Prevalence Clinical Syndromes and Outcomes of Cow's Milk Allergy in Children: A Four-Year Follow-Up

Background/Objectives: Cow's milk allergy (CMA) manifests with various clinical syndromes and has a wide range of symptoms in infants. This study aims to investigate the prevalence, clinical presentation, and outcome of clinical types and subtypes of CMA diagnosed in children within the first 12 months of life. Methods: Children with a CMA diagnosis were included in this mixed retrospective and prospective cohort study and were followed up for four years. Data recorded included clinical manifestations, feeding modes, and outcomes. Follow-up included oral cow's milk (CM) challenge and/or elimination-reintroduction of CM, provided there was parental consent. Also, skin prick test and serum CM-specific IgE were assessed when needed. Results: A total of 93 infants (age: 3 days to 24 months) diagnosed with CMA were included. Prevalence was 28% for IgE-mediated CMA and 72%, 49.5%, 18.3%, and 3.7% for non-IgE-mediated CMA and its subtypes, Allergic Proctocolitis (AP), Food Protein induced Enteropathy (FPE), and Food Protein Induced Enterocolitis Syndrome (FPIES), respectively. Main manifestations were gastrointestinal (74%), skin rash (31%), failure to thrive (11.8%), feeding aversion (15.1%), respiratory symptoms (5.4%), and irritability/restlessness (9.7%). Follow-up revealed a high rate of AP and FPE tolerance within the first year, while FPIES and IgE-mediated CMA achieved tolerance at an older age. Conclusions: Our study demonstrated the predominance of AP and increased incidence of gastrointestinal involvement. Outcome was good for AP and FPE but less favorable for FPIES and IgE-mediated CMA. Our results, combined with published data, could increase our understanding of CMA-associated syndromes in infants and contribute to the guidance of effective management.