Which disease is characterized by reversible airway obstruction and bronchoconstriction due to inflammation and sensitivity?

• A. COPD
• B. Bronchitis
• C. Pneumonia
• D. Asthma

Answer: (D)

Asthma is defined by inflammation of the airways with increased sensitivity, causing episodic bronchoconstriction and obstruction that is typically reversible, either spontaneously or with bronchodilator therapy. Exposure to triggers like allergens, exercise, cold air, or irritants leads to airway smooth muscle spasm, mucosal edema, and mucus production, narrowing the lumen and producing wheeze, shortness of breath, chest tightness, and cough that can vary over time and often worsen at night. The inflammatory process and airway hyperresponsiveness explain why symptoms flare with triggers and improve with anti-inflammatory and bronchodilator treatment. In contrast, the other conditions described have different patterns: COPD features largely irreversible, progressive obstruction; bronchitis centers on airway inflammation and cough without the characteristic reversible airflow limitation; pneumonia involves infection with consolidation rather than primarily reversible airway narrowing.