Factors effecting natural course of egg allergy

Background. There is limited data about the natural course of egg allergy in the literature. We aimed to analyze the factors that can affect the tolerance or persistence of egg allergy. Methods. A total number of 126 IgE- mediated egg allergic patient who had data about tolerance gaining were included in the study. Demographic and laboratory data were recorded retrospectively. Kaplan-Meier curves was used for estimation of resolution and the factors related to resolution by Cox regression model. Results. Among 126 patients 81 (64.2%) had gained tolerance with a median survival time of 48 months (min 12- max 121). Tolerance was gained in 22.2% (28) of these patients in the first 2 years, in 46.8% (49) 2-6 years, 3.1% (4) between 7-12 years. In univariate analysis, no history of anaphylaxis (at initiation or during OFC) (Hazard ratio 2.193; 95%CI 1.309-3.674, p = 0.003), baseline sIgE level less than 8.2 (Hazard ratio 11.292; 95%CI 2.766-46.090, p = 0.001) and baseline egg SPT less than 11 mm (Hazard ratio 2.906; 95%CI 1.424-5.930, p = 0.003) were found to be related to earlier resolution of egg allergy. In multivariate analysis only anaphylaxis was significantly related to later resolution (Hazard ratio: 6.547; 95%CI 15.80-27.434, p = 0.01). Conclusions. Higher levels of egg sIgE, skin prick test induration and anaphylaxis at onset or during oral food challenge, can give hint about persistence of egg allergy.