Cow's Milk Allergy in Breastfed Infants: What We Need to Know About Mechanisms, Management, and Maternal Role

Cow's milk allergy is one of the most prevalent food allergies in infancy. Exclusive breastfeeding is the recommended source of nutrition for the first six months of life, but some infants may develop cow's milk allergy due to the transfer of milk proteins such as β-lactoglobulin through breast milk. There are still many uncertainties about cow's milk allergy in breastfed babies. The purpose of this review is to summarize the latest findings mainly focused on immunological mechanisms and challenges in diagnosis. We pointed out which clinical signs in breastfed infants are associated with immediate IgE responses and which are linked to delayed non-IgE mechanisms or mixed IgE/non-IgE-mediated reactions. Since standard IgE tests are often useless in non-IgE cases, diagnosis typically involves dietary elimination and cow's milk challenge. This study addresses the controversial topic of maternal elimination diets, assessing the nutritional risks to both mothers and infants in relation to their possible benefits. It has also been discussed whether the microbiota signature could be a potential factor in both tolerance development and the risk of cow's milk allergy in early life. Overall, accurate diagnosis and personalized treatment plans are vital to prevent overdiagnosis and ensure proper growth while maintaining the practice of breastfeeding.