Factors associated with the course of egg allergy in children

Abstract

Background: The risk factors that affect persistence of egg allergy are under investigation. Objective: To investigate the factors associated with the course of egg allergy and anaphylaxis in children. Methods: Children who had been diagnosed as having an IgE-mediated egg allergy and followed up until 6 years of age were enrolled. IgE-mediated egg allergy was diagnosed by a positive skin prick test result, specific IgE (sIgE) level of 0.35 kU/L or greater, and clear-cut history of egg-related symptoms or positive challenge test results. Results: A total of 203 (56%) of 363 egg allergic children were followed up until 6 years of age. Egg allergy resolved in 92 children (45%) at 2 years of age, 134 children (66%) at 4 years of age, and 145 children (71%) at 6 years of age. The resolution of egg allergy was associated with baseline egg sIgE level of 6.2 kU/L or less and the absence of anaphylaxis (hazard ratio, 0.32; 95% CI, 0.21-0.49; P < .001; and hazard ratio, 0.38; 95% CI, 0.21-0.69; P = .001, respectively). Baseline factors, including cut-off level of egg sIgE level greater than 6.2 kU/L, egg sIgE level, gastrointestinal symptoms after egg exposure, anaphylaxis with egg, and concomitant cow's milk allergy, were significantly associated with later resolution of egg allergy. The multivariate logistic regression determined that the natural logarithm for egg-white sIgE (odds ratio, 1.44; 95% CI, 1.09-1.91; P = .01) and the baseline gastrointestinal symptoms with egg (odds ratio, 6.86; 95% CI, 2.93-16.06; P < .001) were significantly related to a higher risk of anaphylaxis with egg. Conclusion: Baseline egg white sIgE levels, baseline gastrointestinal system involvement, concomitant cow's milk allergy, and anaphylaxis with egg may predict a more severe course of egg allergy with late resolution. Moreover, egg white sIgE levels and gastrointestinal symptoms after egg exposure seem to increase the risk of anaphylaxis with egg.