Sensitization to Cor a 9 and Cor a 14 is highly specific for a hazelnut allergy with objective symptoms in Dutch children and adults.

BACKGROUND: Component-resolved diagnosis has been shown to improve the diagnosis of food allergy. OBJECTIVE: We sought to evaluate whether component-resolved diagnosis might help to identify patients at risk of objective allergic reactions to hazelnut. METHOD: A total of 161 hazelnut-sensitized patients were included: 40 children and 15 adults with objective symptoms on double-blind, placebo-controlled food challenges (DBPCFCs) and 24 adults with a convincing objective history were compared with 41 children and 41 adults with no or subjective symptoms on DBPCFCs (grouped together). IgE levels to hazelnut extract and single components were analyzed with ImmunoCAP. RESULTS: IgE levels to hazelnut extract were significantly higher in children with objective than with no or subjective symptoms. In 13% of children and 49% of adults with hazelnut allergy with objective symptoms, only sensitization to rCor a 1.04 was observed and not to other water-soluble allergens. Sensitization to rCor a 8 was rare, which is in contrast to rCor a 1. Sensitization to nCor a 9, rCor a 14, or both was strongly associated with hazelnut allergy with objective symptoms. By using adapted cutoff levels, a diagnostic discrimination between severity groups was obtained. IgE levels to either nCor a 9 of 1 kUA/L or greater or rCor a 14 of 5 kUA/L or greater (children) and IgE levels to either nCor a 9 of 1 kUA/L or greater or rCor a 14 of 1 kUA/L or greater (adults) had a specificity of greater than 90% and accounted for 83% of children and 44% of adults with hazelnut allergy with objective symptoms. CONCLUSION: Sensitization to Cor a 9 and Cor a 14 is highly specific for patients with objective symptoms in DBPCFCs as a marker for a more severe hazelnut allergic phenotype.

Can we predict severe reactions during peanut challenges in children?

BACKGROUND: Limited and contrasting data are available about risk factors for severe reactions during double-blind, placebo-controlled food challenge (DBPCFC). Knowing these risk factors would help to improve safety precautions and choosing the best setting for challenge. We assessed whether we could determine predictors for positive and severe food challenge outcome (FCO) with regular available patient data in children suspected for peanut allergy. METHODS: A retrospective study in children referred for DBPCFC with peanut was performed during a 3-year period. Reactions during challenge were classified as mild/moderate (Sampson's grade 1-3) and severe (Sampson's grade 4-5). We performed uni- and multivariable logistic regression to determine predictors for positive and severe FCO. RESULTS: A group of 225 children with a median age of 6.7 (IQR 5.0-9.5) years were studied. In 109 (48%) children, food challenge outcome was positive and 24 (11%) children developed a severe reaction. The level of sIgE for peanut OR 1.14 (1.08-1.20), male gender OR 0.40 (0.20-0.81), having another food allergy OR 0.43 (0.20-0.88), were independently related to positive FCO. No significant differences were found between children with severe and non-severe FCO with respect to age, gender, asthma, sIgE, or previous reaction to peanut. CONCLUSIONS: Although predictors of positive FCO could be identified, none of the studied risk factors could predict a severe reaction during peanut challenge. When challenging a child sensitized to peanut, clinicians should be prepared and equipped to handle any reaction in all cases.

A prediction rule for food challenge outcome in children.

BACKGROUND: In children with food-related symptoms, a food challenge is considered as the gold standard to diagnose allergy. If food allergy could be predicted by patient history and/or diagnostic tests, the number of time-consuming and sometimes risky food challenges could be decreased. We aimed to determine questionnaire and test-based characteristics, to predict the food challenge outcome (FCO) in children referred to a tertiary centre for the evaluation of food-related symptoms. METHODS: Pre-challenge standardized questionnaires, skin prick tests (SPT), and specific IgE levels (sIgE) were obtained in patients that underwent a food challenge in our hospital in 2009. Characteristics of patients with positive and negative FCO were compared, and uni- and multivariate associations between predictors and FCO were calculated. Based on the multivariate model, a risk score was developed to predict the FCO. RESULTS: One hundred and twenty-nine challenges were analyzed, 41.9% had a positive outcome. Median age of both groups was 4.9 yrs (range 2.8-8.3). Patients with a positive FCO reacted faster with symptoms after allergen ingestion and had higher sIgE levels compared to children with negative FCO. A clinical risk score was developed based on the index food, 'time between allergen ingestion and complaints' and sIgE levels (range 0-10). The prognostic capacity of this model (AUC) was excellent (0.90). The very high- and low-risk groups (24% of patients) are both predicted excellent without misclassification. CONCLUSION: Positive FCO can be predicted by the index food, time between allergen ingestion and development of symptoms, and the sIgE level.