Objective: Skin prick testing with commercial allergens is the most commonly used method for detection of food specific IgE. However, standardized commercial products are not available for most of the allergens and it has been shown that some patients with a history of food allergy having negative skin prick test results with commercial allergens, have positive results with the raw extracts of the same foods. In this study, we aimed to compare the results of skin prick tests performed with commercial and raw cow`s milk and egg white extracts and evaluate their correlation with serum specific immunoglobulin E levels.
Materials and Methods: We conducted a retrospective analysis of patients having symptoms of allergic diseases who were performed skin prick tests with raw and commercial extracts of cow`s milk and egg white at pediatric allergy department. Presenting symptoms, family history and laboratory findings were obtained from regular medical records.
Results: A total of 130 patients with a mean age of 12.1 ± 17.3 were enrolled in the study and 66.7% (88) of them were male. Within the skin prick tests with cow`s milk and/or egg white, 90.4% of them were positive with raw extracts and 72.1% were positive with commercial extracts. Egg white specific IgE levels were positive in 77.8% of patients having positive skin prick test only with raw egg white, while it was positive in 10.0% of patients having positive skin prick test only with commercial egg white allergen (p= 0.001). A total of 21 patients had positivite skin prick tests only with raw cow`s milk and 20 of them have also positive cow`s milk specific IgE levels. Egg white specific IgE levels were positive in 78.2% of patients having greater enduration with raw egg white, while it was positive in 8.3% of patients having greater enduration with commercial egg white allergen (p< 0.001). The mean cow`s milk specific IgE level was 7.0 ± 9.8 in patients having greater enduration with raw cow`s milk and there was one patient who had higher enduration with raw cow`s milk and his specific IgE level was 0.41.
Conclusion: The positivity rate and mean diameter of enduration with raw food extracts was higher than commercial extracts. And also correlation with serum specific IgE levels and raw food extracts was more significant than the correlation with commercial extracts.