Postinfectious cough affects a significant portion of adults following a respiratory infection, with symptoms lasting between 3 and 8 weeks. The inflammatory response triggered by the preceding infection leads to increased bronchial sensitivity and mucus production, while reducing mucus clearance.
Diagnosis of postinfectious cough involves the exclusion of other subacute cough mimics such as asthma, chronic obstructive pulmonary disease (COPD), gastroesophageal reflux disease, or angiotensin-converting enzyme inhibitor use, and the presence of a preceding respiratory infection. Pertussis should be considered in patients with specific symptoms such as a paroxysmal cough, post-tussive vomiting, and inspiratory whoop.
Red flags indicating the need for further investigations include hemoptysis, systemic symptoms, dysphagia, excessive dyspnea, hoarseness, a history of recurrent pneumonia, or prolonged smoking. Coughs lasting longer than 8 weeks are considered chronic and require additional assessment, such as a pulmonary function test to rule out asthma or COPD.
Pharmacologic treatment for postinfectious cough lacks evidence of benefit and is associated with potential harms. Systematic reviews of randomized controlled trials have shown no evidence to support the use of inhaled corticosteroids, bronchodilators, or oral agents. Most trials have indicated that cough symptoms tend to improve without medication, highlighting the self-limiting nature of postinfectious cough. Additionally, the use of pressurized metered-dose inhalers emits powerful greenhouse gases, and off-label use of inhalers can strain the medical supply chain.
Reassuring patients about the time-limited and self-resolving nature of postinfectious cough is crucial in reducing unnecessary prescriptions, including antibiotics. Clinicians should advise patients to schedule a follow-up appointment if their cough persists beyond 8 weeks or if new symptoms develop.
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Competing interests: None declared. This article has been peer reviewed and is distributed in accordance with the terms of the Creative Commons Attribution (CC BY-NC-ND 4.0) license.
