Differentiating Acute Food Protein-Induced Enterocolitis Syndrome From Its Mimics: A Comparison of Clinical Features and Routine Laboratory Biomarkers.

Food protein-induced enterocolitis syndrome (FPIES) is frequently misdiagnosed and subject to diagnostic delay. Profuse vomiting, the cardinal feature of acute FPIES, may occur in more common pediatric disorders such as gastroenteritis and sepsis.We sought to determine differentiating features at acute presentation between FPIES, gastroenteritis, and sepsis in young children presenting to an emergency department (ED) with profuse vomiting.We conducted a retrospective case-control study of children aged 6 months to 4 years with a diagnosis of acute FPIES who had presented to ED and compared the clinical features, vital signs, and routine laboratory studies of this cohort to similarly aged children presenting to ED with vomiting diagnosed with bacterial/viral gastroenteritis or bacterial sepsis.A total of 181 acute FPIES ED presentations were compared with 55 gastroenteritis and 36 bacterial sepsis ED presentations. Children with FPIES were more likely to present with lethargy, floppiness, and pallor. Compared with children with FPIES, children with sepsis were likely to present with fever, tachycardia, tachypnea, and diarrhea, whereas those with gastroenteritis were likely to present with fever, diarrhea, and blood in stools. Normal C-reactive protein (CRP), leucocytosis, lymphocytosis, thrombocytosis, low MPV, and an elevated albumin/globulin ratio were more commonly seen in FPIES than in sepsis or gastroenteritis. No other clinical or laboratory markers examined reliably distinguished between the 3 disease groups.In the young vomiting child, lethargy, floppiness, pallor without fever, and normal CRP should alert clinicians to a possible diagnosis of FPIES. In contrast, a highly elevated CRP is not a feature of FPIES, and in such cases an alternative diagnosis must be considered.