Rationale: Anaphylaxis is a serious, generalized allergic reaction typically triggered by drugs, food, and bee venom, which can be life-threatening. Seeds are one of the major food allergens and can cause anaphylaxis as well as systemic hypersensitivity reactions. Flaxseed has been widely used crop for numerous purposes, such as in alternative medicine and as a dietary supplement, hypersensitivity to it has rarely been reported.
Patient concerns: A 42-year-old female presenting with facial edema, dyspnea and urticaria after ingested half teaspoon of flaxseed flour 30 minutes previously.
Diagnoses: A skin prick test for heated flaxseed flour extract showed negative responses, but intradermal test showed positivity which suggested an Immunoglobulin E-mediated reaction.
Interventions: The patient was instructed to avoid future ingestion of flaxseed.
Outcomes: The patient had no recurrence of symptoms at 1-year follow-up.
Lessons: This is the first case of flaxseed-induced anaphylaxis in Korea, confirmed by an intradermal skin test.