Increasing trend of tree nuts in a comprehensive survey of pediatric anaphylaxis in Aichi Prefecture, Japan

Abstract

Objective: This study aimed to clarify the current status of tree nuts in a comprehensive analysis of pediatric anaphylaxis cases.

Methods: The Aichi Medical Association surveyed pediatric anaphylaxis cases aged under 15 years from 87 secondary and 25 tertiary emergency care hospitals in Aichi Prefecture (population 7.5 million), Japan.

Results: Of the 2,480 food-induced anaphylaxis cases identified between April 2017 and March 2021, 308 were tree-nut-induced. The cases per year was 40, 74, 94, and 100 in 2017, 2018, 2019, and 2020, respectively. Egg and milk were the most frequent among food triggers in 2017, while the greatest proportional increase was observed in tree nuts from 6.0% in 2017, ranking fourth, to 18.8% in 2020, ranking first. Tree nuts were the first-ranking causative food in the 1, 2- and 3-6-year-old groups in 2020. Overall, 189 (61.8%) cases were admitted to the hospital, of which three were admitted to the intensive care unit. A total of 147 were treated with adrenaline, and 55 cases included previously prescribed adrenaline auto-injectors. Walnut (45.5%) accounted for the highest incidence among tree nuts, followed by cashew (20.1%), macadamia, and pistachio.

Conclusions: The proportion of tree nuts in food-induced anaphylaxis has increased.