Saccharomyces boulardii as a single trigger of food protein-induced enterocolitis syndrome: Seven case reports.

Background: Food protein-induced enterocolitis syndrome (FPIES) is the most serious type of non-immunoglobulin E (IgE)-mediated food allergic reaction manifesting as sepsis-like symptom, which can lead to shock. Saccharomyces boulardii (S. boulardii), a probiotic prescribed frequently in clinical settings, has been reported to trigger FPIES in an infant with soy-triggered FPIES. In this report, we describe a new clinical FPIES in which S. boulardii was the sole triggering factor of acute FPIES adverse reaction in seven healthy infants.

Case summary: Seven FPIES cases triggered by only S. boulardii were gathered from 2011 to the present. None of the patients had previously experienced any allergic reaction to cow's milk, soy, or complementary food. The age of the patients was 4-10-months old, and the symptoms of FPIES developed after ingestion of S. boulardii, which is mostly prescribed for the treatment of gastroenteritis or antibiotic-associated diarrhea. All patients experienced severe repetitive vomiting 1-3 hours after S. boulardii ingestion. Extreme lethargy, marked pallor, and cyanosis were also observed. No IgE-mediated hypersensitivity developed in any patient. Diarrhea was followed by initial intense vomiting in approximately 5-10 hours after S. boulardii ingestion, and only one case showed bloody, purulent, and foul-smelling diarrhea. The patients stabilized quickly, mostly within 6 hours. Symptoms got all improved within 24 hours after discontinuation of S. boulardii.

Conclusion: S. boulardii can be the sole trigger of acute FPIES and be prescribed cautiously even in healthy children without FPIES.