Aim: To analyze the results of a systematic survey of biological tests in a symptomatic pediatric population consulting for the exploration of a possible food allergy.
Patients and methods: 406 children included in this study, mean age 3.3+3.2 years (2 months-16 years), 159 girls and 247 boys, had cutaneous tests (Stallergènes, Paris, France), assaying of total and specific IgE, and RAST Fx5 (Pharmacia & Upjohn Diagnostics AB, Uppsala, Sweden). Those children suffering from eczema (34.9%), digestive disorders (26.1%), ORL and pulmonary (8.3%), anaphylactic choc (3.4%) or mixed symptoms (27.3%).
Results: The overall positivity of cutaneous tests, all confused age periods, was 34.1% with the following order: egg white (52%, p < 0.05 vs. other food), peanut (46%), egg yolk (42%), fish (34%), wheat (33%), soy (32%), cow's milk (24%) and rice (17%). It decreased significantly with age only for the egg white, 61% (0-1 year) and 68% (1-2 years) vs 31% (> 6 years), p < 0.05. The positivity of cutaneous tests for egg and peanut was more frequent with eczema than with digestive manifestations (64% vs. 44%, 57.6% vs. 34% and 56% vs. 38.7%, p < 0.05). The title of total IgE increased with age, r 0.5 p 0.001. The positivity of specific food IgE was more frequent at 4-6 years (68%) than at 0-1 year (36%), p < 0.05. It revealed, all confused age periods, the following order: egg white (74%) and peanut (64%), p < 0.05 vs. other food, cow's milk (59%), wheat (55%), soy (45%) and fish (24%). The number of high specific food IgE titers was significantly higher than the number of positive cutaneous tests by order of frequency; egg white, peanut, cow's milk, wheat and soy, p < 0.05; the reverse was observed for fish, p < 0.05. Percentage of subjects combining a high title of specific food IgE and a positive cutaneous test for egg white (39.4%) was significantly higher than the percentage of those combining a high RAST Fx5 title and a positive cutaneous test for at least one of 6 corresponding foods (25.2%), p < 0.05.
Conclusion: The positivity of different food cutaneous tests, the rate of total and specific IgE titers and the agreement of the results varied according to age, food and symptoms.