The utility of casein spt and IgE values in predicting anaphylaxis and reactivity to baked-milk.

Background: Most children with milk allergy can tolerate baked-milk; however, a small percent still react to it. Identifying indicators that might forecast potential reactions to baked goods is essential.

Objective: The aim of this study is to determine the predictive factors and some decision points for estimation of baked-milk reactivity and severe reactions.

Methods: A cross-sectional study was performed. Participants who were reactive to unheated-milk underwent an oral food challenge with baked milk. The reactive group was classified into anaphylactic and non-anaphylactic reaction categories. The immunoglobulin E and skin prick test levels of milk and its components were compared among these groups.

Results: The study was conducted with 110 patients. The median age of participants was 16 months (IQR:12-31). Baked-milk reactivity was observed in 41% (n:46/110) of patients. The optimal cut-off point for baked-milk reactivity was 4.68kIU/L for casein-sIgE (84% specificity, 75% sensitivity, AUC:0.827) and 7mm for casein-SPT (87.2% specificity, 51.1% sensitivity, AUC:0.721)(p<0.001, p<0.001). The positive decision point for anaphylaxis for casein-sIgE was 34kIU/L (95% specificity, 47.6% sensitivity, AUC 0.707). In the group younger than 24 months old, the cut-off values for casein-sIgE were found to be 5.4kIU/L (95% specificity, 66.6% sensitivity, AUC:0.844) and casein-SPT 7mm (91% specificity, 37% sensitivity, AUC:0.708)(p<0.001, p:0.002).

Conclusion: Our investigation revealed that the most accurate indicator for BM reactivity was casein-spIgE and SPT. While we established a threshold for severe reaction with BM in our study population, we consider that our findings require validation prior to therapeutic implementation.