The term idiopathic rhinitis (IR) is used in this study to describe a patient group with following characteristics: patients with complaints of nasal obstruction, sneezing and/or rhinorrhea for a period of over 1 year, which cannot be attributed to allergy, nasal or paranasal infection, anatomical disorders, pregnancy or lactation and/or systemic disorders. These patients are non-smokers and do not use medication affecting nasal function. They have no beneficial effect of intranasal steroid spray (INS) treatment.

The population incidence of IR is estimated to be as high as 10%. The pathophysiology of IR is largely unknown. Several hypotheses have been put forward. In general it is assumed that neurogenic mechanisms play an important role. Neuropeptides like CGRP, SP, NKA/B, NPY, NGF are released from afferent neurons in the nasal mucosa after activation by unspecific stimuli and can be responsible for the symptoms of IR.

For this group of IR-patients, there is until now only one treatment option: intranasal capsaicin application. Capsaicin, the pungent agent in hot pepper, is supposed to exert its' therapeutic effect via degeneration or desensitization effect on the afferent C-fibers.

The hypothesis is that nasal capsaicin treatment reduces neurogenic inflammation and reduces in that way nasal symptoms.

Inclusion Criteria:

1. Patients with persistent (> 12w) rhinological symptoms: nasal discharge, sneezing, congestion for an average of at least 1 h per day for at least 5 days during a period of 14 days, negative skin prick test or negative RAST, and without structural abnormalities explaining nasal obstruction will be proposed to participate in the trial.
2. Age > 18 and < 50 years
3. Written informed consent
4. Willingness to adhere to visit schedules
5. Adequate contraceptive precautions in female patients with childbearing potential
6. Unresponsiveness to nasal steroid spray (4 weeks of use)

Exclusion Criteria:

1. Age < 18 and > 50 years
2. Patients with AR, demonstrated by either positive skin prick test or RAST
3. Presence of IgE in nasal lavage fluid
4. Structural abnormalities: nasal polyps, severe septal deviation (septum reaching concha inferior or lateral nasal wall.
5. Systemic steroid treatment less than 4 weeks before the inclusion in the study.
6. Nasal steroid spray less than 4 weeks before the inclusion, oral leukotriene antagonists or long-acting antihistamines less than 2 weeks before the inclusion.
7. Inability of the patient to stop taking medication affecting nasal function.
8. Evidence of infectious rhinitis/rhinosinusitis.
9. Pregnancy or breastfeeding.
10. Any disorder of which might compromise the ability of a patient to give truly informed consent for participation in this study.
11. Enrollment in other investigational drug trial(s) or is receiving other investigational agent(s) for any other medical condition.
12. Contra-indications for local anaesthesia (Cocaïne 5%).
13. Smoking.
14. Systemic disease with lesions in ENT domain.
15. Malignancies or severe comorbidity.