D1.48 - Early-Onset Multiorgan Allergic Phenotype with Transformation into Controlled Asthma in a 2-Year-Old Child: The Role of Molecular Diagnostics (ALEX²) in Risk Stratification

The classic "atopic march" often begins with atopic dermatitis (AD) and food allergy, progressing to respiratory allergic diseases. Cases of early (before 3 years of age) transformation into persistent bronchial asthma (BA) responsive to inhaled corticosteroids (ICS) are of particular interest for studying predictors and management. Molecular diagnostics is a key tool for assessing the risk of severe reactions and differentiating syndromes.

A 2-year-old girl. Family history is positive for atopy in both parents. Disease onset at 3 months of age: AD, history of cow's milk protein-induced proctocolitis, confirmed IgE-dependent hen's egg allergy (urticaria, Gal d 1 >100 kUA/L). At 1.5 years of age, seasonal allergic rhinoconjunctivitis (ARC) developed. From the age of 2, typical BA symptoms appeared: multitriggered (physical activity, emotions, aeroallergens) episodes of wheezing and coughing, including during the birch pollen season. Infectious and anatomical causes were ruled out. Baseline therapy with inhaled fluticasone (100-200 mcg/day) was initiated, achieving complete symptom control over 3 months. The therapy and symptom complex meet the diagnostic criteria for "Allergic, Persistent Bronchial Asthma", step 3 therapy for children under 5 years (GINA 2025). An episode of anaphylaxis (urticaria, bronchoconstriction) to nut traces was recorded. Molecular testing (ALEX²) revealed polysensitization: to Bet v 1 (35.8 kUA/L) and other aeroallergens, epidermal allergens (Can f 1 - 30.57 kUA/L), as well as sensitization to stable nut and peanut storage proteins (2S albumins, 11S globulins) and ovomucoid (Gal d 1 - 27.27 kUA/L).

Discussion and Conclusions: This case demonstrates the rapid development of a severe multiorgan allergic phenotype. Transcutaneous sensitization through a damaged skin barrier in AD is the probable route for the formation of IgE to food allergens (nuts, peanuts) with which the child had no oral contact, increasing the risk of systemic reactions upon first intake. The diagnosis of ВА at 2 years of age is valid given the characteristic multitriggered symptoms, response to ICS therapy, and atopic background, underscoring the need for active diagnosis.The molecular profile stratifies risk: sensitization to ovomucoid (Gal d 1) and nut storage proteins (2S/11S) predicts persistent food allergy and a high risk of anaphylaxis, while Bet v 1-associated oral allergy syndrome has a favorable prognosis.