[How to approach a chronic cough].

Cough is the most common symptom for which patients seek medical attention. Chronic cough is defined when the symptom lasts for more than 8 weeks. It significantly alters quality of life. Chronic cough may be the dominant symptom which reveals a large number of diseases, not only respiratory. It is classic to distinguish chronic cough according to the chest X Ray results. In case of normal chest X ray, which is the most frequent condition, the diagnosis of tobacco-associated chronic bronchitis, drug induced cough, asthma, oesophageal reflux and rhinosinusitis should be considered. It is, however, not rare that no clear aetiology can be found, thereby defining the concept of idiopathic refractory cough. This paper describes the case of an asthma revealed by a persistent cough that responded well to treatment. It also deals with the new pharmacological pathways that are tested in idiopathic refractory cough.