Аllergic sensitization in children with atopic dermatitis in the first 2 years of life according to the results of skin tests

Abstract

Atopic dermatitis (AD) is associated with food allergies (FA), which frequency and structure varies from region. The objective of the research was to determine the structure of FA in children (<2 years) with AD and to analyze age-specific sensitization. Methods. 79 children with AD aged 2-24 months were examined (Russia, Moscow). Skin prick tests (SPT) with food allergens were used to determine sensitization, if necessary additional SPT with aeroallergens were performed. Results. 51.9% of patients had hypersensitivity to at least 1 allergen. Positive SPT for egg were detected in 38.0%, cow's milk - in 27.8%, fish - in 10.1%. Allergy to fish occurred predominantly in the 2nd year of life (35.0% vs 4.8, p=0.02). Soy, peanuts, and nuts were detected in less than 5% of patients. At 2-6 months of age, sensitization was found in 36.4%, and after 6 months in 57.9% (p=0.08). In the group with FA before 6 months of age (n=8), 7 patients were sensitized to egg and 6 to milk. The prevalence of milk and egg allergy did not differ between exclusively breastfed and formula-fed children. Hypersensitivity to allergens was found in 4 of 10 breastfeeding patients, for compared to 3 of 11 exclusive formula-feeding patients (p=0.66). Acute allergic reactions were reported in 6.3% of patients with AD, which was 12.2% of children with FA. Triggers were egg (n=5) and fish (n=4). Anaphylaxis did not occur until 6 months of age. The frequency of severe reactions was about the same in children 1st and 2nd years of age (p=0.64). SPT urticaria size, defined in points (max=4), did not differ between children 2-24 months of age. Egg and nut allergens showed the maximum skin reaction: medians were 3 [2; 4] and 1.5 [0.75; 2.5] points. Milk allergens caused significantly less reaction compared with egg (p<0.01). These differences were absent when comparing reactions to individual milk serum fraction proteins and reactions to egg. Hypersensitivity to non-food allergens was found in 41.5% of children with FA (21.5% of children with AD), mainly sensitization to cat epithelium, birch, house dust and dog epithelium was detected. Conclusion. Sensitization to milk proteins and eggs is the leading since 2 months of age, without differences in relation to the age of the infant and the type of feeding. In all cases of moderate AD, SCT is applicable in children 0-2 years of age, with practically no age restrictions.