Dietary Restriction Efficiency Assessment in CMPA

Symptom Improvement Rate After Elimination Diet Approach (EDA)

The proportion of patients in each group who achieve significant symptom improvement at 2 weeks after starting the diagnostic EDA with different hypoallergenic formulas (amino acid formula \[AAF\] vs. extensively hydrolyzed formula \[eHF\]). Improvement Criteria (must meet at least one of the following for ≥3 consecutive days): * A ≥50% reduction in the Diarrhea and Blood Stool Score (baseline gastrointestinal-dominant symptoms). * A ≥50% reduction in the Cow's Milk-related Symptom Score (CoMiSS) total score. ③ Marked improvement or resolution of original gastrointestinal and/or skin symptoms (e.g., spit-up, vomiting, diarrhea, abdominal distension, abdominal pain, reflux, eczema) as assessed by the attending physician.

Time to Achieve Significant Symptom Improvement

The number of days from the start of the intervention (EDA) until the child first meets the predefined criteria for significant symptom improvement (as defined in the primary outcome). For children who do not achieve improvement within the study period, data will be censored at the last assessment.

Cow's Milk Protein Allergy (CMPA) Diagnosis Rate (Oral Food Challenge [OFC] Positivity Rate)

The proportion of children with positive EDA response who subsequently have a positive OFC, confirming CMPA diagnosis. Children who are directly diagnosed due to high-risk allergic reactions (without OFC) are also included in the numerator as positive cases.

Sensitivity and Validity of the CMPA Symptom Scoring System

Diagnostic performance (sensitivity, specificity) of the newly developed CMPA symptom scoring system (including CoMiSS, Diarrhea and Blood Stool Score, and Fask Score) compared against the OFC gold standard. The scoring system is used to differentiate CMPA-positive from CMPA-negative cases.