Long-Term Outcome of IgE-Mediated Cow’s Milk Allergy and Risk Factors for Persistence

Many children with immunoglobulin E–mediated cow’s milk allergy (IgE-CMA) have spontaneous resolution. Previous prospective studies have reported spontaneous resolution rates of 53% to 57% by the age of 5 years. The current extension study sought to evaluate resolution rates of IgE-CMA through the end of adolescence.From a cohort of 13 019 Israeli infants observed from birth, 54 had IgE-CMA confirmed by an oral food challenge (OFC). Persistence of IgE-CMA at 5 years was diagnosed in 23 children via a positive OFC or a recent objective allergic reaction to milk. IgE-CMA status was reassessed at age 17 in these 23 patients.Patients were evaluated at 17 years by questionnaire. Resolution was determined by regular milk consumption without adverse reaction or a negative OFC. Persistence of allergy was defined by a recent objective reaction to milk and a positive skin test greater than or equal to 8 mm or by sensitization with milk serum–specific IgE testing greater than 15 kUA/L.Of the 23 patients with persistence of IgE-CMA at 5 years, 8 (35%) had spontaneous resolution of IgE-CMA between the ages of 5 and 17 years. Overall, 39 of the 54 patients (72.2%) initially diagnosed with IgE-CMA had spontaneous resolution by 17 years. Risk factors for persistence of IgE-CMA at 17 years included skin prick test greater than 6 mm at the time of diagnosis, no cow’s milk feeding in infancy, and wheezing on diagnostic OFC or in association with a clinical adverse reaction to milk. Seven patients experienced objective adverse reactions after 5 years. Associations in these patients included wheezing or anaphylaxis on diagnostic OFC or initial reaction and current asthma.Spontaneous resolution of IgE-CMA occurs beyond 5 years. Few patients with IgE-CMA experience objective adverse reactions by late adolescence. Respiratory symptoms with early milk ingestion and asthma in adolescence were associated with persistence of IgE-CMA and of being at risk for more severe adverse reactions to milk until adolescence.The results of this population-based natural history study are interesting and may inform education and intervention strategies. The authors note the small study size, population limited to Israeli patients, and limited follow-up between the ages of 5 and 17 years for some patients as potential limitations of the current study. The authors pose an interesting query about the timeline for achievement of resolution between the ages of 5 and 17 years. This is an area for potential future study.