Double-blind food challenges in children in general paediatric practice: Useful and safe, but not without pitfalls

Abstract

ObjectiveTo describe results of double-blind placebo-controlled food challenges (DBPCFC) with cow's milk, hen's egg, soy, peanut and hazelnut in general paediatric practice. MethodsFood challenges were performed between January 2006 and June 2011, in children 0–18 years of age, on two half-day hospital admissions with a one-week interval. Tests were performed in a double-blind fashion following a standardised protocol with validated recipes. ResultsOverall, 234 food challenges were performed in 209 children: 160 with cow's milk, 35 with peanut, 21 with hen's egg, 11 with hazelnuts, and 7 with soy. In two thirds of the cases, the DBPCFC was negative (cow's milk: 57.5%; peanut: 40.0%; hen's egg: 66.7%, hazelnut: 90.9%, soy: 100%). The only patient characteristic significantly associated with a positive DBPCFC was the presence of symptoms from three different organ systems (p=0.007). Serious systemic allergic reactions with wheeze or anaphylaxis occurred in only two children (0.9%). Symptoms were recorded on 29.3% of placebo days. In 30/137 children with a negative test (22%), symptoms returned when reintroducing the allergen into the diet, mostly (66.7%) transient. Of the 85 tests regarded as positive by the attending physician, 19 (22.4%) did not meet predefined criteria for a positive test. This was particularly common with non-specific symptoms. ConclusionA DBPCFC can be safely performed in a general hospital for a range of food allergens. The test result is negative in most cases except for peanut. Non-specific symptoms may hamper the interpretation of the DBPCFC, increasing the risk of a false-positive result.