The long-term clinical course of protein-losing enteropathy combined with iron deficiency anemia in Korean toddlers: Possible association with cow's milk protein.

Background: Protein-losing enteropathy (PLE), a rare condition with excessive gastrointestinal protein loss, presents with hypoalbuminemia, edema, or ascites. Several cases of PLE combined with severe iron deficiency anemia (IDA) have been reported in infants and toddlers that were considered to result from excessive cow's milk consumption, although the mechanism has not been clearly established.

Methods: We retrospectively reviewed the clinical, laboratory, endoscopic, and radiologic characteristics of patients diagnosed and treated for PLE with IDA between 2015 and 2021. Long-term outcomes were analyzed according to dietary intervention during the follow-up period.

Results: A total of 10 patients aged 7.0-26.7 months were enrolled in the study and the median follow-up duration of them was 9.4 months (range, 1.3-18.0). Six of them were fed powdered formula, while two were fed whole cow's milk, and their median daily intake was 700 mL (range, 300-900). The times to normalization of hemoglobin, albumin, and eosinophil count were shorter in patients with dietary elimination of cow's milk protein immediately after diagnosis compared to those with reduced intake or no dietary change.

Conclusion: Early complete elimination of cow's milk protein should be considered, especially if the laboratory parameters are not normalized with adequate iron supplementation even though the clinical symptoms show improvement. We would like to draw attention to the possibility of the cow's milk protein in the pathogenesis of the condition through the non-IgE-mediated immune reactions.