CME review article This feature is supported in part by an educational grant from AstraZeneca LP Taming chronic cough Matthew A. Rank, MD*; Pramod Kelkar, MD†; and John J. Oppenheimer, MD‡ Objective: To review the available evidence on treating chronic cough to relay a thoughtful, evidence-based approach for the diagnosis and treatment of chronic cough. Data Sources: MEDLINE, PubMed, EMBASE, and CINAHL were searched using the following keywords: cough, asthma, gastroesophageal reflux, sinusitis, rhinitis (allergic, seasonal), postnasal drip, vocal cord dysfunction, lung disease (interstitial), bronchiectasis, and bronchoscopy. Study Selection: Studies were selected based on their relevance to the diagnosis and treatment of chronic cough. Because of a lack of randomized prospective studies, nonrandomized and retrospective studies were considered, with their strengths and limitations noted. Results: Few randomized controlled trials have addressed the diagnosis and treatment of chronic cough. There are several prospective noncontrolled trials for adults with chronic cough that found a high percentage of cough resolution when using an approach that focused on the diagnosis and treatment of the most common causes: asthma, gastroesophageal reflux disease, and upper airway cough syndrome. Preliminary studies in children support an approach that distinguishes between a wet and dry cough, as well as an in-depth investigation of any specific symptoms that point to an underlying chronic illness. Conclusion: Allergists, as experts in treating upper airway and lower airway disorders, are uniquely poised to diagnose and treat chronic cough. Ann Allergy Asthma Immunol. 2007;98:305–313. Off-label disclosure: Drs Rank, Kelkar, and Oppenheimer have indicated that this article does not include the discussion of unapproved/investigative use of a commercial product/device. Financial disclosure: Drs Kelkar and Oppenheimer have indicated that in the last 12 months they have been on the Consultant/Speakers’ Bureau for Merck, GSK, Astra-Zeneca, Schering, Pfizer, UCB, Abbott, Wyeth, Greer, and Aventis. Instructions for CME credit 1. Read the CME review article in this issue carefully and complete the activity by answering the self-assessment examination questions on the form on page 314. 2. To receive CME credit, complete the entire form and submit it to the ACAAI office within 1 year after receipt of this issue of the Annals. INTRODUCTION Chronic cough (lasting longer than 8 weeks in adults and 4 weeks in children) is a common (10% to 20% of adults) and debilitating ailment. 1 Cough has an important physiologic role in the human body’s defense system, because it results in clearing of excess secretions and foreign bodies from the airway. However, in some patients cough may be excessive and unnecessary and may lead to a general deterioration in their quality of life. 2 Patients seek medical attention for their cough for a variety of reasons, chief among them is to receive reassurance that nothing is seriously wrong (Table 1). 2 A more recent prospective survey study of patients with chronic cough found the most prevalent problems from a patient’s perspective were frustration, irritability, anger, frequent phy- sician visits and testing, and sleep disturbances. 3 Vagus nerve fibers have been shown, in animal models, to terminate along the tracheobronchial tree. 4 The subtype of vagus nerve fibers (C-fiber, rapidly adapting receptors, or other fiber type) and the relative contribution of vagus nerve fibers to provoking a cough response in the brainstem are areas of ongoing research. 4 Following the anatomy of the vagus nerve offers a logical approach to explore the differ- ential diagnosis of chronic cough. A diagnostic workup of chronic cough, termed the anatomic, diagnostic protocol, has been studied prospectively (not randomized or blinded) and offers a framework for many of the published diagnostic algorithms. 5 By following this pathway, Irwin and col- leagues 5 have demonstrated successful treatment of chronic cough in 84% to 98% of patients. Other published results * Division of Allergic Diseases, Mayo Clinic, Rochester, Minnesota. † Allergy & Asthma Care, PA, Maple Grove, Minnesota. ‡ Division of Allergy and Immunology, UMDNJ-New Jersey Medical School, Cedar Knolls, New Jersey. Received for publication November 27, 2006. Received in revised form January 1, 2007. Accepted for publication January 16, 2007. VOLUME 98, APRIL, 2007 305