[Evaluation of the RAST in the diagnosis of children with food allergy].

Our objective was to evaluate the diagnostic value of RAST in children with symptoms of airways allergy and probable food allergy. We studied 17 children under 6 years old with rhinitis or asthma. The underwent a food elimination diet during 4 weeks followed by weekly ambulatory oral food challenge. Cough, wheezing, dyspnea, rhinorrea and nasal itch and blockage were evaluated, daily by their parents and weekly at the hospital. We found no difference between the clinical evaluation made by their parents and at the hospital. We found 16/76 positive oral food challenges. RAST was positive in 44 foods. Cow's milk and egg were the more frequent positive foods both in oral challenge and RAST, 5 and 6, and 14 and 14, respectively. Serum IgE had an average of 350 UI/ml. RAST evaluation results were sensitivily 62.5%, specificity 43.3%; positive predictive value 22.7%, negative predictive value 81.3% and total efficacy 47.4%. We can conclude that food allergy can be a frequent cause of airways allergy symptoms in children under 6 years old and although in cases, RAST is considered the best in vitro diagnostic test, its results should be symptoms related and cautiosly interpreted.