No generally accepted definition of asthma exacerbation is thus far available, though in 2012 an expert committee endorsed by the National Institute of Health proposed such definition as ''a worsening of asthma requiring the use of systemic corticosteroids to prevent a serious outcome''. Graham and Eid reviewed the impact of asthma exacerbations, and noted that, analysing the outcomes with existing treatments, many patients with asthma remain symptomatic and experience exacerbations. This requires the introduction of new strategies to more effectively reduce the exacerbation risk, based on correct diagnosis, stopping smoking, correct inhaler technique, consistent adherence, weight management, and gaining control with the addition of medication''. Indeed, as allergic asthma is the most common form, a specific approach by allergen immunotherapy should receive more attention. Actually, the efficacy of immunotherapy in allergic asthma, by the subcutaneous or the sublingual route, is supported by robust meta-analyses. The most important allergen source causing asthma is the house dust mite, but an increasing role for molds is apparent due to the ongoing climate change.Thus far, there is no generally accepted definition of asthma exacerbation. In 2012, an expert committee endorsed by the National Institute of Health (NIH) reviewed all the available literature and found no dominant definition of exacerbation. The most widely used definitions included three components, all related to treatment rather than symptoms, based on systemic use of corticosteroids, asthma-specific emergency department visits or hospitalization, and use of short-acting b-agonists (SABAs) as quick-relief medications, respectively. The working group participants proposed that the definition of 'asthma exacerbation' be ''a worsening of asthma requiring the use of systemic corticosteroids to prevent a serious outcome''. As core outcomes, they proposed inclusion and separate reporting of several essential variables of an exacerbation and the development of a standardized, component-based definition of 'exacerbation' with clear thresholds of severity for each component 1 . In addition, it was suggested that the term 'exacerbation' should be distinguished from the terms 'not well controlled asthma' or 'uncontrolled asthma', which are measures of chronic disease activity. Indeed, according to the Global Initiative on Asthma (GINA) ''Poor asthma control itself substantially increases the risk of exacerbations. However, several additional independent risk factors have been identified, i.e. factors that, when present, increase the patient's risk of exacerbation even if symptoms are few'' 2 . The article by Graham and Eid in the present issue reviews the impact of asthma exacerbations, and the current and future treatment strategies to establish asthma control and reduce the risk of future exacerbations 3 . The authors analyse the outcomes with existing treatments, concluding that many patients ! 2015