Increasing prevalence of allergic disorders has focused attention on primary prevention. There is a need to improve the accuracy of early-life predictors of atopy so that the at-risk population can be accurately defined and preventive measures instituted.
The predictive capacity of elevated cord IgE, with or without family history of atopy, to allergic symptoms and skin prick test (SPT) sensitization is evaluated in a birth cohort followed up prospectively for 4 years.
A birth cohort of 1456 consecutively born children was recruited in 1989. Data were collected on family history of atopy and cord serum total IgE (cord IgE) was measured. Of these, 1218 children were seen in the clinic at 4 years to determine the development of symptoms and signs of allergic disease and 981 were skin tested to a range of common food and aeroallergens.
Of 1218 children reviewed at age 4 years, 218 (17.8%) had symptoms of respiratory allergy and, of those skin tested (n = 981), 192 (19.6%) reacted positively. Twice as many children with elevated cord IgE (≥ 0.5 kU/L) at birth became sensitized to aeroallergens by age 4 years (34.8% vs 17.3%, P < 0.001). Positive predictive value (PPV) of elevated cord IgE for the development of aeroallergen sensitization was better than that of family history of atopy (34.8 vs 22.6%). Combining paternal atopy with elevated cord IgE substantially increased the predictive capacity (PPV 77.8%). Cord IgE levels did not correlate with clinical asthma or rhinitis at age 4 years and PPV for allergic respiratory symptoms remained poor at all cutoffs.
Cord IgE is better than family history for predicting atopy as defined by allergen sensitization and this predictive value can be further increased by combining cord IgE with paternal atopy.