Features of hereditary allergic history in different phenotypes of bronchial asthma in children under 5 years of age

Rationale. In pediatric practice, phenotypes of bronchial asthma (BA) defined by comorbid allergic diseases — atopic dermatitis (AtD) and allergic rhinitis (AR) — are of particular importance. Their combination in a single patient indicates a systemic nature of inflammation and likely a higher genetic predisposition. However, the contribution of heredity to the formation of different BA phenotypes in preschool children remains insufficiently studied. Objective: to evaluate the frequency and structure of hereditary allergic history burden in different BA phenotypes in children under 5 years of age. Materials and methods. A retrospective cohort study was conducted involving 493 children aged 3–5 years with BA and 200 control children. Four groups were formed based on phenotype: isolated BA (n = 128), BA with AtD (n = 130), BA with AR (n = 122), BA with AtD and AR (n = 113). Family history of allergy was analyzed with calculation of odds ratios (OR) and 95% confidence intervals (CI). The χ² test with Yates’ correction was used for frequency comparisons. Results. A positive hereditary history was found in 66,7% of children with BA compared to 19,5% in the control group (OR = 8,28; p < 0,001). The frequency of family history of allergy increased with the number of comorbid allergic diseases: isolated BA — 53.9% (OR = 4,83; p < 0,001), BA+AR — 55,7% (OR = 5,20; p < 0,001), BA+AtD — 70,8% (OR = 10,00; p < 0,001), BA+AtD+AR — 88,5% (OR = 31,76; p < 0,001). The BA+AtD+AR phenotype significantly exceeded other groups in the frequency of inheritance through both parental lines (31,0% vs. 5,5–13,1% in other phenotypes; p < 0,001 for all comparisons). The highest maternal inheritance rates were found in the BA+AtD phenotype (37,7%; OR = 5,16; p < 0,001), while the highest paternal inheritance rates were in BA+AtD+AR (25,7%; OR = 3,97; p < 0,001). Conclusion. BA phenotypes in children under 5 years of age with multiple comorbid allergic pathologies, especially those including the combination of AtD and AR, have the most pronounced genetic determination. The greatest family history of allergy is characteristic of the BA+AtD+AR phenotype, confirming the role of accumulation of atopic diseases as a marker of high genetic predisposition.