When Should Infants with Cow's Milk Protein Allergy Use an Amino Acid Formula? A Practical Guide.

Cow's milk protein allergy (CMPA) is the most common food allergy in childhood and its prevalence ranges between 1.9% and 4.9%. Most children present with CMPA at age less than 1 year and therefore may require a hypoallergenic formula in the absence of breast milk. Hypoallergenic formulas include both extensively hydrolyzed formula (EHF) and amino acid formula (AAF). For most children with a CMPA, an EHF will be sufficient for symptom resolution, as reflected in current guidelines, but there is a subset of children with CMPA where an AAF may be indicated. The appropriate use of an AAF is a highly debated topic, because there is a significant fiscal burden to either the health care system or the parents. From the literature, the following themes were identified as possible reasons for choosing an AAF: (1) symptoms not fully resolved on EHF, (2) faltering growth/failure to thrive, (3) multiple food eliminations, (4) severe complex gastrointestinal food allergies, (5) eosinophilic esophagitis, (6) food protein-induced enterocolitis syndrome, (7) severe eczema, and (8) symptoms while breast-feeding. Each of these themes was critically reviewed using all available published data and found that using an AAF in height growth faltering may be indicated. In addition, patients who end up on an AAF often present with multisystem involvement, requiring multiple food eliminations and fall within the more severe spectrum of gastrointestinal allergies. In eosinophilic esophagitis, all current recommendations support the use of an AAF as first-line approach, and in children with anaphylaxis, despite limited evidence an AAF is recommended because of the potential risk for a severe reaction. The use of an AAF in children who are breast-fed remains a highly controversial topic and at all times breast-feeding should be supported in children with CMPA. This article provides a practical guide that is evidence based for health care professionals to the use of AAF.