PURPOSE OF THE STUDY.
The goal of this study was to determine if component-resolved testing will aid in determining patients at risk for allergic reactions to hazelnut.
A total of 161 adults and children with sensitization (≥0.35 kUA/L) to hazelnut were retrospectively recruited between 2010 and 2012 at the University Medical Center Utrecht (Utrecht, the Netherlands).
Forty children and 15 adults with objective symptoms on double-blind, placebo-controlled food challenges (DBPCFCs) and 24 adults with a convincing history of reaction were compared with 41 children and 41 adults with no symptoms on DBPCFCs. Specific IgE levels to hazelnut extract and single components were analyzed with ImmunoCAP and compared between the study groups. The diagnostic value of IgE levels for discrimination between hazelnut allergy with objective symptoms and no or subjective symptoms was determined by calculating the area under the curve of the receiver-operating characteristic.
Asthma was more common among adults with hazelnut allergy with objective symptoms than those with no or subjective symptoms (P = .03). Asthma was more common in children than adults with no or subjective symptoms of hazelnut allergy (P = .04). All children and most adults (97%) with subjective hazelnut allergy were sensitized to birch pollen. Sensitization to nCor a 9, rCor a 14, or both was strongly associated with hazelnut allergy with objective symptoms. IgE levels to either nCor a 9 of ≥1 kUA/L or rCor a 14 of ≥5 kUA/L in children had a sensitivity of 83% and a specificity of 93%. In adults, the combination of IgE to either nCor a 9 or rCor a 14 of ≥1 kUA/L had a specificity of 98%.
Sensitization to Cor a 9 and Cor a 14 is specific for patients with objective symptoms in DBPCFCs to hazelnut.
IgE-specific food allergy testing has been plagued by poor specificity, resulting in many patients being incorrectly labeled food allergic. Component testing as demonstrated in this study may improve specificity for certain foods. As the authors note, food challenges are still needed to confirm tolerance, but component testing may allow additional patients to proceed to food challenge. Patient’s sensitivities to specific components have been shown to vary regionally. When treating diverse patient populations, we must consider these possible regional variations.
- Copyright © 2014 by the American Academy of Pediatrics