[Dyspnoea in asthma: diagnostic approach].

Dyspnoea is a cardinal symptom of asthma and an essential part of assessing control of the disease. Its intensity is variable for the same level of bronchial obstruction, which suggests the involvement of other mechanisms. Therefore, it is extremely important to characterize and measure dyspnoea in asthmatic patients because its profile can be quantitatively and qualitatively modified by disease control, comorbidities and anxiety. Hence the value of using additional tools to ACT and ACQ because the latter do not characterize nor measure specifically dyspnoea in asthma. Different tools can be used in this regard, at rest as the subjective assessment of dyspnoea by scales such as the modified Medical Research Council (mMRC), the New York Heart Association (NYHA) and the Visual Analogue Scale (VAS) or more recently using the Dyspnea-12 and the Multidimensional Dyspnea Profile (MDP) questionnaire, which assesses the sensory and affective dimensions of dyspnoea; and during exercise testing such as the "modified" Borg scale, graduated from 0 to 10, or the VAS. Among the factors contributing to dyspnoea in asthmatic patients, probably bronchial obstruction, increased airway resistance and dynamic hyperinflation play an important role. Despite this, the asthmatic patient's description of dyspnoea may be masked by hyperventilation syndrome or other comorbidities that can easily be detected and treated through educational programs and targeted therapies.