title: Chronic cough and irritable larynx.
abstract: BACKGROUND
  Perennial rhinitis (PR), chronic rhinosinusitis (CRS), or both, asthma, and gastroesophageal reflux disease (GERD) are the most frequent triggers of chronic cough (CC). Extrathoracic airway receptors might be involved in all 3 conditions because asthma is often associated with PR/CRS and gastroesophageal refluxate might reach the upper airway. We previously found that most patients with rhinosinusitis, postnasal drip, and pharyngolaryngitis show laryngeal hyperresponsiveness (LHR; ie, vocal cord adduction on histamine challenge) that is consistent with an irritable larynx.
  
  
  OBJECTIVE
  We sought to evaluate the role of LHR in patients with CC.
  
  
  METHODS
  LHR and bronchial hyperresponsiveness (BHR) to histamine were assessed in 372 patients with CC and in 52 asthmatic control subjects without cough (asthma/CC-). In 172 patients the challenge was repeated after treatment for the underlying cause of cough.
  
  
  RESULTS
  The primary trigger of CC was PR/CRS in 208 (56%) patients, asthma in 41 (11%) patients (asthma/CC+), GERD in 62 (17%) patients, and unexplained chronic cough (UNEX) in 61 (16%) patients. LHR prevalence was 76% in patients with PR/CRS, 77% in patients with GERD, 66% in patients with UNEX, 93% in asthma/CC+ patients, and 11% in asthma/CC- patients. Upper airway disease was found in most (95%) asthma/CC+ patients and in 6% of asthma/CC- patients. BHR discriminated asthmatic patients and atopy discriminated patients with PR/CRS from patients with GERD and UNEX. Absence of LHR discriminated asthmatic patients without cough. After treatment, LHR resolved in 63% of the patients and improved in 11%, and BHR resolved in 57% and improved in 18%.
  
  
  CONCLUSIONS
  An irritable larynx is common in patients with CC and indicates upper airway involvement, whether from rhinitis/sinusitis, gastric reflux, or idiopathic sensory neuropathy.
authors.affiliation: Department of Clinical Pathophysiology, University of Turin, Turin, Italy. caterina.bucca@unito.it
authors.forename: Caterina B
authors.initials: CB
authors.lastname: Bucca
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Bugiani
authors.forename: Beatrice
authors.initials: B
authors.lastname: Culla
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Guida
authors.forename: Enrico
authors.initials: E
authors.lastname: Heffler
authors.forename: Sabrina
authors.initials: S
authors.lastname: Mietta
authors.forename: Antonella
authors.initials: A
authors.lastname: Moretto
authors.forename: Giovanni
authors.initials: G
authors.lastname: Rolla
authors.forename: Luisa
authors.initials: L
authors.lastname: Brussino
mesh_terms: D000328:Adult; D016535:Bronchial Hyperreactivity / Q000150:complications; D002908:Chronic Disease; D003371:Cough / Q000209:etiology*; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications; D006801:Humans; D007818:Laryngeal Diseases / Q000150:complications*; D008297:Male; D012372:ROC Curve; D012220:Rhinitis / Q000150:complications; D012852:Sinusitis / Q000150:complications; D013577:Syndrome