Introduction: Post-nasal drip syndrome (PNDS) is quoted as a common cause of chronic cough. However, there is little evidence to explain the mechanism by which PNDS may stimulate the cough reflex. This cohort study looks at patients with purulent nasal secretions, who may best represent any potential candidate for PNDS, and observes the frequency of symptomatic coughing.
Methods: One-hundred and eight consecutive patients referred to a rhinology clinic with symptoms of chronic infective rhinosinusitis, all with purulent nasal secretions identified on nasendoscopy, were observed through investigation and treatment. Patients were initially treated with broad-spectrum antibiotics and nasal douching. The frequency of coughing was recorded pre- and post- treatment.
Results: Eighty-nine percent of patients complained of post-nasal secretions. Twenty-three (21%) patients complained of cough. Eight had co-existing asthma, 3 had bronchiectasis, 1 had sarcoid and 2 had had a recent respiratory tract infection. Therefore 9 patients (8%) had purulent nasal secretions and a cough with no other discernable pathology. Cough improved in 8 of the 9 patients following treatment. Cough improved in 9 of the 14 patients with other possible co-existing causes for cough.
Conclusions: Only a small proportion of patients with purulent rhinosinusitis without coexisting chest disease complain of cough. Although nasal disease may be a genuine cause for chronic cough it is unlikely to be as common a cause as has been reported. Postnasal secretions do not appear to be an adequate cause for cough and the term 'PNDS' should be replaced by rhinosinusitis when nasal disease is the cause of chronic cough.