Chronic Cough, a New Disease, Not Just An Old Problem

Chronic cough is defined as a cough persisting for longer than 8 weeks. Chronic cough is common, with an approximate prevalence of 10% of the global population. In Canada, recent estimates indicate that the prevalence of cough is 16% among adults aged 45-85 years. Chronic cough can interrupt work, sleep, and social interactions, making it very troubling for patients, with impacts on physical, social, and psychological health. Cough is one of the leading causes of visits to primary care practitioners. The peak incidence for presentation to primary care is among individuals in the 50-60 years age group and it is twice as frequent in women. Currently, most clinicians address cough as a symptom of other medical conditions, which leads to trials of treatments for diseases that may not be present. This approach can lead to unnecessary costs, frustration for both clinicians and patients, and potential harms from the therapies prescribed. Instead, a diagnostic work up needs to be performed to identify refractory chronic cough as a distinct disease entity, resulting from afferent neuronal hypersensitivity and central nervous system dysfunction. The secondary factors that aggravate chronic cough (smoking, asthma, gastro-esophageal reflux, among others) should be considered as treatable traits associated with the primary disease process rather than only the direct causes of the cough.