PURPOSE OF THE STUDY.
Previous studies on the natural history of milk allergy have been limited in duration and in geographic area. Through this multisite, longitudinal study, the authors provide a natural history of milk allergy and identify means for early prediction of likelihood of resolution.
Children aged 3 to 15 months were recruited from 5 food allergy referral centers, using the following inclusion criteria: history of immediate allergic reaction to cow’s milk or egg with positive skin-prick test (SPT) to the inciting food; or moderate-to-severe atopic dermatitis (AD) with positive SPT to either milk or egg.
The children in this cohort with milk allergy, diagnosed either at time of enrollment or during the study, were followed over time. At enrollment, investigators assessed baseline characteristics (more detail in the next section). Participants were again assessed at 6 months and yearly thereafter, with more frequent follow-up as needed. Resolution of milk allergy was established by ingestion of whole uncooked milk products without reaction. Analyses were performed to assess the effect of various baseline characteristics on likelihood of resolution of milk allergy.
Of 293 children in the cohort diagnosed with milk allergy, 154 (53%) participants experienced resolution of milk allergy at a median age of ∼5.3 years and a median age at last follow-up of 5.5 years. Baseline characteristics most predictive of milk allergy resolution, all with P values <.001, were milk-specific immunoglobulin (Ig)E (<2 vs ≥10 kUA/L with hazard ratio 5.7), SPT wheal size (<5 vs >10 mm with hazard ratio 3.7), and severity of AD (mild/none versus moderate/severe with hazard ratio 2.09). The authors use these 3 baseline characteristics to calculate a composite score for prediction of an individual patient’s likelihood of milk allergy resolution. Baseline characteristics that were not significant predictors of resolution included milk-specific IgG4, milk-specific IgE/IgG4 ratios, and casein-stimulated T-cell studies.
This longitudinal, multisite prospective cohort study provides a natural history of food allergy over a follow-up period of ∼5 years. Approximately 50% of children with milk allergy will experience resolution by 5 years of age. Milk-specific IgE, SPT wheal size, and AD severity at baseline are significant predictors of likelihood of resolution.
The exceptional follow-up rate supports the validity of the findings, the large size of the cohort and use of multiple sites strengthen its generalizability, and the length of follow-up and identification of significant predictors of milk allergy resolution highlight the utility of the study. Additional investigation may more rigorously identify age at resolution through food challenges at regular intervals and may focus on identifying additional modifiers in resolution of milk allergy, particularly ingestion of baked milk products at the start of and during the study period.
- Copyright © 2013 by the American Academy of Pediatrics