title: Cough triggers and their  pathophysiology in patients with prolonged or chronic cough.
abstract: BACKGROUND
  The character or timing of chronic cough is considered to be unpredictable for diagnosing its cause. However, the associations of cough triggers with cough pathophysiology remains unknown.
  
  
  METHODS
  We developed a closed questionnaire listing 18 triggers that were reported by ≥1% of 213 patients in a retrospective survey. Using this questionnaire, patients with cough-predominant or cough-variant asthma (n = 140) and those with non-asthmatic cough (54) were asked whether their cough was induced by the listed triggers. Associations of triggers with causes of cough, airway sensitivity to inhaled methacholine, exhaled nitric oxide (NO) levels, number of sensitizing allergens, and scores from gastroesophageal reflux (GER) questionnaires were examined. Factor analysis was used to categorize variables, including the 12 most common cough triggers, diagnosis of asthmatic cough, airway sensitivity, and exhaled NO levels.
  
  
  RESULTS
  "Cold air" and "fatigue/stress" induced cough more often in asthmatic coughers than in non-asthmatic coughers. "Spices" and "meals" induced cough more frequently in GER-coughers (n = 19). Patients who marked "cold air" as the trigger were more sensitive to inhaled methacholine and showed higher exhaled NO levels than those who did not mark this trigger. The "post-nasal drip" trigger was associated with elevated exhaled NO levels, and this association was mainly exhibited by patients with cough-predominant asthma. The triggers "pollen" and "mold smell" were associated with a number of sensitizing allergens. The number of triggers was weakly associated with GER scores. By factor analysis, "cold air," "fatigue/stress," asthmatic cough, airway hypersensitivity, and elevated NO levels were categorized into the same factor.
  
  
  CONCLUSIONS
  Several cough triggers may reflect the pathophysiology of prolonged or chronic cough.
authors.affiliation: Department of Respiratory Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan. hmatsumo@kuhp.kyoto−u.ac.jp
authors.forename: Hisako
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Rollin P
authors.initials: RP
authors.lastname: Tabuena
authors.forename: Akio
authors.initials: A
authors.lastname: Niimi
authors.forename: Hideki
authors.initials: H
authors.lastname: Inoue
authors.forename: Isao
authors.initials: I
authors.lastname: Ito
authors.forename: Masafumi
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: Kojiro
authors.initials: K
authors.lastname: Otsuka
authors.forename: Tomoshi
authors.initials: T
authors.lastname: Takeda
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Oguma
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nakaji
authors.forename: Tomoko
authors.initials: T
authors.lastname: Tajiri
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Iwata
authors.forename: Tadao
authors.initials: T
authors.lastname: Nagasaki
authors.forename: Makiko
authors.initials: M
authors.lastname: Jinnai
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Matsuoka
authors.forename: Michiaki
authors.initials: M
authors.lastname: Mishima
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D003371:Cough / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D008875:Middle Aged; D013147:Spirometry; D011795:Surveys and Questionnaires
chemical_list: D007073:Immunoglobulin E