What is the hallmark of asthma?

The hallmark of asthma is reversible airflow obstruction. Asthma is characterized by bronchial hyperresponsiveness, leading to inflammation and narrowing of the airways, which can cause difficulty in breathing. A key feature of asthma is that this airflow obstruction is not permanent; it can be reversed either spontaneously or with the use of bronchodilators. This reversibility differentiates asthma from other respiratory disorders, like chronic obstructive pulmonary disease (COPD), where airflow obstruction is typically progressive and not fully reversible.

The mechanisms underlying asthma involve airway inflammation and smooth muscle tightening, which can be alleviated with appropriate medical interventions, making reversible airflow obstruction a defining characteristic. Understanding this concept is crucial for proper management and treatment of asthma, which includes the use of inhalers and other therapeutic agents designed to open the airways and reduce inflammation.