title: Allergic rhinitis phenotypes based on bronchial hyperreactivity to methacholine.
abstract: BACKGROUND
  Allergic rhinitis (AR) and asthma may be associated, bronchial hyperreactivity (BHR) is quite common in AR patients. Methacholine (MCH) is a stimulus able to elicit BHR, as many other ones. Phenotyping AR is an up-to-date issue.
  
  
  OBJECTIVE
  The aim of this study was to evaluate whether MCH bronchial challenge is able to differentiate patients with AR.
  
  
  METHODS
  A total of 298 patients (277 males, mean age 28.9 years), suffering from AR were evaluated. Sensitization, rhinitis duration, values for bronchial function (forced vital capacity [FVC], forced expiratory volume [FEV]1, forced expiratory flow [FEF]25-75, and FEV1/FVC ratio), MCH bronchial challenge, visual analog scale (VAS) for nasal and bronchial symptoms perception, and fractioned exhaled nitric oxide (FeNO) were evaluated.
  
  
  RESULTS
  BHR-positive patients (22.8%) had significantly more frequent mite allergy (p = 0.025), longer AR duration (p < 0.001), lower FEV1 (p = 0.003), FEV1/FVC (p < 0.001), FEF25-75 (p < 0.001), higher (p < 0.001), and higher VAS values for both nasal and bronchial symptoms (p < 0.001 for both) in comparison with BHR-negative patients. FeNO can be considered a good predictor for BHR in AR patients (area under the curve, 0.90) with 27.0 ppb as cutoff.
  
  
  CONCLUSIONS
  The present study demonstrates that BHR to MCH could define two distinct phenotypes in AR patients. It could be clinically relevant as BHR-positive patients have initial impairment of lung function, impaired FeNO values, and worsening of respiratory symptoms perception.
authors.affiliation: 1Istituto di Ricovero e Cura a Carattere Scientifico-Azienda Ospedaliera Universitaria San Martino, Genoa, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Ciprandi
authors.forename: Fabio Luigi Massimo
authors.initials: FL
authors.lastname: Ricciardolo
authors.forename: Irene
authors.initials: I
authors.lastname: Schiavetti
authors.forename: Ignazio
authors.initials: I
authors.lastname: Cirillo
mesh_terms: D000328:Adult; D039741:Antigens, Dermatophagoides / Q000276:immunology; D015415:Biomarkers / Q000378:metabolism; D016535:Bronchial Hyperreactivity / Q000175:diagnosis* / Q000276:immunology; D001985:Bronchial Provocation Tests / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride / Q000008:administration & dosage; D009569:Nitric Oxide / Q000378:metabolism; D010465:Perception; D010641:Phenotype; D011237:Predictive Value of Tests; D011379:Prognosis; D012129:Respiratory Function Tests; D065631:Rhinitis, Allergic / Q000175:diagnosis* / Q000276:immunology; D064232:Visual Analog Scale
chemical_list: D039741:Antigens, Dermatophagoides; D015415:Biomarkers; D016210:Methacholine Chloride; D009569:Nitric Oxide