OBJECTIVE Optical rhinometry is a new method that quantifies light extinction in optical density to assess nasal blood volume as a measure of nasal patency. The purpose of this study is to evaluate optical rhinometry as an objective evaluation of nasal patency using nasal provocation testing with histamine and oxymetazoline. METHODS Prospective pilot. METHODS Academic tertiary rhinologic practice. METHODS Convenience sample of five adult subjects with allergic rhinitis and five adult normal subjects who underwent challenge with histamine and oxymetazoline. Patients underwent challenge with increasing concentrations of histamine to determine the amount of histamine needed to cause a positive optical rhinometry reading. The same subjects then underwent histamine challenge with this amount followed by oxymetazoline. Nasal patency was assessed subjectively after each challenge with the visual analog scale. RESULTS The median histamine amount needed to cause a positive response was statistically lower in allergic rhinitis as compared with nonallergic subjects at 150 microg and 300 microg, respectively (P = 0.04). When comparing the optical rhinometry with subjective nasal congestion after histamine and oxymetazoline challenges, there was a statistically significant correlation with r = 0.79 (P = 0.00003). CONCLUSIONS This initial study demonstrates a correlation between subjective symptoms of nasal patency and objective measurements with the optical rhinometer. Less histamine amount necessary to incite nasal congestion in allergic rhinitis suggests that these patients may be primed to the effects of histamine. These preliminary data suggest that optical rhinometry is able to assess changes in nasal patency during challenges with histamine and oxymetazoline.