Chronic cough: a rational approach to investigation and management.

C hronic cough is a common problem: community surveys suggest a prevalence of recurrent cough of up to 40% and persistent cough of up to 10% [1–3]. Approximately 10% of new patients seen in respiratory clinics are referred with an isolated chronic cough [4]. Most patients referred for a specialist opinion are nonsmokers with normal findings on basic screening investigations, such as chest radiograph, serial peak expiratory flow measurements and spirometry. Females account for 60–70%, and many report a long-standing cough, which started at around the time of the menopause [5]. The current evaluation of chronic cough is based on the ‘‘anatomic, diagnostic’’ protocol originally described by IRWIN et al. [6] .20 yrs ago. This investigation protocol is based on the view that most cases of nonasthmatic chronic cough are caused by rhinosinusitus and/or gastrooesophageal reflux [6, 7]. The investigation protocol remains largely based on expert opinion, and there is a lack of evidence from randomised, double-blind, placebo-controlled trials supporting central tenants of the anatomic, diagnostic protocol [8, 9]. Nevertheless, there are multiple reports of the successful management of cohorts of patients with chronic cough using variants of the anatomic, diagnostic approach to investigation, and the protocol has largely stood the test of time [10]. Despite this, many clinicians view chronic cough as a difficult clinical problem [11]. Amongst the most significant problems is the difficulty in knowing how far to take investigations in patients who commonly report a long-standing cough, which, although distressing, is not obviously progressive.