Predicting outgrowth of IgE-mediated cow's milk allergy: Diagnostic tests in children under two years of age.

BACKGROUND

Limited studies conducted on children <2 years old and/or involving a skin prick test (SPT) for fresh milk (FM) have examined the predictive value of allergometric tests for outgrowth of cow's milk allergy (CMA). We investigated the optimal decision points for outgrowth (ODP) with SPT for commercial cow's milk extract (CE) and FM and specific immunoglobulin E (sIgE) levels for milk proteins to predict outgrowing allergy in children <2 years old.

METHODS

SPTs for CE and FM, tests for sIgEs (cow's milk, casein, α-lactoalbumin, β-lactoglobulin) and oral food challenges (OFC) were performed in children referred for evaluation of suspected CMA, and 15 months after diagnosis.

RESULTS

Fifty-one children (median age, 7.5 months; range, 2-23 months) were enrolled. Five had a history of anaphylaxis and 26 of 48 children with a positive initial challenge underwent milk elimination. The last OFC was performed in 28 children of whom 13 reacted to milk. The initial SPT responses to CE and FM and milk sIgE levels of the patients with persistent CMA were higher at diagnosis, with ODP of 7mm, 9mm, and 10.5kU/L, respectively; these values remained higher with ODP of 4mm, 11mm, and 10.5kU/L at the last OFC.

CONCLUSION

Higher initial SPTs for FM and CE and higher initial sIgE levels for cow's milk proteins are associated with a reduced likelihood of outgrowth. Initial milk sIgE level <10.5kU/L and initial SPT for fresh milk <9mm are related to the acquisition of tolerance in the follow-up period.