After nasal allergen challenge, substance P and CGRP are released into nasal secretions of atopic patients . In allergic rhinitis patients, but not in normal control subjects, exogenous substance P induces nasal obstruction.
In contrast, CGRP instillation in the nasal cavity increased nasal blood flow and caused the sensation of nasal obstruction, but had no immediate effects on albumin leakage or glandular secretion. Nerve growth factor has been found in nasal lavage fluid and also in cells, particularly mast cells, in allergic rhinitis resulting nose inflammation
There is evidence for the participation of nasal nerves in aspects of the LPR. Most studies have reported that the number of sneezes during the LPR, although much less than the EPR, is elevated compared with appropriate controls . When a localized, unilateral nasal allergen challenge is performed, ipsilateral and contralateral elevations in airway resistance, as well as in levels of histamine, IL-4, IL-8, and airways secretions are seen.
Although it is not possible to refute the hypothesis that local allergen application may lead to systemic contralateral effects unrelated to neurogenic inflammation, there is evidence that stimulation of local sensory nerves with capsaicin can lead to dose-dependent leukocyte influx, albumin leakage, and glandular secretion. This all lead to nose inflammation
