Evaluation of epidermal prick test and specific IgE test in patients with cow's milk allergy

Food allergy is more common in the first years of life with its frequency gradually decreasing after the age of three. Four to six percent of children in the world have been known to have food allergies. Foods that frequently cause allergies in childhood (such as cow's milk, eggs, wheat) are crucial nutrients in the child's diet. Cow milk and eggs take the first place among foods that cause food allergy in infancy. Cow's milk allergy is defined as an immune reaction to one or more cow's milk proteins. The diagnosis of allergic diseases is directly related to good medical history, physical examination and clinician experience, and some tests are used as diagnostic support. These tests can be divided into two groups as in vivo and in vitro tests. Whereas in vitro tests are cellular tests such as serum total IgE, specific IgE (SpIgE), eosinophil counts, and basophil mediator secretion test, in vivo tests can be classified as skin tests and provocation tests. The double-blind placebo-controlled food challenge (DBPCFC) is specified as the gold standard among all tests. Recent evidence suggests that SpIgE measurements can predict the result of the DBPCFC. When a comprehensive medical history is combined with the SpIgE measurement, fewer patients may require a provocation test. In the present study, we aimed to investigate the relationship between EPT (Epidermal Prick Test) and SpIgE, performed for diagnostic purposes in patients between 0-18 years of age who applied to Akdeniz University Pediatric Allergy and Immunology outpatient clinic between 01.04.2017 – 01.04.2019, and diagnosed with cow's milk allergy. The records of patients diagnosed with cow's milk allergy who had applied to Akdeniz University Faculty of Medicine Pediatric Allergy-Immunology clinic between 01.04.17 and 01.04.19 were analyzed retrospectively via hospital registry. The analysis results of the comparison of the demographic data of the patients included in the study and the results of SpIgE and nutritional EPT were evaluated. In total, 146 patients were included in the study and, 61 of the patients were female (41.8%) while 85 (58.2%) were male. The median age of the patients was 36 months (12-22 months) and the median age at test time was 12 months (1-196 months). According to SpIgE or food EPT positivity, cow milk was identified as a responsible allergen in 133 patients (91.1%), egg white in 112 patients (76.7%), egg yolk in 73 patients (50%), wheat in 41 patients (28.1%), 19 patients ( 13%) fish, seafood in 2 patients (1.4%), fish and seafood in 20 patients (13.7%), nuts in 68 patients (46.6%) and other foods in 69 patients (47.3%). Whereas 6.2% of patients had a single allergy, 93.8% had multiple food allergies. Among 5 patients (100%) with anaphylaxis, all had skin findings, 2 (40%) had GIS findings and 4 (80%) had respiratory system findings. The risk of anaphylaxis was found to be significantly higher in patients with angioedema than ones without angioedema (OR: 109,714; 95% CI: 4,455-2701,853; p = 0.004). Risk factors that independently affect the occurrence of anaphylaxis in patients included in the study were analyzed with multivariate logistic regression analysis. The risk of anaphylaxis was found to be significantly higher in patients whose mother had experienced stress during pregnancy than those who had not (OR: 22,897; 95% CI: 1,258-416,83; p = 0.034). Although the gold standard in the diagnosis of food allergy is DBPCFC, it is not practical. Thus we made a clinical diagnosis. Further studies are needed on that issue. Keywords: Food allergy, cow's milk, SpIgE, EPT