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Rhinitis - Medicine Viva Guide

Definition

Rhinitis is inflammation of the nasal mucosa characterized by one or more of the following: nasal congestion, rhinorrhea (anterior or posterior), sneezing, and nasal itching. It is broadly divided into allergic and non-allergic subtypes.

Classification

TypeKey Features
Allergic Rhinitis (AR)IgE-mediated, seasonal or perennial
Non-allergic (Vasomotor)Profuse clear rhinorrhea, no allergen trigger
Non-allergic with Eosinophilia (NARES)Eosinophils on nasal smear, negative allergy tests
InfectiousViral (most common), bacterial, fungal
Drug-inducedOCP, reserpine, beta-blockers, rhinitis medicamentosa
GranulomatousSarcoidosis, Granulomatosis with Polyangiitis (Wegener's)
HormonalPregnancy, hypothyroidism
AtrophicCrusting, foul smell (ozena)
Mechanical/ObstructiveSeptal deviation, adenoid hypertrophy, foreign body
  • Cummings Otolaryngology Head and Neck Surgery

Allergic Rhinitis (AR) - The Most Important Type

Epidemiology

AR ranks 5th among all chronic diseases in the US in terms of economic impact, with estimated annual direct costs of up to $5 billion. It accounts for ~3.5 million lost workdays per year. About 80% of patients with allergic asthma also suffer from AR, and AR is an independent risk factor for developing asthma.

Classification of AR

  • Seasonal (Hay Fever): Triggered by outdoor allergens - tree pollens (spring), grass pollens (summer/early fall)
  • Perennial: Year-round symptoms - triggered by indoor allergens: house dust mites, cat dander (most common animal allergen), cockroaches, indoor mold
  • Dust mites peak from August to December

Pathophysiology

Pathophysiology of Allergic Rhinitis showing Sensitization (Phase 1) and Clinical Disease (Phase 2) with Early and Late inflammation

Phase 1 - Sensitization

  1. Allergen is deposited on nasal mucosa and taken up by antigen-presenting cells (APCs)
  2. Mucosal epithelial cells secrete TSLP, which matures dendritic cells into TH2-promoting subtypes
  3. TH2 cells drive B cells to produce allergen-specific IgE antibodies
  4. IgE binds to high-affinity receptors (FcεRI) on mast cells and basophils
Key cytokines:
  • IL-4 and IL-13 → Enhanced IgE production
  • IL-5 → Enhanced eosinophil activity and prolonged eosinophil survival
  • IL-9 → Bronchial hyperreactivity

Phase 2 - Early Phase Reaction (within minutes)

On re-exposure, allergen cross-links IgE on mast cells → mast cell degranulation → release of:
  • Preformed mediators: Histamine, tryptase, kinins
  • Newly synthesized: Prostaglandins, leukotrienes, PAF
Results in: sneezing, watery rhinorrhea, nasal itching, congestion (within minutes)

Phase 2 - Late Phase Reaction (4-8 hours later)

Chemoattractants and adhesion molecules (ICAM-1, VCAM-1) recruit inflammatory cells:
  • Eosinophils, basophils, CD4+ lymphocytes, monocytes
  • These cells release a second wave of mediators
  • Nasal congestion dominates the late phase
  • Goldman-Cecil Medicine, p. 2355

Priming Phenomenon

A hallmark of AR - after repeated allergen exposure, the threshold dose to elicit symptoms decreases more than 5-fold by day 4 of consecutive challenges. This explains why patients worsen as the allergy season progresses even when pollen counts fall, and why they become hypersensitive to non-specific irritants (perfume, smoke, cold air).

Clinical Features

Classic Signs ("Allergic Stigmata")

SignDescription
Allergic saluteUpward palm thrust against nose to relieve itching; causes a supratip crease at the junction of upper/lower lateral cartilages
Allergic shinersDark circles under eyes due to venous stasis
Dennie-Morgan linesExtra wrinkle folds under the lower eyelid
Adenoid faciesOpen mouth, high arched palate, long face, retracted jaw - from chronic mouth breathing

Symptoms

  • Paroxysmal sneezing
  • Watery (clear) rhinorrhea
  • Nasal congestion and pruritus
  • Conjunctival and pharyngeal itching
  • Postnasal drip
  • Loss of smell and taste
  • Nasal speech quality

Complications

  • Serous otitis media (1/3 to 1/2 of children with AR) - eustachian tube dysfunction
  • Rhinosinusitis - edematous mucosa obstructs sinus ostia
  • Nasal polyps (pearl-gray gelatinous masses - unusual in uncomplicated AR alone)
  • Sleep disturbance, snoring, sleep apnea-like symptoms
  • Asthma - 80% of asthmatic patients have AR
  • Epistaxis in children (from nose picking due to irritation)
  • Maxillomandibular alignment problems (overbite/underbite) from chronic mouth breathing

Nasal Examination Findings

  • Pale, bluish, edematous inferior turbinates (NOT pathognomonic)
  • Thin, clear secretions
  • No appearance is pathognomonic for AR

Diagnosis

1. History

  • Seasonal pattern, family history of atopy
  • Late-evening or early-morning symptoms suggest dust mite allergy
  • Improvement with change of environment

2. Nasal Smear (Hansel's Stain)

  • Eosinophils support allergic diagnosis but are not diagnostic alone
  • Elevated peripheral eosinophilia may support diagnosis (but can be absent)

3. Skin Prick Testing (SPT) - Gold Standard

  • Allergen applied epicutaneously with a lancet (1 mm depth)
  • Wheal ≥ 3 mm larger than negative control = positive
  • Sensitivity: 80-100%, Specificity: 70-90%
  • Stop antihistamines 2-7 days before testing
  • Contraindications: Severe asthma, history of anaphylaxis, beta-blocker use, pregnancy

4. Serum-Specific IgE (RAST/ImmunoCAP)

  • Less sensitive than SPT for inhalant allergens
  • Useful when SPT is contraindicated

5. Local Allergic Rhinitis (LAR) - Important Concept

A subset of patients have typical AR symptoms but negative skin testing and serum IgE. These patients have a localized nasal IgE response without systemic atopy. Diagnosis by nasal allergen challenge. Prevalence may be 47-62% of patients with perennial symptoms who test negative systemically.

Treatment

Step 1: Environmental Control (Allergen Avoidance)

  • Air conditioning with HEPA filters
  • Impermeable encasings for pillows and mattresses
  • Wash linens in hot water
  • Remove carpets, avoid fans and cool-mist vaporizers
  • Masks with microfoam filters for dust allergy

Step 2: Pharmacotherapy

Drug ClassExamplesKey Notes
Intranasal Corticosteroids (INCS)Fluticasone, mometasone, budesonideMost effective single agent for AR; reduces all nasal symptoms
Oral 2nd-gen AntihistaminesLoratadine, cetirizine, fexofenadine, levocetirizine, desloratadineLess sedating than 1st gen; good for sneezing and rhinorrhea
Intranasal AntihistaminesAzelastine, olopatadineOnset within minutes; may cause bitter taste or mild somnolence
Leukotriene Receptor Antagonists (LTRA)MontelukastUseful especially in AR with concurrent asthma
Topical DecongestantsOxymetazoline, xylometazolineMax 3 days use only - prolonged use causes rhinitis medicamentosa (rebound swelling)
Oral DecongestantsPseudoephedrine, phenylephrineNo rebound, but less effective; side effects: insomnia, HTN, arrhythmias
Intranasal IpratropiumIpratropium bromide sprayTargets rhinorrhea; little effect on congestion
Saline irrigation-Thins secretions, mechanically clears allergens
Rhinitis Medicamentosa - Caused by prolonged use (>3 days) of topical decongestants; leads to rebound mucosal swelling and then chronic mucosal inflammation. Treatment = stop the topical decongestant.

Step 3: Allergen Immunotherapy (AIT) - Disease-Modifying

Two routes:
  • Subcutaneous Immunotherapy (SCIT): Injections started at dilute dose, escalated weekly over months to maintenance, then monthly. Introduced since 1911. Evidence from multiple systematic reviews.
  • Sublingual Immunotherapy (SLIT): Alternative route
Mechanism: Shifts immune response from TH2 to TH1/Treg dominance; IL-10 and Treg cells suppress total and allergen-specific IgE, increase IgG4 ("blocking antibody"), downregulate eosinophil function, decrease mast cell/basophil activation threshold.
Indications: Failed pharmacotherapy, desire for durable benefit, high risk for asthma or new sensitizations.
Contraindications to SCIT: Poorly controlled asthma, active autoimmune disease, malignancy, pregnancy (to initiate; maintenance can continue if pregnancy occurs during treatment).

Non-Allergic Rhinitis

Vasomotor (Idiopathic) Rhinitis

  • Perennial, profuse clear rhinorrhea and congestion
  • No allergen correlation, no eosinophilia
  • Triggers: temperature changes, strong odors, smoke, alcohol, exercise

NARES (Non-Allergic Rhinitis with Eosinophilia Syndrome)

  • Most common in adults
  • Eosinophilia on nasal smear
  • Negative allergy test results for specific allergens
  • Responds to intranasal steroids

Drug-Induced Rhinitis

  • Oral contraceptives, reserpine, hydralazine, beta-blockers (even eye drops), topical decongestants (rhinitis medicamentosa)

Key Viva Points to Remember

  1. Rhinitis medicamentosa = rebound congestion from topical decongestants used >3 days
  2. AR + asthma link: 80% of asthmatic patients have AR; AR is a risk factor for asthma - "one airway, one disease"
  3. Pale, edematous turbinates are characteristic but NOT pathognomonic for AR
  4. Nasal polyps are pearl-gray and gelatinous - unusual in uncomplicated AR alone; their presence should raise suspicion of complicating factors
  5. Skin prick test threshold: wheal ≥3 mm above negative control = positive
  6. Stop antihistamines before skin prick testing (2-7 days depending on half-life)
  7. Pregnancy = contraindication to initiating SCIT, but maintenance can be continued
  8. Local Allergic Rhinitis (LAR) = AR symptoms + negative systemic tests + positive nasal challenge
  9. INCS are the most effective single pharmacological class for AR
  10. 1% to 2% of viral URIs (common colds) progress to bacterial sinusitis

Sources: Cummings Otolaryngology Head and Neck Surgery; Goldman-Cecil Medicine; Textbook of Family Medicine 9e
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