When asthma diagnosis becomes a challenge.

Asthma is a worldwide disease affecting an estimated 300 million individuals [1, 2]. Some authors refer to the increased prevalence of asthma reported during the past decades, in many parts of the world, as a wave of ‘‘asthma epidemic’’ [3]. Given the recent increase in asthma-related healthcare costs [4], it has become important, in a time of economical restriction, to critically review the dimensions of this phenomenon and to investigate the underlying causes. First of all, is there a real epidemic threat? Indeed, besides several proposed explanations for increasing asthma preva- lence (e.g. exposure to tobacco smoke, air pollution and specific allergens, change in diet intake, obesity, exposure to infections and microbial substance in the environment) [3], there has also been an improved awareness of the disease over the past few years. Substantial effort has been made in the past decade for the development and the dissemination of international asthma guidelines. Such widespread publicity has certainly contributed to improve asthma management worldwide and to identify and treat new asthmatic patients. However, it might also have caused overdiagnosis of asthma and, more specifi- cally, it may have contributed to the increased proportion of incorrectly diagnosed asthma cases. Inevitably, any misdiag- nosed cases lead to over treatment or inappropriate treatments [5], and increased risk of side-effects in the absence of any pharmacological benefit