Bronchial asthma is a chronic inflammatory airway disorder characterized by variable airflow limitation and heterogeneous immunological pathways. Recent developments in molecular immunology, biomarker-oriented diagnostics, and biologic therapies have redefined asthma as a complex set of phenotypes and endotypes rather than a single disease entity. This extended review explores the multifactorial pathogenesis of asthma, including genetic susceptibility, epithelial barrier dysfunction, type-2 and non–type-2 inflammatory pathways, microbiome alteration, and environmental risk factors.

Bronchial asthma; airway inflammation; type-2 asthma; non-type-2 asthma; microbiome; FeNO; spirometry; biologic therapy; digital inhalers; precision medicine; environmental triggers; airway remodeling.

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