Evaluation of the natural course and effective factors in egg allergy

Abstract

Egg allergy (EA) is one of the most common food allergies in early childhood, often resolving spontaneously over time. However, the course of the disease varies among individuals, and several factors have been proposed to influence its persistence. This study aimed to evaluate the clinical and laboratory features of children diagnosed with EA, assess the frequency and timing of tolerance development, and identify risk factors associated with persistent allergy. Material and Methods: A retrospective review was conducted on children diagnosed with EA and followed for at least six months between June 2010 and June 2016. Demographic characteristics, clinical manifestations, laboratory parameters, skin prick test (SPT) results, and coexisting atopic conditions were recorded. Patients were classified as either tolerant or persistent based on follow-up oral food challenge results and clinical history. Results: Among the 173 patients diagnosed with egg allergy, 83.2% (n=144) developed tolerance, while 16.8% (n=29) had persistent allergy. Tolerance was observed in 61% (n=105) by age 3, 73% (n=126) by age 4, and 79% (n=136) by age 5. Patients with persistent EA had significantly higher egg-specific IgE levels at both admission (5.34 kU/L [0.42–3.74] vs. 1.27 kU/L [0.42–3.74], p=0.002) and final control (8.56 kU/L [1.18–40.4] vs. 0.96 kU/L [0.29–3.30], p<0.001), as well as larger wheal diameters in SPTs with raw egg at admission (9 mm [6–14] vs. 6 mm [5–9], p=0.008) compared to those who developed tolerance. The presence of nut allergy (persistent: 6/27, 22.2% vs. tolerant: 8/141, 5.7%; p=0.004) and legume allergy (persistent: 5/27, 18.5% vs. tolerant: 9/141, 6.4%; p=0.037) was also significantly associated with persistence. Conclusion: Higher initial and sustained egg-specific IgE levels, larger SPT responses, and concomitant nut and legume allergies are potential risk factors for the persistence of EA. Additionally, the younger age of tolerance development observed in this cohort compared to previous studies may reflect population-specific differences in allergy phenotype.