Testing the cow’s milk-related symptom score (CoMiss™) for the response to a cow’s milk-free diet in infants: A prospective study

The diagnosis of cow’s milk allergy (CMA) is particularly challenging in infants, especially with non-Immunoglobulin E (IgE)-mediated manifestations, and inaccurate diagnosis may lead to unnecessary dietary restrictions. The aim of this study was to assess the accuracy of the cow’s milk-related symptom score (CoMiSS™) in response to a cow’s milk-free diet (CMFD). We prospectively recruited 47 infants (median age three months) who had been placed on a CMFD due to persisting unexplained gastrointestinal symptoms. We compared data with 94 healthy controls (median age three months). The CoMiSS™ score was completed at recruitment and while on the exclusion diet. In 19/47 (40%) cases a response to the diet occurred. At recruitment CoMiSS™ was significantly higher in cases compared to controls (median score 8 vs. 3; p-value: <0.05), 9 cases had a score ≥12 and 8/9 normalized on CMFD. An oral milk challenge was performed in all 19 responders and six of these had a positive reaction to cow’s milk (CM). In eight infants IgE allergy tests were positive. The receiver operation characteristic (ROC) curve identified a CoMISS™ score of 9 to be the best cut-off value (84% sensitivity, 85% specificity, 80% positive (PPV) and 88% negative predictive value (NPV)) for the response to CMFD. We found CoMiSS™ to be a useful tool to help identify infants with persisting gastrointestinal symptoms and suspected CMA that would benefit from CMFD.