NGHIỆM PHÁP THỬ THÁCH ĐƯỜNG MIỆNG Ở TRẺ MÀY ĐAY TIẾP XÚC VỚI SỮA BÒ

Abstract

Background: Contact urticaria to cow’s milk may indicate IgE-mediated cow’s milk allergy (CMA) but may also reflect isolated cutaneous sensitization. The diagnostic value of allergy tests in this subgroup therefore remains uncertain.

Methods: We conducted a retrospective descriptive case series at Children’s Hospital 1 from 2016 to 2025. The study assessed the relationship between skin prick test (SPT) results with fresh cow’s milk, cow’s milk–specific IgE levels, and oral food challenge (OFC) outcomes in children whose main or only manifestation was contact urticaria to cow’s milk.

Results: Thirteen children underwent OFC, with a median age of 9 months. SPT with fresh cow’s milk was positive in 2/13 children, and cow’s milk–specific IgE was positive in 4 of the 5 children tested. Among the 8 children undergoing OFC for diagnostic purposes, all had negative OFC results. Among the 5 children undergoing OFC to assess tolerance acquisition, 2 had positive results, both presenting with generalized urticaria after a 1 mL milk dose; both reactions were self-limited and required no treatment. The remaining 3 children had negative OFC results. Among children with negative OFC results, the median tolerated dose was 109 mL. Three children developed localized contact urticaria at doses of 5–10 mL, but these reactions did not progress to generalized or systemic symptoms with further dose escalation.

Conclusions: Children presenting with contact urticaria to cow’s milk may still tolerate oral ingestion despite positive allergy test results. OFC remains essential for confirming clinically relevant cow’s milk allergy (CMA) and for assessing tolerance, thereby helping to avoid unnecessary dietary elimination.