Oral food challenges: result of a 16-year experience at a major teaching hospital in Thailand

BACKGROUND: Prevalence of food allergy is increasing all over the world including in Asia. Diagnosis of food allergy in Asia is usually made after family complaints or by elimination and/or reintroduction foods. This could lead to an inaccurate diagnosis and to incorrect information on epidemiology of food allergy. We, herein, reported results of a 16-year experience (1996–2012) of oral food challenge (OFC) performed in pediatric patients at a major teaching hospital in Thailand. OBJECTIVE: The major objectives of this report are to review types of foods selected for oral challenges, frequency of positive/negative challenges to these foods and the clinical reactions during challenges among these children. METHODS: Medical records of 206 children underwent OFC between 1996 and 2012 for various indications at the Allergy clinic of Pediatric Department, Siriraj Hospital, Mahidol University (age range, 4 months to 17 years) were retrospectively reviewed. Data including clinical data, skin prick test results and specific IgE levels were analyzed with respect to challenge results (positive/negative). During the period of the study, 2 separate investigations on shrimp allergy and wheat allergy were conducted. RESULTS: Sixty of 206 children (29%) had positive OFC, whereas 84 out of 306 OFC (27.5%) were positive. The most common food giving positive challenges in this study was shrimp (40%). Among children less than 3 years of age, the most common food with positive challenge was wheat (70%) whereas among children 3 years of age or older, shellfish was the most common food (42%). Cutaneous reactions were the most common reactions observed. CONCLUSION: Only 1 out of 3 children underwent OFC in this study had positive challenges. Shrimp was the most common food causing challenge in this study especially among children older than 3 years of age. Wheat has become another leading food besides cow's milk and egg in causing positive OFC in younger children in Thailand.