Upper airway cough syndrome (UACS), formerly known as postnasal drip syndrome, is one of the most common causes of chronic cough. It encompasses a spectrum of upper airway disorders, including allergic rhinitis, nonallergic rhinitis, and chronic rhinosinusitis which stimulate cough through mucosal inflammation and upper airway hypersensitivity. This article reviews the pathophysiology, diagnostic evaluation, and management of UACS from an otolaryngologic perspective. The lack of a clear diagnostic test requires clinical differentiation from other causes of chronic cough. Evidence-based treatment strategies aim to resolve cough through targeted control of airway inflammation and mucus production.

Cough is one of the most common symptoms among children. While most acute cough episodes are viral and resolve within 4 weeks, chronic cough persisting beyond 4 weeks warrants further evaluation. Pediatric-specific cough guidelines emphasizing algorithmic evaluation assist in early and accurate diagnosis for preventing long-term pulmonary complications. This article reviews evidence-based approaches to evaluating and managing acute and chronic cough in children, highlighting key diagnostic strategies and targeted treatment options.

Occupational and environmental exposures contribute to a significant, yet often underrecognized, proportion of chronic cough cases. Airway irritants activate sensory neurons through transient receptor potential ion channels, inducing peripheral and central sensitization that persists beyond the exposure period. Common triggers include isocyanates, dusts, fumes, and air pollutants found across diverse industries. Despite recommendations for routine exposure assessment, systematic evaluation remains uncommon in clinical practice. Accurate recognition necessitates detailed exposure histories, temporal correlation with symptoms, and multidisciplinary collaboration, thereby enabling targeted interventions and workplace protections.

This article outlines a comprehensive approach to diagnosing and managing chronic cough in dogs and cats. It emphasizes the importance of thorough history and physical examination, alongside consideration of signalment, to enable prioritization of differential diagnoses. Diagnostic tools including radiography, computed tomography, fluoroscopy, bronchoscopy, and airway sampling are commonly integrated for definitive diagnosis. Treatment can proceed absent a definitive diagnosis; commonly used drug classes in the treatment of chronic cough in dogs and cats include antimicrobials, anti-inflammatories, bronchodilators, and anti-tussives. Nonpharmacologic strategies are also vital. Treatment can effectively control signs and improve quality of life, even where complete resolution is not achievable.

Individuals with classic asthma can present with wheezing, dyspnea, chest tightness, and/or cough. Notably, cough can be the main or only symptom of asthma, termed cough variant asthma. Although there are numerous guidelines for asthma, the diagnosis and management of cough in asthma remain challenging because of its complex physiology. By definition, cough variant asthma excludes individuals with normal airway sensitivity to methacholine (MCh). However, many individuals with chronic cough who are being evaluated for possible cough variant asthma have normal airway sensitivity, yet cough during MCh challenge test (termed COUGH). Despite normal airway sensitivity, individuals with COUGH develop small airway obstruction, dynamic hyperinflation, and gas trapping. The clinical importance of COUGH remains to be determined, but it may be a distinct airway disease phenotype. Previous studies examining pathophysiological differences between classic asthma, cough variant asthma, and COUGH have concluded that differences may lie in individuals' sensitivity to MCh and the degree of bronchodilation and bronchoprotection obtained from deep inspirations. These observations were made exclusively using MCh challenges; however, indirect inhalation challenges (eg, mannitol, hypertonic saline, and eucapneic voluntary hyperventilation) have greater specificity for asthma and may reveal additional pathophysiological distinctions between classic asthma, cough variant asthma, and COUGH. This review highlights opportunities to gain insight into the related airway phenotypes of classic asthma, cough variant asthma, and COUGH by examining impulse oscillometry measurements and the degree of bronchodilation and bronchoprotection from deep inspirations using indirect inhalation challenges, including eucapneic voluntary hyperventilation, hypertonic saline, and mannitol.

Forensic breath alcohol testing depends on contamination-free breath sampling. This case study describes two subjects with a history of gastro-oesophageal reflux disease (GERD) and other aerodigestive symptoms who exhibited repeated coughing near the time of breath alcohol testing. Breath alcohol expirograms demonstrated negative slopes consistent with mouth alcohol contamination. The observations raise the possibility that microaspiration may represent a source of such contamination, and the cases are presented as hypothesis-generating. Further research is needed to evaluate GERD-related microaspiration in the context of breath alcohol testing.