Non-allergic rhinitis refers to a chronic inflammatory condition of the nasal mucosa characterized primarily by symptoms such as nasal congestion, rhinorrhea, and sneezing. It is not mediated by Type I hypersensitivity reactions and primarily includes eosinophilic non-allergic rhinitis and vasomotor rhinitis. Together with allergic rhinitis, these conditions are collectively referred to as hyperreactive nasal mucosal diseases. However, allergen testing results for these patients are negative. The differential diagnosis for these conditions can be referenced in the first section of this chapter. This section focuses on vasomotor rhinitis.
Vasomotor rhinitis, also known as vasodilatory rhinitis, is a neurogenic inflammation of the nasal mucosa predominantly mediated by neurotransmitters and induced by non-specific stimulation.
Pathogenesis
It is generally considered to result from autonomic nervous system dysfunction, such as increased reactivity of the parasympathetic nervous system. In recent years, growing evidence has supported the role of neuropeptides released from sensory nerve endings in the nasal mucosa in triggering neurogenic inflammation. Neuropeptides released during an axon reflex not only amplify the stimulus signal but also increase vascular permeability, enhance glandular secretion, and even induce mast cell degranulation, leading to histamine release and severe allergy-like inflammatory responses. Furthermore, physical factors (e.g., temperature changes, sunlight), chemical factors (e.g., exposure to volatile irritant gases), and psychological factors (e.g., emotional changes) may also trigger non-immune-mediated histamine release.
Clinical Manifestations
The condition may occur in individuals of any gender but is more commonly observed in middle-aged and young adult females. Environmental factors, such as temperature changes, air pressure fluctuations, or exposure to irritant gases, can provoke nasal symptoms. Common symptoms include nasal congestion, rhinorrhea, sneezing, and nasal itching, although certain symptoms may dominate in some cases, such as rhinorrhea or nasal congestion. The disease occurs perennially and is not associated with common allergens or seasonal pollen exposure.
Examinations
The nasal mucosa, particularly the inferior turbinate mucosa, often presents with edema and congestion, similar to what is observed in allergic rhinitis. Watery or mucous nasal secretions may also be retained within the nasal cavity.
Diagnosis
There are no specific diagnostic methods, and the condition is primarily diagnosed through exclusion. A detailed medical history is required to understand the patient's emotional state, environmental factors, and the time of symptom onset. The potential influence of endocrine factors and certain medications also needs to be considered. The following points can serve as reference criteria:
The condition shows no clear association with common allergens but is linked to certain triggers, including temperature changes, emotional fluctuations, and exposure to irritant gases, leading to symptoms such as sneezing, rhinorrhea, or nasal congestion.
Allergen test results are negative.
Infectious, drug-induced, and structural rhinitis (e.g., deviated nasal septum) are excluded.
Nasal secretion smears and peripheral blood tests do not show elevated eosinophil levels.
Treatment
A comprehensive treatment strategy is utilized, comprising the avoidance of triggers, pharmacological therapy, and surgical interventions.
Pharmacological Therapy
This includes:
- Intranasal corticosteroids
- Antihistamines
- Intranasal anticholinergic agents
- Nasal decongestants (may be used for nasal congestion for no more than seven days)
- Saline nasal irrigation
The choice and combination of medications depend on individual clinical symptom profiles. For instance, intranasal corticosteroids are preferred for patients with predominant nasal congestion, whereas anticholinergic medications are more suitable for those with rhinorrhea as the main symptom.
Surgical Treatment
Surgical interventions are considered for patients who do not respond adequately to or derive limited benefit from medications. The goal of surgery is to relieve nasal congestion and reduce symptoms such as sneezing and rhinorrhea. Procedures targeting nasal congestion include inferior turbinate surgery. For patients whose predominant symptoms are sneezing and rhinorrhea, nasal parasympathetic nerve resection procedures, such as vidian nerve section, are recommended.