Association of food allergy and atopic dermatitis exacerbations.

BACKGROUND: Atopic dermatitis (AD) and food allergy frequently coexist in children. OBJECTIVE: To examine the association between food allergy and AD. METHODS: Between 2001 and 2011, children referred to our tertiary care center underwent double-blind, placebo-controlled food challenges (DBPCFCs) for one or more suspected food allergies as part of regular care. Immediate reactions were observed and recorded by allergy nursing staff, whereas late reactions were ascertained by semistructured telephone interview 48 hours after challenge. To test to which degree specific IgE results were predictive in the outcome of DBPCFCs in children with and without (previous and current) AD, logistic regression analysis was performed. RESULTS: A total of 1186 DBPCFCs were studied. Sensitization to foods occurred significantly more often in children with previous AD. The association between specific IgE results and the outcome of DBPCFCs was significant for children with and without (previous and current) AD but stronger for children without current AD. The positivity rate of DBPCFCs in children with mild, moderate, and severe AD was 53.3%, 51.7%, and 100%, respectively. Children with AD and a history of worsening AD as their only symptom reacted as often to placebo as to challenge food. CONCLUSION: Children with current AD are more frequently asymptomatically sensitized to the foods in question than those without AD. In addition, children suspected of food allergy should be considered for testing, regardless of the severity of their AD. Our results suggest that children with exacerbation of AD in the absence of other allergic symptoms are unlikely to be food allergic.

Development and validation of challenge materials for double-blind, placebo-controlled food challenges in children.

BACKGROUND: The use of double-blind, placebo-controlled food challenges (DBPCFCs) is considered the gold standard for the diagnosis of food allergy. Despite this, materials and methods used in DBPCFCs have not been standardized. OBJECTIVE: The purpose of this study was to develop and validate recipes for use in DBPCFCs in children by using allergenic foods, preferably in their usual edible form. METHODS: Recipes containing milk, soy, cooked egg, raw whole egg, peanut, hazelnut, and wheat were developed. For each food, placebo and active test food recipes were developed that met the requirements of acceptable taste, allowance of a challenge dose high enough to elicit reactions in an acceptable volume, optimal matrix ingredients, and good matching of sensory properties of placebo and active test food recipes. Validation was conducted on the basis of sensory tests for difference by using the triangle test and the paired comparison test. Recipes were first tested by volunteers from the hospital staff and subsequently by a professional panel of food tasters in a food laboratory designed for sensory testing. Recipes were considered to be validated if no statistically significant differences were found. RESULTS: Twenty-seven recipes were developed and found to be valid by the volunteer panel. Of these 27 recipes, 17 could be validated by the professional panel. CONCLUSION: Sensory testing with appropriate statistical analysis allows for objective validation of challenge materials. We recommend the use of professional tasters in the setting of a food laboratory for best results.