title: Enhanced cough response to hyperpnea with cold air challenge in chronic cough patients showing increased cough sensitivity to inhaled capsaicin.
abstract: BACKGROUND
  Although many chronic cough patients have complained of an induced cough by cold air contact, the clinical relevance of cold air to inducing a cough and the diagnostic value of a hyperpnea with cold air (HCA) challenge to detect a hyperreactive cough reflex have not yet been investigated.
  
  
  METHODS
  Recordings of cough counts after a 2-min HCA challenge were performed in 49 chronic cough patients and 15 healthy controls. Capsaicin cough provocation tests, which determine the threshold concentration of capsaicin that induces five or more consecutive coughs (C5), were also administered.
  
  
  RESULTS
  After comparing the results from the capsaicin cough provocation tests of the patients and the controls, the chronic cough patients were divided into two groups: an increased cough sensitivity (ICS) group (n = 28) (C5 < 32 micromol/l) and a normal cough sensitivity (NCS) group (n = 21) (C5 >or= 32 micromol/l). The median value of induced cough counts after a HCA challenge was 11 coughs in patients with ICS and was a significantly enhanced cough response compared to that of the patients with NCS and healthy controls (four coughs, respectively).
  
  
  CONCLUSIONS
  A simple cough provocation test using a HCA challenge may be useful for detecting ICS. It also suggests that hyperreactive cough reflexes may be one of the mechanisms of inducing chronic cough.
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Medicine, Asan Medical Center, University of Ulsan, Seoul, South Korea.
authors.forename: Y S
authors.initials: YS
authors.lastname: Cho
authors.forename: S Y
authors.initials: SY
authors.lastname: Park
authors.forename: C-K
authors.initials: CK
authors.lastname: Lee
authors.forename: E Y
authors.initials: EY
authors.lastname: Lee
authors.forename: J-H
authors.initials: JH
authors.lastname: Shin
authors.forename: B
authors.initials: B
authors.lastname: Yoo
authors.forename: H-B
authors.initials: HB
authors.lastname: Moon
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000388:Air; D002211:Capsaicin / Q000008:administration & dosage; D016022:Case-Control Studies; D002908:Chronic Disease; D003080:Cold Temperature; D003371:Cough / Q000139:chemically induced / Q000209:etiology*; D004198:Disease Susceptibility; D005260:Female; D006801:Humans; D006985:Hyperventilation / Q000150:complications*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results
chemical_list: D002211:Capsaicin