Evaluation of the nasal response to histamine provocation with acoustic rhinometry

The objectives of this study were to evaluate the reproducibility of the nasal response to histamine with the acoustic rhinometer and to compare the responses in normal and rhinitic subjects. Our study comprised 10 normal and 10 rhinitic subjects. Each subject had six sessions of provocation: three with histamine phosphate at a concentration of 4 mg/mL and three with saline phosphate provocation. Basal measurements of the nasal volumes were taken initially and then at 5-minute intervals for 90 minutes. All rhinometric measurements were made bilaterally and in triplicate. The variation between the triplicate measurements (2% +/- 0.1% [95% CI]) and the variation between the basal measurements (7.3% +/- 3.1% [95% CI]) were very low in both normal and rhinitic subjects. The comparison of the average congestive response of the normal subjects revealed that they responded steadily for at least 90 minutes to histamine and saline but that the response to histamine was significantly more important. There was also a low variability in the congestive response between the subjects. The comparison of the average congestive response of the rhinitic subjects revealed that their responses were more dynamic, not steady, compared with those of the normal subjects. The response was statistically significant only in the first few intervals. The comparison of the average congestive response to saline suggests that rhinitic subjects present a more important response than normal subjects. The comparison of the average congestive response to histamine between rhinitic and normal subjects was not statistically different but was different in the shape of the response pattern. Acoustic rhinometry is a highly reproducible method for measuring nasal volume in our provocation protocol. Histamine nasal provocation leads to a pattern of congestive response that is different in normal and rhinitic subjects. Histamine nasal provocation seems to be useful in addition to the study of nasal hyperreactivity and, as such, could permit differentiation between rhinitic and nonrhinitic subjects.