Low-Dose Capsaicin Nasal Spray Effective for Idiopathic Rhinitis

By Lisa Rappaport

June 12, 2020

(Reuters Health) - A low-dose capsaicin nasal spray that can be self-administered once daily for idiopathic rhinitis works as well as high-dose capsaicin administered over several hours in the hospital with local anesthetic, a new study suggests.

In a randomized, double-blind trial, researchers compared two different concentrations of capsaicin nasal spray (0.01 millimolar and 0.001 mM) self-administered once daily at home as well as the current standard of care for idiopathic rhinitis, five consecutive applications of 0.1 mM capsaicin administered with local anesthetic at one-hour intervals in the hospital.

The patients assigned to standard care received high-dose capsaicin in the hospital with local anesthetic, then were sent home to self-administer a placebo nasal spray for four weeks. The other three treatment groups received placebo applications in the hospital, then were assigned to self-administer a nasal spray with placebo, 0.01 mM capsaicin, or 0.001 mM capsaicin for four weeks.

All 68 patients in the study were asked to report nasal symptoms like rhinorrhea, nasal obstruction, itch and sneezing at a baseline screening visit and again at 4, 12, and 24 weeks.

Compared with placebo, major nasal symptoms were significantly reduced with standard care and with 0.01 mM capsaicin, the researchers report in the Journal of Allergy and Clinical Immunology.

"Home administration of capsaicin nasal spray at the right dosage may alleviate symptoms in a substantial part of non-allergic non-infectious rhinitis patients, and even prevent unnecessary and ineffective nasal surgery," said study coauthor Dr. Peter Hellings of the departments of otorhinolaryngology at the University of Leuven and the University of Ghent, in Belgium, and the University of Amsterdam in The Netherlands.

"The typical profile of patients that respond well to capsaicin nasal spray are those with chronic rhinitis symptoms without known allergies or infections in the nose," Dr. Hellings said by email.

The results may not be applicable in clinical practice because capsaicin nasal spray at the lower doses studied is not commercially available, Dr. Hellings said.

In theory, the lower dose nasal spray would be less painful to administer, eliminating the need for local anesthetic, said study coauthor Dr. Laura Van Gerven of the University Hospital Leuven.

The only specific treatment for non-allergic rhinitis is intranasal capsaicin spray, the pungent agent of chili pepper, which is effective in about 70% of patients, Dr. Van Gerven said by email.

"This spray acts on the afferent nerves in the nose, which are thought to be overreactive/hyperreactive in non-allergic rhinitis patients," Dr. Van Gerven said. "However, the downside of this therapy is that capsaicin binds on the TRPV1 receptor, present on these nerves, which is also a pain receptor, causing the burning sensation when you touch your nose while cutting a chili pepper."

Lowering the dose of capsaicin reduces the burning sensation and removes the need for local anesthetic to reduce pain from administration, Dr. Van Gerven said.

"The patient can apply the spray at home instead of going to the hospital," Dr. Van Gerven added. "It's less time-consuming for the patient and doctor."

SOURCE: https://bit.ly/37jvDwS Journal of Allergy and Clinical Immunology, online May 18, 2020.