First report of euglena-induced anaphylaxis: A case study.

Euglena, a microalga with photosynthetic capabilities, has become increasingly popular in Japan as a health food and supplement owing to its rich nutrient profile. However, their potential to cause allergic reactions remains largely unknown. We report the first case of anaphylaxis induced by euglena in a 48-year-old Japanese woman with a history of urticaria and oral allergy syndrome. She had been consuming a Euglena-containing supplement for nearly a decade, increasing her intake in the 3 months preceding her initial visit. She experienced recurrent anaphylactic episodes, including urticaria, abdominal pain, palpitations, and vomiting. Diagnostic tests, including histamine release and skin-prick tests, confirmed an immediate allergic reaction to Euglena. Following discontinuation of the Euglena-containing supplement, her symptoms resolved completely. As the consumption of Euglena-based products continues to increase, the possibility of Euglena-induced allergic reactions should be considered, and further research into its allergenic components is necessary.