Comparison of methemoglobin levels in food protein-induced enterocolitis syndrome and other gastrointestinal diseases in neonates

Abstract

Introduction and objectives: Methemoglobinemia has been reported to be associated with severe food protein-induced enterocolitis syndrome (FPIES). However, no reports have evaluated methemoglobin (MHb) levels in FPIES without symptomatic methemoglobinemia or the usefulness of MHb measurement for the diagnostic prediction of FPIES. To evaluate the MHb levels of patients with neonatal-onset FPIES and determine whether MHb levels are higher in FPIES than in other gastrointestinal diseases.

Patients and methods: Eleven neonates with severe acute FPIES (FPIES group) and 139 neonates with other gastrointestinal diseases (non-FPIES group) were included in this study. Patient characteristics, symptoms, and venous blood test values (MHb, pH, HCO₃^-, and C-reactive protein) were evaluated.

Results: The median age at onset was 16 days vs. 1 day; males comprised 64% vs. 46%, the median gestational age was 38 weeks vs. 38 weeks, the median birth weight was 2710g vs. 2880g, and the median hospitalization duration was 31 days vs. 6 days for the FPIES vs. non-FPIES groups, respectively. MHb (%) was higher in the FPIES group than in the non-FPIES group [median (range), 1.1 (0.6-10.9) and 0.6 (0.3-1.2), respectively, p<0.001]. There were no differences in terms of pH, HCO₃^-, and C-reactive protein (p>0.05). In the receiver operating characteristic analysis for FPIES diagnosis based on MHb (%), the area under the curve was 0.885, specificity was 97.1%, and sensitivity was 72.7% at a MHb cutoff of 1.0.

Conclusion: High MHb levels may help diagnose severe acute FPIES in neonates, but careful evaluation is needed.

Keywords: Food allergy; Food protein-induced enterocolitis syndrome; Methemoglobin; Milk allergy; Newborn.