Nonallergic rhinitis

Rhinitis is the irritation and swelling of the mucous membrane of the nose. There are two main types: allergic rhinitis and nonallergic rhinitis. Allergic rhinitis is caused by a type 1 hypersensitivity reaction that leads to inflammation of the nasal mucous membranes on exposure to certain allergens (e.g., dust, animal dander, mold spores, or plant pollen). Nonallergic rhinitis does not always involve an inflammatory process, and it includes infectious rhinitis, atrophic rhinitis, vasomotor rhinitis, drug-induced rhinitis, occupational rhinitis, gustatory rhinitis, hormonal rhinitis, and nonallergic rhinitis with eosinophilia syndrome (NARES). Infectious rhinitis is most often secondary to an upper respiratory tract infection that manifests as rhinosinusitis. Clinical manifestations of rhinitis include nasal congestion, rhinorrhea, and postnasal drip. Atrophic rhinitis can be primary (idiopathic) or secondary (e.g., due to granulomatous diseases). This form of rhinitis commonly manifests with a foul-smelling, crust-filled nasal cavity and anosmia. Patients with NARES might present with nasal polyposis and hyposmia. Initial management of allergic rhinitis involves allergen and irritant avoidance and pharmacotherapy with intranasal corticosteroids or oral or intranasal antihistamines. Nasal lavage and surgical procedures can relieve symptoms in patients with atrophic and vasomotor rhinitis.

Allergic rhinitis is covered in detail separately.

• Rhinitis: irritation and swelling of the mucous membrane of the nose
• Allergic rhinitis: acute or chronic rhinitis caused by exposure to an inhaled allergen (e.g., dust, animal dander, mold spores, plant pollen)
• Nonallergic rhinitis: acute or chronic rhinitis syndrome that is not IgE mediated

Apart from infectious rhinitis, nonallergic rhinitis includes the following subtypes.

Both allergic and nonallergic rhinitis manifest with postnasal drainage and nasal congestion. However, nasal itching and sneezing are only seen in allergic rhinitis.

• Definition: chronic rhinitis associated with atrophy and sclerosis of the nasal mucosa
• Etiology
  • Primary atrophic rhinitis (ozaena): an idiopathic condition, which primarily affects middle-aged women in tropical regions (e.g., in India, China, Latin America, the Mediterranean); associated with mucosal colonization with Klebsiella ozaenae ^[3]
  • Secondary atrophic rhinitis occurs following
    • Granulomatous diseases of the nasal cavity
      • Infectious causes include syphilis, leprosy, rhinoscleroma
      • Noninfectious causes include SLE, granulomatosis with polyangiitis
    • Radiotherapy and/or operations involving the nasal cavity
• Clinical features
  • Merciful anosmia: extremely foul-smelling nasal cavity but the patient is unaware of the foul smell (anosmia)
  • Nasal cavity is spacious, lacks turbinates, and is covered in yellowish-green crusts.
  • Epistaxis
• Diagnostics
  • No specific diagnostic test is indicated.
  • Rhinoscopy, nasal cultures, and/or CT scans may be performed to evaluate the extent of the disease.
• Treatment: aims to decrease the size and improve the blood flow of the nasal cavities and to promote regeneration and increase lubrication of the dry nasal mucosa but no form of treatment can completely eliminate the symptoms
  • Removal of nasal crusts
    • Irrigation of the nasal cavity with warm saline
    • Application of 25% glucose in glycerine, antibiotic solutions, and/or estradiol to the wall of the nasal mucosa
    • Systemic antibiotics (e.g., fluoroquinolones, rifampicin, streptomycin)
  • Surgical procedures that decrease the volume of the nasal cavity ^[3]
    • Modified Young's procedure
    • Insertion of Teflon paste, fat, or bone underneath the mucosa of the nasal cavity
    • No randomized clinical trials are available to confirm the efficacy of these measures.

Topical sympathomimetic drugs (e.g., xylometazoline) are contraindicated in atrophic rhinitis since they may decrease vascular perfusion of the nasal cavity and worsen symptoms.

• Definition: : a type of nonallergic rhinitis that is caused by an increase in blood flow to the nasal mucosa
• Etiology ^[4]
  • Most often idiopathic
  • Irritant odors; (e.g., cigarette smoke, perfumes, car exhaust)
  • Temperature change (e.g., cold and dry air, changes in humidity)
  • Certain drugs (e.g., aspirin, NSAIDs, alpha-1 blockers, beta blockers, OCPs)
  • Emotional stimuli (e.g., anxiety, excitement)
• Pathophysiology
  • ↑ Parasympathetic activity: Parasympathetic stimulation causes vasodilatation of blood vessels in the nasal mucosa and increases mucous secretion.
  • ↓ Sympathetic activity: Sympathetic stimulation causes vasoconstriction of the nasal blood vessels.
• Clinical features
  • Sneezing
  • Nasal congestion, rhinorrhea, postnasal drip
  • Hypertrophic turbinates may be seen in chronic vasomotor rhinitis.
• Treatment
  • Address the underlying cause of rhinitis
  • Medical therapy
    • Intranasal instillation of hypertonic NaCl solution
    • Intranasal antihistamines (e.g., azelastine) and/or intranasal glucocorticoids (e.g., fluticasone)
    • Nasal decongestants (e.g., phenylephrine, oxymetazoline)
  • Surgical therapy
    • Resection of hypertrophic nasal turbinates in order to relieve nasal obstruction
    • Endoscopic vidian neurectomy

For more info on nasal polyps, deviated nasal septum, adenoid hypertrophy, and foreign nasal body see their respective articles.

The differential diagnoses listed here are not exhaustive.

• Avoidance of triggers (e.g., medications, tobacco smoke, alcohol)
• Nasal irrigation (e.g., with small amounts of saline solution)
• Intranasal glucocorticoids and/or intranasal antihistamines
• For severe symptoms: oral decongestants (e.g., pseudoephedrine)
• For gustatory rhinitis: nasal ipratropium