Agreement between the Skin Prick Test and Specific Serum IgE for Egg White and Cow's Milk Allergens in Young Infant with Atopic Dermatitis

Background: The skin prick test (SPT) for detecting atopic sensitization is not preferred in young infants with atopic dermatitis (AD) because of concerns about poor skin reactivity. This study aimed to evaluate whether the results of SPT agreed well with those of specific serum immunoglobulin E (sIgE) antibody test in young infants with AD. Methods: This study included 2,077 eligible infants (age, <12 months) with AD who were tested by either SPT or sIgE between 2007 and 2011. Among them, 199 infants tested for egg white (EW) and 192 infants tested for cow's milk (CM), by both SPT and sIgE on the same day were identified and reviewed retrospectively. Kappa statistics and tests for equal kappa statistics were used to evaluate the agreement between the SPT and sIgE. Results: The mean wheal diameter and the allergen-to-histamine ratio of SPT showed substantial agreement with those of sIgE for EW (kappa = 0.62, 0.69) and CM (kappa = 0.34, 0.47). The agreement for EW was significantly higher <6-month-old than in >= 6-month-old infants (kappa = 0.79 vs. 0.54, P = 0.02), and that for CM was similar (P = 0.60). The mean wheal diameters for EW and CM were evenly distributed, and did not show increasing trends regardless of age in months (P-trend = 0.13 and 0.06, respectively). Conclusions: The results of SPT agreed well with those of sIgE. This finding provides a rationale for using SPT, and suggests that SPT can be used along with sIgE to detect food sensitization in young infants with AD.