Intranasal capsaicin is efficacious in nonallergic, noninfectious perennial rhinitis. a placebo-controlled study

The pathophysiology of nonallergic, noninfectious perennial rhinitis (NANIPR) is unknown, but may involve inflammatory mediator release, or neurogenic mechanisms, or both. Previous studies have shown that repetitive use of capsaicin, the pungent agent in hot peppers, reduces nasal symptoms in patients with chronic rhinosinusitis or rhinitis medicamentosa. This reduction is accompanied by a decrease in positive immunoreactivity to calcitonin gene-related peptide in nasal biopsies, consistent with the observation that capsaicin induces neuropeptide depletion and specific degeneration of sensory C fibers in the nasal mucosa of rodents. Although studies have suggested that capsaicin treatment may be efficacious in the treatment of NANIPR, no placebo-controlled studies have been done. Thirty-five adult patients with chronic rhinitis symptoms, which could not be attributed to allergies, infection, anatomic disorders, or hormonal disorders, were randomly assigned to treatment with placebo or capsaicin in a double-blind fashion. All patients were treated first with the application of a long-acting topical nasal decongestant followed by a local anesthetic which was also topically applied. This was followed by a spray of either capsaicin or saline. Patients received seven treatments over a 14-day period, and were followed for nine months. At every visit, subjects rated nasal symptoms since the last visit on a visual analog scale, and a daily symptom record was kept at baseline during therapy and until 2 weeks after treatment. The visual analog scale rated the severity of symptoms, while the daily symptom record rated the duration of symptoms. Nasal lavage was performed at screening, immediately after capsaicin treatment, and at various intervals during follow-up. Lavage fluid was analyzed for leukotrienes C4, D4, and E4, prostaglandin D2, and tryptase. The application of xylocaine spray in the nasal airway was immediately followed by a painful sensation that was described by all patients as "most unpleasant." The nose and lips were protected by petrolatum which effectively prevented any irritation. There was no significant difference in nasal blockage, rhinorrhea, sneezing, or combined symptoms following treatment as scored by the daily record of symptom scores. The visual analog scale scores showed a significant improvement over time in the treated patients that persisted for 9 months. There were no significant changes in any of the mediators in nasal lavage in either group. This study shows that seven capsaicin treatments over a 14-day period ameliorates the symptoms of NANIPR for up to 9 months. This study also suggests that the nonadrenergic, noncholinergic nervous system is involved in the pathophysiology of NANIPR. The study has limitations, however. The authors fail to describe how other causes of perennial rhinitis were ruled out. They also did not evaluate individual symptoms in the visual analog scale, only the overall severity of nasal symptoms. The lack of response in the daily symptom record suggests that the patients continued to have symptoms, but the visual analog scale changes suggest that the symptoms were less severe in the treated patients. It would have also been helpful to know how many of these patients had primarily clear rhinorrhea, and whether this treatment was more effective in treating rhinorrhea or nasal congestion. The symptoms of nasal congestion and posterior nasal discharge in patients with NANIPR continue to be difficult to manage, and new therapies are desperately needed. This study needs to be repeated with another topical anesthetic, and better discrimination of symptom response.