Definition

Asthma is a chronic inflammatory disorder of the airways in which many cells and cellular elements play a role. The chronic inflammation causes an associated increase in airway hyper-responsiveness that leads to recurrent episodes of wheezing, breathlessness, chest tightness and coughing, particularly at night or in the early morning. These episodes are usually associated with widespread but variable airflow obstruction that is often reversible either spontaneously or with treatment.1 However for use in clinical practice, asthma may be defined as a chronic inflammatory disorder of the airways characterized by recurrent episodes of wheezing, breathlessness, chest tightness and cough that is often reversible either spontaneously or with treatment. Epidemiologically, however asthma may need to be defined differently. Terms like 'current asthma' (prevalence of asthma symptoms in the last 12 months) and 'ever asthma' (prevalence of asthma symptoms anytime in the past or present) may need to be clarified during such a deliberation. The use of ambiguous terms like 'allergic bronchitis', 'asthmatic bronchitis', 'wheezing bronchitis' (etc.) should be avoided. For clinical purposes, classifying asthma as 'atopic and non-atopic', 'allergic and non-allergic' or 'intrinsic and extrinsic' does not alter the management in most patients.