 65 ADe patients and 38 ADi patients in the sample. Associations of allergen-specific IgE (asIgE) status with atopic co-morbidity (asthma, allergic rhinitis, food allergy) were statistically significant (P = 0.0035, P = 0.0106 and P = 0.0004, respectively). A cut-off total IgE level of 106 kU/mL had positive and negative predictive values of 93.6% and 64.3%, respectively. Clinical decision points predictive of positive asIgE results were identified in 90%, 95% and 99% of patients ...