Characterizing biphasic food-related allergic reactions: US food allergy registry

Published: May 22, 2021

The incidence of biphasic food-related allergic reactions ranges from 1% to 20% of anaphylactic reactions. However, the majority of these estimates come from individuals undergoing oral food challenges or physician confirmed biphasic anaphylaxis, and little is known about the incidence of biphasic reactions that occur in individuals with mild initial reaction symptoms, managed by the patient and/or family.

In a recent study published in The Journal of Allergy and Clinical Immunology: In Practice, Gupta et al, utilized 2 patient registry surveys established by Food Allergy Research & Education (FARE) to characterize the experiences of individuals who reported biphasic food-related allergic reactions during their most recent reaction. The analytic sample included parent/guardian respondents (reporting on behalf of their food-allergic children and young adults up to 26 years of age) and self-respondents (adults with FA over 18 years of age who responded for themselves).

This study found that the incidence of reported biphasic reactions was 16.4% (CI: 15.3-17.7). 12.8% (CI: 12.5-14.3) of parent/guardian respondents and 21.8% (CI: 19.7-23.8) of self-respondents indicated a biphasic reaction during their most recent food-allergic reaction. Among respondents with a mild initial reaction, 7.4% reported a biphasic reaction compared with 30% with a very severe initial reaction. When the initial reaction was mild, 69.6% of parent/guardian respondents and 52.0% of self-respondents with a biphasic reaction reported a mild secondary reaction. When the initial reaction was very severe, 36.3% of parent/guardian respondents and 42.9% of self-respondents with a biphasic reaction reported a very severe secondary reaction. Female gender, Black race, reaction age 5-12 and 26-66 years, initial moderate, severe, or very severe reaction, and one or more annual reactions were associated with increased odds of a biphasic reaction.

The findings of this study suggest that 1 in 6 respondents perceived a secondary reaction and severity of the secondary reaction was most similar to the perceived initial reaction severity. Biphasic reactions occurred more frequently with severe initial reactions. These data are helpful to better understand the risk for and potential severity of biphasic food-related allergic reactions.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

Full Article