Soy hypersensitivity in children with food allergy.

To evaluate humoral (IgE antibodies) and clinical (positive challenge test) soy hypersensitivity prevalence, we studied 317 children (271 boys and 100 girls) with a median age of 5 months (range 1-120) who visited the Division of Allergy and Clinical Immunology of the Pediatric Department of the University of Roma "La Sapienza" because of histories and symptoms suggestive of food allergy. Atopic dermatitis (AD) was present in 247/317 children (78%), diarrhea in 19 (6%), urticaria in 22 (7%), and rhinitis and/or asthma in 29 (9%). All children underwent diagnostic procedures including family and personal history, physical examination, PRIST, and RAST to cows milk (CM), egg, wheat, soy, and Dermatophagoides pteronyssinus (Dpt). Open challenge tests to soy were performed in the hospital under observation and with emergency equipment at hand. The prevalence of humoral sensitization to CM was 54%, to egg 46%, to Dpt 35%, to wheat 24%, and to soy 22%. Only five children had IgE only to soy; six to soy and egg; and 58 to soy, CM, and egg. Only ten children (3%) had positive challenge to soy and only five of them had IgE to soy. RAST had a sensitivity of 0.69, a specificity of 0.83, a negative predictive value of 0.77, and a positive predictive value of only 0.06.