[Clinical characteristics of IgE-mediated cow's milk protein allergy in children]

Objective: To analyze the clinical features of IgE-mediated cow's milk protein allergy (CMPA) in children aged 0-5 years. Methods: This cross-sectional study collected the data on children diagnosed with CMPA in the Department of Allergy at the Children's Hospital of the Capital Institute of Pediatrics from October 2019 to November 2020 and improved peripheral blood routine,total IgE defection, milk specific IgE (sIgE) defection,SPT and milk component defection,diagnosis of severe anaphylaxis based on clinical manifestations. Rank-sum test and chi-square test are used for statistical analysis of clinical characteristics between groups. Results: A total of 106 children (67 boys and 39 girls) were enrolled with the age of 15 (8, 34) months, including 42 cases (≤ 1 year of age), 39 cases (>1-<3 years of age) and 25 cases(≥3 years of age), the onset age of 6 (5, 8) months. Among them, 95 cases (89.6%) were reacted after consuming milk or its products, 42 cases (39.6%) had reaction due to skin contact and 11 cases (10.4%) reacted after exclusive breastfeeding. The onset time of milk product consumption was 45 (1, 120) min, skin contact pathway was 10 (5, 30) min and symptoms in breastfeeding pathway was 121 (61, 180) min. There was statistical difference among the time of symptoms (χ²=77.01, P<0.001).The cutaneous reaction was most common (100 cases, 94.3%), followed by digestive (20 cases, 18.9%) and respiratory (16 cases, 15.1%), and the nervous symptoms (1 case, 0.9%) were uncommon and 24 cases (22.6%) had at least one episode of anaphylaxis. There were 87 cases (82.1%) also diagnosed with other food allergies, 94 cases (88.7%) with previous eczema, 57 cases (53.8%) with history of rhinitis, and 23 cases (21.7%) with history of wheezing. The total IgE level was 191.01 (64.71, 506.80) kU/L, and the cow's milk sIgE level was 3.03 (1.11, 15.24) kU/L. The maximum diameter of the wheal in SPT was 8.2 (4.0, 12.0) mm. Component resolved diagnosis showed that 77 cases (81.9%) were sensitized to at least one out of 4 main components, including casein, α lactalbumin, β lactoglobulin and bovine serum albumin.The possibility of anaphylaxis in children with milk sIgE grade Ⅳ-Ⅵ was higher than that in children with grade 0-Ⅲ (57.7% (15/26) vs. 12.5% (10/80), OR=9.545, 95%CI 3.435-26.523). Children with milk SPT ≥+++ had a higher probability of anaphylaxis than those with milk SPT ≤++ (34.4% (11/32) vs. 11.5% (3/26), OR=4.016, 95%CI 0.983-16.400). Anaphylaxis were more common in α lactalbumin positive children than in negative children (34.3% (13/38) vs. 14.2% (8/56), χ²=1.23，P=0.042). Conclusions: CMPA in children has early onset and diversified clinical manifestations, which are mainly cutaneous symptoms. Most children are sensitized to at least one allergen component. Serum sIgE level, SPT reaction and allergen components play important roles in the diagnosis and evaluation of CMPA, and higher milk sIgE level may predict a higher risk of anaphylaxis.