Allergic Rhinitis

Allergic Rhinitis - Nose Knows No Peace

• IgE-mediated inflammation of nasal mucous membranes.
• Types: Seasonal (SAR), Perennial (PAR). Classified by ARIA guidelines: Intermittent (<4 days/wk or <4 consecutive wks) vs. Persistent (>4 days/wk & >4 consecutive wks).
• Symptoms: Paroxysmal sneezing, watery rhinorrhea, nasal itching, congestion.
• Signs: Allergic shiners, transverse nasal crease (allergic salute), Dennie-Morgan infraorbital folds.
• Common Indian Triggers: Pollens (e.g., Parthenium), house dust mites, molds, animal dander, cockroach allergens.

⭐ Allergic rhinitis often coexists with asthma and atopic dermatitis, forming the "atopic march" (sequential development of allergic diseases).

Allergic Rhinitis - The IgE Mayhem

• Type I (IgE-mediated) hypersensitivity to aeroallergens (pollen, dust mites). Mast cells & basophils central.
• Pathogenesis:
  • Sensitization: Allergen → Th2 cells → IL-4/IL-13 → B-cells produce IgE → IgE coats mast cells.
  • Elicitation (Re-exposure): Allergen cross-links IgE → mast cell degranulation.
• Mediators & Phases:
  • Early (minutes): Histamine, PGD2, Leukotrienes (LTC4/D4/E4) → acute symptoms.
  • Late (4-8 hrs): Eosinophil influx (via IL-5), cytokines → sustained inflammation, hyperreactivity.
• Core Symptoms: Sneezing, watery rhinorrhea, nasal itching, congestion. Ocular symptoms common.

⭐ Part of the "Atopic March": often coexists/precedes asthma and atopic dermatitis. Risk for asthma development.

Allergic Rhinitis - Symptoms & Stages

• Core Symptoms:
  • Paroxysmal sneezing
  • Watery rhinorrhea (anterior/posterior)
  • Nasal itching
  • Nasal obstruction/congestion
• Associated Symptoms:
  • Ocular: Itching, redness, tearing (allergic conjunctivitis)
  • Palatal itching, cough, fatigue
• Signs:
  • Allergic shiners (infraorbital edema & darkening)
  • Dennie-Morgan lines (infraorbital folds)
  • Nasal salute & transverse nasal crease
  • Pale, boggy, bluish nasal turbinates

ARIA Classification:

• Duration:
  • Intermittent: Symptoms < 4 days/week OR < 4 consecutive weeks
  • Persistent: Symptoms > 4 days/week AND > 4 consecutive weeks
• Severity (QoL impact):
  • Mild: Normal sleep & activities/work/school; no troublesome symptoms.
  • Moderate-Severe: ≥1: Sleep disturbed; activities/work/school impaired; troublesome symptoms.

⭐ Eosinophils are the predominant inflammatory cells in nasal secretions in allergic rhinitis.

Allergic Rhinitis - Calming the Storm

IgE-mediated nasal mucosal inflammation by aeroallergens (pollens, dust mites, dander). Classified: Intermittent/Persistent; Mild/Moderate-Severe.

• Core Symptoms: Paroxysmal sneezing, watery anterior rhinorrhea, nasal pruritus, and nasal congestion.
  • Associated signs: Allergic shiners, transverse nasal crease (allergic salute), Dennie-Morgan lines.
• Diagnosis:
  • Primarily clinical, based on characteristic symptoms and allergen exposure history.
  • Skin Prick Test (SPT): Preferred for identifying specific IgE sensitization. Rapid, sensitive.
  • Serum specific IgE: Useful alternative if SPT is contraindicated (e.g., dermatographism).
• Management Approach:

• Key Pharmacotherapy:
  • INCS (Intranasal Corticosteroids): Fluticasone, Mometasone. Most potent; reduce inflammation and all nasal symptoms.
  • Antihistamines (Oral 2nd Gen): Cetirizine, Levocetirizine. Rapid relief of itching, sneezing, rhinorrhea. Less sedating.
  • LTRAs (Leukotriene Receptor Antagonists): Montelukast. Beneficial for nasal congestion, especially with co-existing asthma.
• Allergen Immunotherapy (AIT): SCIT/SLIT. Disease-modifying; for selected patients with persistent mod-severe AR unresponsive to drugs, with confirmed sensitization.

⭐ Intranasal corticosteroids (INCS) are the cornerstone and most effective first-line treatment for persistent moderate-to-severe allergic rhinitis, improving all nasal symptoms.

High‑Yield Points - ⚡ Biggest Takeaways

• IgE-mediated Type I hypersensitivity reaction to common aeroallergens.
• Characterized by watery rhinorrhea, paroxysmal sneezing, nasal itching, and congestion.
• Look for allergic shiners, transverse nasal crease, and Dennie-Morgan lines.
• Key triggers include pollens, house dust mites, animal dander, and molds.
• Diagnosis: primarily clinical, supported by skin prick test or serum specific IgE.
• First-line: intranasal corticosteroids; antihistamines for symptomatic relief.
• Potential complications: ↑ risk of otitis media, sinusitis, and asthma exacerbation.