Data collection
Data collected included demographic characteristics, atopic (atopic dermatitis, allergic rhinoconjunctivitis (ARC), IgE-mediated food allergies) and non-atopic (gastroesophageal reflux disease, clinical sleep apnea syndrome or confirmed by polygraphy) comorbidities, the pediatric asthma control test (ACT) score, the number of asthma exacerbations and severe asthma exacerbations (requiring hospital treatment and/or systemic corticosteroid therapy for 3 days or more), the number of days of taking oral corticosteroids for severe exacerbations, and the number of visits to the emergency room or emergency consultations for asthma exacerbations over the past 12 months. Children were categorized into frequent exacerbators (≥ 2 exacerbations per year in the last 12 months) and pauci-exacerbators25. The presence of sensitization to common pneumallergens (house dust mites, cat or dog dander, birch pollen, and grass pollen), defined by specific IgE > 0.1 kU/l or positive prick-tests, plasma eosinophilia, the plasma concentration of total IgE, and the lung function in the previous six months were also recorded.