Time trends in Australian hospital anaphylaxis admissions in 1998-1999 to 2011-2012.

BACKGROUND: Studies from the United Kingdom, the United States, and Australia have reported increased childhood food allergy and anaphylaxis prevalence in the 15 years after 1990. OBJECTIVE: We sought to examine whether childhood food allergy/anaphylaxis prevalence has increased further since 2004-2005. METHODS: We examined hospital anaphylaxis admission rates between 2005-2006 and 2011-2012 and compared findings with those from 1998-1999 to 2004-2005. RESULTS: Overall population food-related anaphylaxis admission rates (per 10(5) population per year) increased from 5.6 in 2005-2006 to 8.2 in 2011-2012 (a 1.5-fold increase over 7 years). The highest rates occurred in children aged 0 to 4 years (21.7 in 2005-2006 and 30.3 in 2011-2012, a 1.4-fold increase), but the greatest proportionate increase occurred in those aged 5 to 14 years (5.8-12.1/10(5) population/y, respectively, a 2.1-fold increase) compared with those aged 15 to 29 years and 30 years or older (a 1.5- and 1.3-fold increase, respectively). Not only did absolute food-related anaphylaxis admissions increase, but the modeled year-on-year rate of increase in overall food-related anaphylaxis admissions also increased over time from an additional 0.35 per 10(5) population/y in 1998-1999 (all ages) to 0.49 in 2004-2005 and 0.63 in 2011-2012 (P < .001). CONCLUSIONS: Food-related anaphylaxis has increased further in all age groups since 2004-2005. Although the major burden falls on those aged 0 to 4 years, there is preliminary evidence for a recent acceleration in incidence rates in those aged 5 to 14 years. This contrasts with the previous decade in which the greatest proportionate increase was in those aged 0 to 4 years. These findings suggest a possible increasing burden of disease among adolescents and adults who carry the highest risk for fatal anaphylaxis.