Necrotizing enterocolitis associated with food protein-induced enterocolitis syndrome: A case report

Introduction: Food protein-induced enterocolitis syndrome (FPIES) is a T-cell-mediated allergy that can occur in newborns and infants who are introduced to milk protein. Some of the serious complications of FPIES include necrotizing enterocolitis (NEC), massive bloody stools, and disseminated intravascular coagulation. Here we report a case of NEC caused by FPIES. Presentation of case: A 28-day-old girl born at full term suddenly developed marked abdominal distention and shock a few hours after being fed highly regulated milk protein. Emergency laparotomy was performed, and extensive small-intestinal necrosis was found. The histological examination showed chronic inflammation with typical ghost crypts, hemorrhage, and extensive pneumatosis intestinalis, a presentation consistent with NEC. Discussion: In this case, the fragile intestinal mucosa associated with FPIES was stimulated by milk protein, leading to NEC. The greatest diagnostic difficulty is the lack of a definitive method for distinguishing between NEC and FPIES. The allergen-specific lymphocyte stimulation test with lactotransferrin was positive, indicating that the primary condition was FPIES. However, no eosinophilic infiltrate was found in the histological examination, but there was chronic inflammation with typical ghost crypts, hemorrhage, and extensive pneumatosis intestinalis. Consequently, the final histological diagnosis in our case was NEC rather than FPIES. Conclusion: FPIES has a variable clinical course, and severe FPIES may become exacerbated even after ingestion of highly regulated milk protein. Taking appropriate actions after correct diagnosis can prevent progression to surgical emergency and secondary NEC.