Published Online: April 25, 2016
Food allergy is a common condition, and the number of children diagnosed with food allergy appears to have rapidly increased over the past few decades. Previous studies have also suggested that this increase has been particularly apparent among non-Hispanic Black children. Most of these studies, however, have been based on self-reported food allergy and health care utilization data, and it is not known whether this trend has been accompanied by changes in allergic sensitization (presence of food-specific IgE).
In a recent article published in The Journal of Allergy and Clinical Immunology: In Practice, McGowan et al measured food-specific IgE levels for peanut, milk, egg, and shrimp in stored blood from a nationally representative survey conducted between 1988 and 1994 (the National Health and Nutrition Examination Survey [NHANES] III) and compared levels of sensitization to that previously measured in NHANES 2005-2006. The same laboratory did the analyses in both surveys using the same methods. Their primary objective was to determine whether there had been increases in allergic sensitization to foods over the same time period that self-reported food allergy increased. They were also interested in whether these trends differed by race/ethnicity.
A total of 7896 children (4995 from NHANES III and 2901 from NHANES 2005-2006) were included. In contrast to the researcher’s expectations, the number of children who had a positive IgE to at least one food decreased slightly from NHANES III (24.3%), to NHANES 2005-2006 (21.6%). Interestingly, there were no significant changes in the prevalence of milk, egg, or peanut sensitization, but shrimp sensitization appeared to decrease between NHANES III and NHANES 2005-2006. Among non-Hispanic Black children, there was a trend towards increased moderate- and high-level sensitization to milk, egg, and peanut, but this was not seen in the other racial/ethnic groups.
This study is the first to examine the change in food-specific IgE levels to common food allergens in the general U.S. population over time. The surprising results that a biomarker of food allergy (food specific IgE) did not increase over the same decades when self-report of food allergy did suggests that the increase in self-reported and diagnosed food allergy in the U.S. over the past several decades may not be due to increased sensitization to common food allergens. The authors suggest that this discrepancy may be due to either a change in the relationship between food sensitization and clinical allergy or in the recognition and diagnosis of food allergy, both of which warrant further study.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.