These guidelines incorporate the recent advances in chronic cough pathophysiology, diagnosis and treatment. The concept of cough hypersensitivity has allowed an umbrella term that explains the exquisite sensitivity of patients to external stimuli such a cold air, perfumes, smoke and bleach. Thus, adults with chronic cough now have a firm physical explanation for their symptoms based on vagal afferent hypersensitivity. Different treatable traits exist with cough variant asthma (CVA)/eosinophilic bronchitis responding to anti-inflammatory treatment and non-acid reflux being treated with promotility agents rather the anti-acid drugs. An alternative antitussive strategy is to reduce hypersensitivity by neuromodulation. Low-dose morphine is highly effective in a subset of patients with cough resistant to other treatments. Gabapentin and pregabalin are also advocated, but in clinical experience they are limited by adverse events. Perhaps the most promising future developments in pharmacotherapy are drugs which tackle neuronal hypersensitivity by blocking excitability of afferent nerves by inhibiting targets such as the ATP receptor (P2X3). Finally, cough suppression therapy when performed by competent practitioners can be highly effective. Children are not small adults and a pursuit of an underlying cause for cough is advocated. Thus, in toddlers, inhalation of a foreign body is common. Persistent bacterial bronchitis is a common and previously unrecognised cause of wet cough in children. Antibiotics (drug, dose and duration need to be determined) can be curative. A paediatric-specific algorithm should be used.

The American College of Chest Physicians (ACCP) and the European Respiratory Society (ERS)^{5, 6} have each endorsed their own set of guidelines on the management of cough; however, criticism⁷ of their content and breadth suggest the need for further concise recommendations. The British Thoracic Society guidelines cover not only chronic cough but also acute cough and the organisational issues of cough clinics. International differences in delivery of respiratory health care and management strategies support the notion that such guidelines would be desirable. The British Thoracic Society Standards of Care Committee agreed to the development of a Working Group tasked with the job of producing a set of guidelines for the management of cough with the following key objectives:

Fig. 1.— Overview of the evaluation of chronic cough in an adult. ACE-I: angiotensin converting enzyme inhibitor; PEF: peak expiratory flow; PNDS: post-nasal drip syndrome; GORD: gastro-oesophageal reflux disease. Fig. 2.— Therapeutic algorithm. ACE: angiotensin-converting enzyme; GORD: gastro-oesophageal reflux disease. Fig. 3.— Investigational algorithm. CT: computed tomography. Fig. 4.— Diagnostic algorithm for the approach to children with chronic cough. ENT: ear, nose and throat; PFT: pulmonary function testing; BAL: bronchoalveolar lavage; CT: computed tomography; tbc: total blood count; CMV: cytomegalovirus; PCR: polymerase chain reaction; MRI: magnetic resonance imaging; NO: nitric oxide; BHR: bronchial hyperresponsiveness. CONTENTS Chronic cough, here defined as a cough of >8 weeks duration, is a common and frequently debilitating symptom 1, 2 that is often viewed as an intractable problem. However, theexperience of specialist cough clinics is that a very high success rate, in the order of 90%, can be achieved (table 1⇓) 3–15. The key to successful management is to establish a diagnosis and to treat the cause of cough. Truly idiopathic cough is rare and misdiagnosis common, particularly because of the failure to recognise that cough is often provoked from sites outside the airway. These guidelines aim to distil the lessons from these reports and provide a framework for a logical care pathway for patients with this highly disabling symptom. View this table: Table 1— Commonest causes of chronic cough in patients investigated in specialist clinics There are three common causes of chronic cough that arise from three different anatomical areas. This varied presentation explains the major reason for the success of multidisciplinary cough clinics compared with general clinics 16. As asthma, reflux and rhinitis are the realms of different specialists who have little experience in the diagnosis of conditions outside their expertise, a patient with chronic cough may not undergo full evaluation. This problem is exacerbated by the frequently atypical presentation of …

In 2011, a European Respiratory Society Task Force embarked on a process to determine the position and clinical relevance of the cough hypersensitivity syndrome, a disorder characterised by troublesome coughing often triggered by low levels of thermal, mechanical or chemical exposure, in the management of patients with chronic cough. A 21-component questionnaire was developed by an iterative process supported by a literature review. 44 key opinion leaders in respiratory medicine were selected and interviewed as to their opinions.There was a high degree of unanimity in the responses obtained, with all opinion leaders supporting the concept of cough hypersensitivity as a clinically useful paradigm. The classic stratification of cough into asthmatic, rhinitic and reflux-related phenotypes was supported. Significant disparity of opinion was seen in the response to two questions concerning the therapy of chronic cough. First, the role of acid suppression in reflux cough was questioned. Secondly, the opinion leaders were split as to whether a trial of oral steroids was indicated to establish a diagnosis of eosinophilic cough.The cough hypersensitivity syndrome was clearly endorsed by the opinion leaders as a valid and useful concept. They considered that support of patients with chronic cough was inadequate and the Task Force recommends that further work is urgently required in this neglected area.

Rationale: Cough is the most common complaint for which medical attention is sought, and chronic cough can be both physically and mentally debilitating. There is currently no evidence supporting the use of antitussives in chronic treatment-resistant cough. Objectives: We tested the hypothesis that morphine sulfate in the dose of 5 mg twice daily would bring about a reduction in cough frequency and severity in patients failing to respond to specific measures. Methods: Patients recruited from the Hull Cough Clinic were enrolled into a randomized double-blind placebo-controlled study using 4 weeks of slow-release morphine sulfate and a corresponding period of matched placebo. An open-labeled extension of the core study allowed dose escalation to 10 mg twice daily. Cough was assessed using the Leicester Cough Questionnaire, daily symptom diary, and citric acid cough challenge. Results: Twenty-seven patients completed the core study. A significant improvement of 3.2 points over baseline was noted on the Leicester Cough Questionnaire (p < 0.01). A rapid and highly significant reduction by 40% in daily cough scores was noted among patients on slow-release morphine sulfate (p < 0.01). Objective testing of the cough reflex using citric acid cough challenge tests did not show any significant changes. Eighteen patients continued into the extension study. Two-thirds of these patients opted to increase the morphine to 10 mg twice daily. At the end of 3 months, there was a similar improvement in cough between the 5- and 10-mg groups. Conclusion: Morphine sulfate is an effective antitussive in intractable chronic cough at the doses of 5 to 10 mg twice daily.