title: Optical rhinometry in nonallergic irritant rhinitis: a capsaicin challenge study.
abstract: BACKGROUND
  Patients with nonallergic irritant rhinitis (NAIR) have symptoms of nasal congestion, nasal irritation, rhinorrhea, and sneezing in response to nasal irritants. We currently have no reliable objective means to quantify these patients' subjective symptoms. In this study, we used the transient receptor potential vanilloid receptor (TRPV1) receptor agonist, capsaicin, as an intranasal challenge while comparing the changes in blood flow with optical rhinometry between subjects with NAIR and healthy controls (HCs).
  
  
  METHODS
  Six HCs and 6 NAIR subjects were challenged intranasally with saline solution followed by increasing concentrations of capsaicin (0.005 mM, 0.05 mM, and 0.5 mM) at 15-minute intervals. We recorded maximum optical density (OD) and numeric analog scores (NAS) for nasal congestion, nasal irritation, rhinorrhea, and sneezing for each subject after each challenge. Correlations between NAS and maximum OD were calculated.
  
  
  RESULTS
  Maximum OD increased with increasing concentrations of intranasal capsaicin in NAIR subjects. There were significant differences in maximum OD obtained for 0.05 mM and 0.5 mM capsaicin between NAIR subjects and HCs. Significant differences were found in the NAS for nasal irritation at 0.005 mM, 0.05 mM, and 0.5 mM, and nasal congestion at 0.5 mM. Correlation between maximum OD and mean NAS was most significant for 0.05 mM capsaicin.
  
  
  CONCLUSIONS
  Optical rhinometry with intranasal capsaicin challenge could prove a viable option in the diagnosis of NAIR. Further studies will investigate its use to monitor a patient's response to pharmacologic therapy and provide further information about the underlying mechanisms of NAIR.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery and Texas Sinus Institute, University of Texas Medical School at Houston, Houston, TX.
authors.forename: Elton M
authors.initials: EM
authors.lastname: Lambert
authors.forename: Chirag B
authors.initials: CB
authors.lastname: Patel
authors.forename: Samer
authors.initials: S
authors.lastname: Fakhri
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Citardi
authors.forename: Amber
authors.initials: A
authors.lastname: Luong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D002211:Capsaicin; D003948:Diagnostic Techniques, Respiratory System; D005260:Female; D006801:Humans; D007509:Irritants; D008297:Male; D008875:Middle Aged; D009666:Nose / Q000098:blood supply; D055095:Optics and Photonics; D012221:Rhinitis, Allergic, Perennial / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D007509:Irritants; D002211:Capsaicin
keywords: acoustic rhinometry; capsaicin; nasal provocation test; nonallergic rhinitis; optical rhinometry