Are age-specific high serum IgE levels associated with worse symptomatology in children with atopic dermatitis?

Background Atopic dermatitis (AD) is a distressing disease associated with excoriations, pruritus, sleep disturbance, and elevation of serum total immunoglobulin E (IgE) levels. Objective To evaluate whether serum IgE levels correlate with the symptomatology and plasma chemokine levels in children with AD. Methods AD patients aged younger than 18 years were recruited from the pediatric dermatology clinic of a university teaching hospital, and the AD severity was evaluated using the SCORing Atopic Dermatitis (SCORAD) index. Concentrations of serum total IgE, eosinophil count, and plasma AD-associated chemokines [cutaneous T-cell-attracting cytokine (CTACK), thymus and activation-regulated chemokine (TARC)] were measured. Results One hundred and seventeen Chinese children with AD (64 boys and 53 girls), with an age (mean +/- standard deviation) of 10.7 +/- 4.4 years, were recruited. Their overall SCORAD index (mean +/- standard deviation) was 51.1 +/- 22.8. The total serum IgE level divided by the age-specific upper limit (AE) correlated well with the extent and intensity of AD, except for oozing/crusting, which was significant only in males. There was a significant correlation between AE and pruritus or sleep loss only in females. Levels of IgE, CTACK, and TARC, and eosinophil count, differed significantly between patients with mild, moderate, and severe disease. AE correlated well with TARC (r = 0.50, P < 0.001) and eosinophil count (r = 0.41, P < 0.001), but not with CTACK (r = 0.11, P = 0.270). The prediction of moderate to severe eczema by AE gave an area under the receiver-operating characteristic curve of 0.76 (95% confidence interval, 0.65-0.86; P = 0.004). An optimum positive predictive value of 94.2% was achieved with a cut-off point of AE of 2.95, sensitivity of 75.0%, and specificity of 66.7%. Conclusion AE correlates significantly with various objective clinical scores and chemokine markers of AD, and is a useful indicator for predicting moderate to severe AD in children.