Participant Population and History Collection
The study population comprised 200 physician-diagnosed fish-allergic patients recruited from five regional hospitals in Hong Kong (Prince of Wales Hospital, Queen Mary Hospital, Queen Elizabeth Hospital, Yan Chai Hospital and Princess Margaret Hospital) from 2019 to 2023. Subjects were recruited when they had a convincing history of immediate fish allergy as defined by immediate allergic symptoms within 2 hours following fish ingestion within two years before recruitment. Demographic data of the study population as well as their clinical history was collected with a standardized questionnaire. All participants were asked to indicate all fish species they had tried, including those eliciting an allergic response and tolerated without any symptoms, as well as their consumption pattern of fish in the past two years. Participants and/or their legal guardians gave written informed consent. Ethical approvals were obtained from the Joint Chinese University of Hong Kong-New Territories East Cluster Clinical Research Ethics Committee (reference 2019.612)