Characteristic appearance of the oropharynx in patients with postnasal drip (PND)‐induced cough

Abstract Introduction Post‐nasal drip (PND)‐induced cough is a common cause of chronic cough. However, there is little known about the characteristic physical findings of this condition. Objectives We investigated views of the pharyngeal wall in patients with PND‐induced cough using a handy endoscopic images. Methods The subjects were 135 consecutive patients referred to our hospital with a sensation of something “dripping down the throat” as one of their symptoms. Physical findings for the oropharynx were examined using Wi‐Fi endoscope camera. The difference in probability of symptoms in patients with acute cough and those with subacute/chronic cough was assessed using a Bayesian Fisher exact test on a 2 × 2 table. Results Among the patients, 105 (78%) complained of cough, 78 (58%) of acute cough, 20 (15%) of subacute cough, and 7 (5%) of chronic cough; and 71 (53%) had coexisting asthma. Using Bayesian inference, a sore or scratchy throat and fever were more common in patients with acute cough than in those with subacute/chronic cough. In endoscopic images of the oropharynx, a reddish curtain sign on the posterior pharyngeal wall behind the palatopharyngeal arch was found in 121 patients (90%). Conclusion Patients with acute PND‐induced cough have a component of acute upper respiratory infection, because of high probability of a sore or scratchy throat and fever as symptom. A reddish curtain sign may be a useful finding for identifying PND‐induced cough in these cases.