[Definitions of asthma, assessment of disease severity and control]

The definitions of asthma are numerous, often descriptive and non evidences based. They have been used in the clinic to suspect, diagnose a condition which remains in 2011, more a syndrome than a disease. Acute severity, control and severity are current concepts to be used to evaluate a given patient at a given time. They should be better defined and understood to be used more appropriately. At present, these notions are often interchangeable in the literature, used without precisions and no real benefit for the patients and physicians. In the present review, we try to clarify the wording of definitions to be used in the daily practice including difficult asthma. Control of asthma is related to recent daily symptoms and exacerbations; it represents the ultimate goal of treatments according to current guidelines. Acute severe asthma represents the highest point of a severe exacerbation requiring a standardized management in emergency. Chronic severity refers to a longer period of time including the importance of the treatment to maintain a good or optimal control, as well as future risks. It is more linked to the natural history representing a marker of a persistent chronic disease.