Although cases of pediatric food allergy anaphylaxis increased in Australia over the last 2 decades, the rate of increase slowed following the release of new guidelines, according to data in The Journal of Allergy and Clinical Immunology.
Doctors historically have advised parents to refrain from introducing their infants to common allergenic foods to prevent food sensitization. But in 2009, the Australasian Society for Clinical Immunology and Allergy (ASCIA) advised against these delays.
Subsequent studies then found that introducing infants to allergens reduced allergy development, prompting ASCIA to recommend early introduction of multiple allergenic foods in 2016.
Raymond James Mullins, MBBS, PhD, FRACP, FRCPA, consultant physician in clinical immunology and allergy at John James Medical Centre in Deakin, Australia, and colleagues examined data from the Australian Institute of Health and Welfare to determine whether the introduction of these guidelines affected food anaphylaxis admission rates.
The researchers compared food anaphylaxis admission rates between 1998 to 1999 and 2006 to 2007, when delayed introduction of allergenic food was recommended; between 2007 to 2008 and 2014 to 2015, when this recommendation was withdrawn; and between 2015 to 2016 and 2018 to 2019, when early introduction of allergens was recommended.
Anaphylaxis admission rates increased in all age groups during the 20-year period, with the highest overall increase among children aged younger than 1 year, increasing by a factor of five, from 14.8 per 105 population to 74.3 per 105 population. Food anaphylaxis admission rates increase by factors of 7.6 among children aged 1 to 4 years, 15.1 among children aged 5 to 9 years, 14.6 among those aged 9 to 14 years and 15.7 among 15- to 19-year-olds.
However, children aged 1 to 4 years and 5 to 9 years twice demonstrated significant reductions in year-on-year rates of increase in food anaphylaxis admissions, the first when delayed introduction recommendations were withdrawn and the second when early introduction of allergens was recommended.
Across the three time periods, the annual year-on-year rates of increase slowed after 2007 to 2008 among children aged 1 to 4 years (17.6%, 6.2%, 3.9% per year) and 5 to 9 years (22%, 13.9%, –2.4%) and after 2015 to 2016 in children aged 10 to 14 years (17.5%, 18%, 10.8%).
However, children aged younger than 1 year experienced accelerations in year-on-year rates of increase (5.2%, 8%, 18%), as did all children aged older than 15 years.
To determine whether the decrease in anaphylaxis admission among those aged 1 to 4 years led to an increase with earlier introduction in infants, researchers examined the year-on-year changes for the combined 0 to 4 years age group. They found that following the 2006 and 2015 guideline updates, year-on-year rates of food anaphylaxis admissions decreased overall for children aged 0 to 4 years, but there was a spike in year-on-year rates of admission for infants aged younger than 1 year.
“The acceleration in food anaphylaxis admissions amongst infants [younger than] 1 year of age is also consistent with the timing of 2016 guidelines to actively introduce allergenic solids in the first year of life, as this could result in earlier presentation of food allergy in those who already have established allergy,” the researchers wrote. “It is important to consider whether the acceleration in food anaphylaxis admissions amongst infants [younger than] 1 year of age, which could be the result of earlier introduction of allergenic food, may cause harm, especially given this population may not have access to weight-appropriate epinephrine autoinjectors. Although fatality from anaphylaxis in infancy is rare, this should be monitored closely to assess potential risks associated with earlier introduction of allergenic foods.”
Overall, the researchers noted the correlation between these changes in rates with the timing of guideline introductions. Although a causal relationship should not be assumed, the researchers continued, these findings indicate that recommendations for early introduction of allergenic foods may be slowing the rate of childhood food allergy.
PERSPECTIVE
The findings of this study are not surprising. There is a trend toward a reduced rate of anaphylactic reactions, with a flattening of the curve. But before we can assess significance, we also need to see more data. Will the trend continue, and will the rates continue to diverge?
Importantly, the authors point out that a true cause-and-effect relationship cannot be established. Therefore, we cannot categorically conclude that the introduction of guidelines is responsible for the trend in reduced anaphylactic reactions.
Still, the data suggest but do not prove that early dietary introduction of allergens may be beneficial as measured by reduced rates of food-induced anaphylactic reactions.
There is a need to continue to educate parents concerning the early dietary guidance. In addition, collection of more data will serve to determine whether rates of anaphylactic reactions will continue to decline as more and more parents heed guidance concerning early allergen dietary introduction.
The authors report an acceleration in food anaphylaxis admissions among infants aged younger than 1 year and speculate this could result in earlier presentation of food allergy in infants who already have established allergy. In other words, as parents introduce more allergens into the diet of infants to prevent food allergy, they may be discovering the child is already allergic.
Data from the Learning Early About Peanut Allergy study suggests there may be a window of opportunity for introduction of allergens, and, ideally, they should be introduced when children are aged 4 to 6 months. Thus, if a well-meaning parent introduces an allergen later — say, between 8 and 12 months — the allergy may have already developed. Hence, the child experiences a reaction.
The impact of timing of allergen introduction within the first year of life on allergy prevention and reduced anaphylactic events requires further investigation.
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