Improvement of symptoms of non-allergic chronic rhinitis by local treatment with capsaicin.
Sixteen adult patients suffering from severe chronic non-allergic rhinitis with nasal vasoconstrictor abuse for more than a year, received, under local anaesthesia, an intranasal spray of capsaicin (3.3 x 10(-3) mol), the pungent agent in hot pepper, once weekly for 5 weeks. The subjective intensity of their nasal obstruction, rhinorrhoea and sneezing frequency were evaluated throughout the study and the vascular effects of capsaicin on the nasal mucosa were recorded by anterior rhinomanometry and laser Doppler flowmetry. Calcitonin gene-related peptide (CGRP) is a vasodilator agent present in sensory nerves and may play a major role in the vascular component of neurogenic inflammation. Therefore, the nasal mucosa content of CGRP-like immunoreactivity (CGRP-LI) was determined by radioimmunoassay in biopsies obtained before and after the capsaicin treatment. Intra-nasal capsaicin application evoked a larger vascular response in patients with rhinitis than in controls (P less than 0.05). Both nasal vascular responses and subjective discomfort following capsaicin were markedly reduced after the fifth application (P less than 0.01). In parallel, a 50% reduction of the CGRP-LI content in the nasal biopsies was observed. All symptoms were significantly improved throughout a 6 month follow-up period. No significant side-effects occurred and weaning from nasal vasoconstrictor agents was possible. Both the subjective symptom score and objective measurements of vascular reactivity suggest that repeated intra-nasal capsaicin application could be beneficial for patients with chronic rhinitis, possibly by reducing hyperreactive nasal reflexes.