IGHE and gastroesophageal reflux disease: It can be difficult to distinguish non-IgE-mediated CMA from functional gastrointestinal disorders (FGIDs), gastro-esophageal reflux disease (GERD), or other problems such as neurological, metabolic, endocrine, anatomic, and infectious diseases, since many infants with these conditions exhibit a combination of symptoms, in addition to lack of optimal diagnostic tests and lack of biomarkers.1,6,7