A heterogeneous disease characterized by chronic airway inflammation that results in recurrent episodes of wheezing, shortness of breath (SOB), chest tightness and cough that vary over time and in intensity, with variable expiratory airflow limitation
Epidemiology
Affects approximately 300 million people worldwide, causing around 1,000 deaths per day
Signs and Symptoms
Symptoms are usually associated with airflow obstruction, which is often reversible either spontaneously or with treatment
Tend to have >1 type of respiratory symptom, intermittent, variable, worse at night or upon waking, and provoked by triggers (eg exercise, allergens, irritant exposure, weather changes, drugs or viral respiratory infections)
Types of Asthma
Asthma phenotypes (clusters of asthma characteristics) differ in clinical manifestations, pathophysiology and demographic location of the patient
Allergic asthma: Present in childhood, with a positive family history of asthma, and previous history of allergy (eg eczema, food allergy, allergic rhinitis, etc)
Non-allergic asthma: Asthma without an allergic component
Late-onset asthma: Also called adult-onset; asthma presenting and diagnosed for the first time in adult years
Asthma with fixed airflow limitation: Airway wall remodeling due to chronic airway inflammation causing irreversible airflow obstruction
Asthma with obesity: Prevalence of symptomatic asthma is increased in those suffering from obesity
Cough variant asthma and cough predominant asthma: Cough may be the only initial asthma symptom and evidence of variable airflow present only during bronchial provocation testing, subsequent wheezing and responsiveness to bronchodilator may develop, responsive to inhaled corticosteroid-containing treatment
