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- Nonallergic rhinitis (NAR) is a syndrome composed of relapsing and remitting nasal congestion, rhinorrhea, postnasal drainage, and/or sneezing.
- Symptoms range from mild to severe and can be classified as inflammatory or noninflammatory.
- Inflammatory form is associated with increased eosinophils, mast cells, or inflammatory markers.
- Noninflammatory form may be caused by abnormality in the autonomic nervous system.
- Diagnosis is one of exclusion.
- Most often misdiagnosed as allergic rhinitis with significant symptom overlap, although NAR is not caused by systemic IgE cascade
- Synonym(s): vasomotor rhinitis; idiopathic rhinitis; nonallergic rhinopathy; intrinsic rhinitis; noninfectious rhinitis
True incidence is difficult to assess given significant overlap with allergic rhinitis, although is estimated to affect 15 to 30 million Americans annually.
NAR and allergic rhinitis affect 10–20% of the population in industrialized countries.
Etiology and Pathophysiology
- Exact mechanism is poorly understood.
- Proposed models include mucosal hyperresponsiveness and autonomic dysregulation leading to increasing glandular secretions and mucosal vasodilation.
- Localized IgE production in nasal mucosa is detected in some studies despite negative serum IgE, making it responsive to similar treatments used in allergic rhinitis (1)[C].
- Underlying triggers include the following:
- Alterations in physical environment including barometric pressure and temperature
- Inhaled chemical triggers such as perfumes, cigarette smoke, and cleaning products
- Medications (rhinitis medicamentosa), especially overuse of OTC decongestant nasal sprays that leads to rebound nasal congestion and medication dependence
- Hormonal changes (i.e., rhinitis of pregnancy, hypothyroidism, acromegaly, etc.)
- Laryngopharyngeal reflux can cause postnasal irritation and increased mucus production.
- Food, especially hot or spicy (gustatory rhinitis)
- Atrophy from age-related changes
- Emotion related
- More common in women than in men
- Presents later in life than allergic rhinitis, 70% after age 20 years while allergic rhinitis often presents in childhood
Avoidance of known triggers such as:
- Cigarette smoke
- Strong scents (perfumes, scented wax, etc.)
- Chemicals/cleaning products
- Fluctuations in temperature/humidity
- Spicy foods
Commonly Associated Conditions
- Allergic rhinitis (common)
- Asthma (common)
- Obstructive sleep apnea (common)