Absence of nasal priming as measured by rhinitis symptom scores of ragweed allergic patients during seasonal exposure to ragweed pollen.

A priming effect, increasing responsiveness of the nasal mucosa as measured by nasal patency or resistance, has been reported to occur after nasal challenge on successive days. Because it has been suggested that the priming effect may be of clinical importance, we have studied whether such an effect occurs during natural pollen exposure as measured by symptom-medication scores in 29 patients with ragweed rhinitis. By Wilcoxon's signed rank test, we compared the symptom-medication scores of patients during two 7-day periods, one early in the season and one later, in which the weekly pollen count was approximately 250 grains/m3; we also compared an early and late period during which the weekly pollen count was approximately 500 grains/m3. There were no statistically significant differences in scores between early and late seasonal periods at the same pollen count. We conclude that the priming effect is not a clinically significant phenomenon during natural pollen exposure in allergic rhinitis patients.