Food Protein-Induced Enterocolitis Syndrome Masquerading as Sepsis in Early Infancy.

Food protein-induced enterocolitis syndrome (FPIES) is a less common etiology of vomiting in an infant and can be challenging to diagnose. The absence of confirmatory laboratory testing or clear clinical criteria and signs/symptoms that overlap with other entities can lead to instances of misdiagnosis. We present a case of an exclusively breastfed infant who presented with emesis and dehydration. The infant was initially diagnosed with and treated for sepsis but was eventually diagnosed with FPIES. We discuss challenges in making a diagnosis of FPIES and potential factors that can distinguish it from sepsis.