The Natural Course of Immediate-Type Cow’s Milk and Egg Allergies in Children

BACKGROUND: Most of children with cow's milk (CM) and hen's egg allergies are known to outgrow their diseases with time, but recent studies have demonstrated that children tend to continue to have allergic symptoms in adolescence and adulthood. The aim of this study was to investigate the natural course of CM and egg allergies in Korean children and analyze prognostic factors. METHODS: In this retrospective study, we reviewed data of children with CM allergy and with egg allergy using medical records and parental telephone interviews. Diagnosis of CM or egg allergy was based on positive oral food challenge test or convincing history of allergic symptoms in combination with positive allergen-specific IgE. Acquisition of tolerance was defined by the absence of allergic symptoms after reintroduction of the offending foods. RESULTS: Half of the children outgrew CM allergy at a median age of 8.7 years. CM-specific IgE level at the first reaction was a significant prognostic factor for oral tolerance in CM allergy (p < 0.05). The median age to acquire oral tolerance in 50% of patients with egg allergy was 5.6 years. Egg-specific IgE level at the first reaction and family history of allergic diseases significantly affected the prognosis in children with egg allergy (p < 0.05). CONCLUSIONS: Half of Korean children with CM and egg allergies had symptom resolution at 8.7 and 5.6 years of age, respectively. Our results also suggest that CM- and egg-specific IgE levels at the first reaction are the most significant prognostic factors in predicting acquisition of oral tolerance.