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Background: Eliciting doses (EDs) of allergenic foods can be defined by the distribution of threshold doses for subjects within a specific population. The ED05 is the dose that elicits a reaction in 5% of allergic subjects. The predicted ED05 for peanut is 1.5 mg of peanut protein (6 mg of whole peanut). Objective: We sought to validate the predicted peanut ED05 (1.5 mg) with a novel single-dose challenge. Methods: Consecutive eligible children with peanut allergy in 3 centers were prospectively invited to participate, irrespective of previous reaction severity. Predetermined criteria for objective reactions were used to identify ED05 single-dose reactors. Results: Five hundred eighteen children (mean age, 6.8 years) were eligible. No significant demographic or clinical differences were identified between 381 (74%) participants and 137 (26%) nonparticipants or between subjects recruited at each center. Three hundred seventy-eight children (206 male) completed the study. Almost half the group reported ignoring precautionary allergen labeling. Two hundred forty-five (65%) children experienced no reaction to the single dose of peanut. Sixty-seven (18%) children reported a subjective reaction without objective findings. Fifty-eight (15%) children experienced signs of a mild and transient nature that did not meet the predetermined criteria. Only 8 (2.1%; 95% CI, 0.6%-3.4%) subjects met the predetermined criteria for an objective and likely related event. No child experienced more than a mild reaction, 4 of the 8 received oral antihistamines only, and none received epinephrine. Food allergy–related quality of life improved from baseline to 1 month after challenge regardless of outcome (η2 = 0.2, P < .0001). Peanut skin prick test responses and peanut- and Ara h 2–specific IgE levels were not associated with objective reactivity to peanut ED05. Conclusion: A single administration of 1.5 mg of peanut protein elicited objective reactions in fewer than the predicted 5% of patients with peanut allergy. The novel single-dose oral food challenge appears clinically safe and patient acceptable, regardless of the outcome. It identifies the most highly dose-sensitive population with food allergy not otherwise identifiable by using routinely available peanut skin prick test responses or specific IgE levels, but this single-dose approach has not yet been validated for risk assessment of individual patients.

In 2008, we undertook a survey of food products that carried precautionary labeling within the Australian supermarket setting. We then repeated the same survey in 2011 to examine changes in the prevalence of precautionary labeling over a 3-year period. Our results showed that overall 65% of products contained 1 or more precautionary statements to any of the nine most common food allergens (peanuts, tree nuts, egg, milk, sesame, crustaceans, fish, wheat, and soy). We also have recently examined consumers’ behavior, perceptions, and opinions about precautionary labeling, which showed that even those with a history of anaphylaxis to food appeared to be complacent for avoidance of foods with precautionary labeling, perhaps because of their ubiquity or because the perceived risks are low.

Background Food allergy has been associated with lower weight and height in cross-sectional studies in children; however, this has not been investigated in longitudinal studies to explore growth over time, and previous studies have not accounted for coexisting eczema. Objective The objective of this study was to examine the association of IgE-mediated food allergy and eczema with anthropometric measures at 1 and 4 years of age. Methods In the HealthNuts population-based cohort, infants recruited at age 1 year underwent a skin prick test to egg, peanut, and sesame; those sensitized had oral food challenges. Food challenges repeated at 4 years determined food allergy persistence or resolution. Eczema was defined as parent report of eczema diagnosis. Parent-reported weight and height and child health record data were used to calculate age- and sex-adjusted percentiles from World Health Organization charts. Multivariable linear regression models were fitted to examine the effect of food allergy and eczema on weight and height controlling for potential confounders. Results Children with both food allergy and eczema at age 1 had lower percentiles for mean weight (51.3 vs 58.3 percentile, P = .001) and height (48.4 vs 53.4, P = .028) at age 1 compared with those with neither condition. There was no difference for children with only food allergy or eczema at age 1. By age 4, children with persistent food allergy and persistent eczema, but not those with resolved food allergy, were still shorter and lighter. Conclusions Children with both food allergy and eczema were shorter and lighter throughout early childhood, with more pronounced differences in those with persistent food allergy.

Background Epidemiological evidence has shown that pediatric food allergy is more prevalent in regions further from the equator, suggesting that vitamin D insufficiency may play a role in this disease. Objective To investigate the role of vitamin D status in infantile food allergy. Methods A population sample of 5276 one-year-old infants underwent skin prick testing to peanut, egg, sesame, and cow's milk or shrimp. All those with a detectable wheal and a random sample of participants with negative skin prick test results attended a hospital-based food challenge clinic. Blood samples were available for 577 infants (344 with challenge-proven food allergy, 74 sensitized but tolerant to food challenge, 159 negative on skin prick test and food challenge). Serum 25-hydroxyvitamin D levels were measured by using liquid chromatography tandem mass spectrometry. Associations between serum 25-hydroxyvitamin D and food allergy were examined by using multiple logistic regression, adjusting for potential risk and confounding factors. Results Infants of Australian-born parents, but not of parents born overseas, with vitamin D insufficiency (≤50 nmol/L) were more likely to be peanut (adjusted odds ratio [aOR], 11.51; 95% CI, 2.01-65.79; P = .006) and/or egg (aOR, 3.79; 95% CI, 1.19-12.08; P = .025) allergic than were those with adequate vitamin D levels independent of eczema status. Among those with Australian-born parents, infants with vitamin D insufficiency were more likely to have multiple food allergies (≥2) rather than a single food allergy (aOR, 10.48; 95% CI, 1.60-68.61 vs aOR, 1.82; 95% CI, 0.38-8.77, respectively). Conclusions These results provide the first direct evidence that vitamin D sufficiency may be an important protective factor for food allergy in the first year of life.