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

Background: Resolution rates of IgE-mediated cow's milk allergy (IgE-CMA) by age 5 years and risk factors for its persistence were previously described. Objective: To extend follow-up until the end of adolescence. Methods: This is an extension study of 23 of 54 patients diagnosed with IgE-CMA from a population-based study of 13,019 newborns, who remained allergic at age 5 years. Patients were examined at age 17 years, and their history was reviewed. Resolution was determined by regular milk consumption without adverse reactions or a negative oral food challenge (OFC). Allergy was defined by a recent objective reaction to milk and a positive skin prick test (SPT), or by sensitization >= 95% positive predictive value (PPV) to milk. Risk factors for persistence at age 17 years were examined in the entire cohort. Results: Of the 23 patients followed, 8 (35%) had spontaneous resolution and 15 had persistent IgE-CMA. Overall, 39 of the 54 patients (72.2%) initially diagnosed with IgE-CMA had spontaneous resolution by age 17 years. Risk factors for IgE-CMA persistence at age 17 years included SPT >6 mm at the time of diagnosis (P = .03), no cow's milk formula feeding in the nursery (P = .008), and wheezing on diagnostic OFC/initial reaction to milk (P = .04). Seven patients experienced objective reactions after age 5 years. These patients had more wheezing (P = .045) or anaphylaxis (P = .02) on diagnostic OFC/initial reaction and more current asthma (P = .007). Conclusions: Significant rate of spontaneous resolution of IgE-CMA still occurs beyond age 5 years, and few patients with IgE-CMA, mostly asthmatics, experience objective reactions by early adulthood. This should be considered in the treatment approach of patients with IgE-CMA. (c) 2024 American Academy of Allergy, Asthma & Immunology