13 Evaluation of nasal obstruction during natural grass pollen (GP) exposure and nasal histamine provocation (NHP)

Abstract

GRASS POLLEN (GP) EXPOSURE AND NASAL HISTAMINE PROVOCATION (NHP). B. Asman, M.D., S. Stool, M.D., D. Respler, M.D. and P. Fireman, M.D., Pittsburgh, Pennsylvania The purpose of this study was to evaluate changes in nasal obstruction during natural GP exposure and NHP using nasal conductance (CN) and nasal airway area (NA). Two groups of subjects were studied. Group 1 consisted of 5 nonatopic subjects evaluated before and after NHP with increasing doses of histamine (0.05 mg to 10 mg). Group 2 consisted of 9 GP sensitive subjects (positive history and intradermal skin tests at 100 PNU) evaluated just before then weekly during GP season (May-July). Weekly average GP counts were obtained. Computer assisted posterior rhinomanometry measured CN. Using a video linked rigid rhinoscope placed at a standardized location anterior to the margin of the inferior turbinate, NA was determined by computer digitization of video images. To reduce the effect of nasal cycling, CN and NA were expressed as bilateral CN and NA. Results were expressed as percentage change from baseline. There were significant correlations between CN and NA in both NHP (r=.80, p<.Ol) and GP exposure (r=.30, p<.Ol). Data analysis for NHP yielded a significant correlation between histamine dose and both CN (r-=-.55, p<.Ol) and NA (r=-.69, p<.Ol). CN and NA did not correlate well with average weekly GP counts. These data indicate that while CN and NA may be used in the evaluation of nasal obstruction induced by NHP, their use in documenting nasal obstruction induced by natural GP exposure is less well supported.