Asthma is a heterogenous disorder that is characterized by variable airflow obstruction, airway inflammation and hyperresponsiveness, and reversibility either spontaneously or as a result of treatment. Multiple etiologies no doubt exist for both its inception and symptom exacerbation once the disease is established. Factors underlying inception can range from viral respiratory tract infections in infancy(1,2) to occupational exposures in adults.(3) Factors underlying asthma exacerbations include allergen exposure in sensitized individuals, viral infections, exercise, irritants, ingestion of nonsteroidal anti-inflammatory agents, among others. Exacerbating factors may include one or all of these exposures, and vary both among and within patients. Asthma treatment is determined to a large extent following an initial assessment of severity and subsequent establishment of control, both of which can be variable over time and assessed in two domains: impairment (current) and risk (long term consequences).(4) Unfortunately, despite the availability of effective therapies, suboptimal asthma control exists in many patients on a world-wide basis.(5) The future development of novel therapies and treatment paradigms should address these disparities.