Asthma-II: Pathophysiology and Classification

Asthma involves airway inflammation and increased sensitivity, often caused by allergens and irritants.

When an individual is exposed to allergens, the body activates immune cells—including mast cells, macrophages, eosinophils, neutrophils, T and B lymphocytes, and airway epithelial cells—leading to chronic inflammation.

This triggers the production of allergen-specific IgE antibodies that attach to mast cells. Upon repeated exposure, allergens bind to IgE on mast cells, releasing inflammatory mediators such as histamine , cytokines, leukotrienes, and prostaglandins.

These mediators recruit eosinophils, lymphocytes, and neutrophils, causing bronchoconstriction, vascular congestion, edema, and mucus secretion, all contributing to airway obstruction.

Asthma involves nerve-related changes in the airways, which, when triggered by allergens or irritants, lead to increased muscle contraction, mucus secretion, and airway narrowing.

Persistent inflammation can cause airway remodeling, including fibrosis, muscle hypertrophy, mucus hypersecretion, inflammation, and angiogenesis.