ABSTRACT
One of the first nasal challenge tests with a nonspecific agent was carried out by van Lier in 1960 (1). He challenged allergic subjects with veratrine, a mixture of plant alkaloids, in and outside the pollen season and observed a shift in doseresponse curve, thereby concluding that patients with allergic rhinitis became more responsive to veratrine during the pollen season. This observation represents a phenomenon known as nasal hyperresponsiveness or nasal hyperreactivity. Hyperreactivity or hyperresponsiveness in the upper and lower airways refers to an increased sensitivity to nonspecific stimuli or irritants. In the case of hyperreactivity of the nasal mucosa, the most prominent symptoms of rhinitis patients are sneezes, rhinorrhea, and nasal blockage on exposure to low doses of stimuli, which do not induce symptoms in healthy subjects.
