Introduction
Anaphylaxis is defined as a potentially fatal, severe and systemic
allergic reaction that occurs suddenly after contact with an
allergy-causing substance 1. Although rare, deaths
caused by food-induced anaphylaxis are continuing to occur at an
estimated rate of 5 to 200 cases per year in the United States2. Anaphylaxis registries and prospective studies from
the West have reported an increasing trend of anaphylaxis incidence over
time 3-5. In contrast, the burden of anaphylaxis was
thought to be lower in Asia and different from the West in terms of
varying age distribution, anaphylaxis triggers and low usage of
adrenaline auto-injectors (AAI) as first-line treatment6,7. However, a more recent study suggested that
children of Asian ethnicity born in Australia may conversely be at
higher risk of anaphylaxis compared to other ethnicities8. This discrepancy highlights the need for more
accurate estimates of the true anaphylaxis burden in Asian countries.
Time-trend analyses of anaphylaxis incidence across longer time periods,
using a unifying methodology on a territory-wide population, have never
previously been reported.
In this study, we took an advantage of a comprehensive electronic
records system to determine the incidence rates of anaphylaxis between
2009 and 2019 in Hong Kong and investigated the longitudinal trends of
AAI prescriptions.