Chronic cough management: Practical guidelines and PICO-based evidence for screening and investigation

Chronic cough is a common clinical condition requiring comprehensive assessment. This review employs a symptom-focused approach, prioritizing the presenting symptom of "chronic cough" to mirror real-world clinical practice. Ten key questions regarding the investigations in the uncertain areas were systematically addressed based on the PICO framework and applying the GRADE system for evidence synthesis to provide the strength of recommendation and quality of evidence for key questions. Practical diagrams were developed to facilitate clinical decision-making. The initial evaluation involves screening for red flag signs requiring urgent attention, followed by a detailed history-taking and physical examination. A chest radiograph is recommended as the first-line investigation. The primary objective of the initial evaluation is to identify the cause and initiate appropriate treatment. If history and physical examination prove insufficient for a definitive diagnosis, referral to a specialist is advised for further specific testing. The recommendations on specific testing include fractional exhaled nitric oxide for cough variant asthma, nasal endoscopy or digital endoscopy (optional) for upper airway cough syndrome, paranasal sinus computed tomography (CT) for chronic rhinosinusitis, and laryngoscopy for hoarseness. Spirometry is for the diagnosis of obstructive airway diseases, and peak flow variability or bronchial challenge tests are complements particularly if asthma is suspected. Gastroesophageal reflux (GERD) investigations are for patients with chronic cough without typical GERD symptoms. Sinus radiographs and chest CT are not routinely recommended. Our guideline distinguishes itself by prioritizing a symptom-based clinical evaluation to guide clinicians toward the most probable diagnosis, streamlining the diagnostic process.