Allergic rhinitis ent

Definition: An IgE-mediated immunologic response of nasal mucosa to airborne allergens, characterized by watery discharge, obstruction, sneezing, and itching.

Classification & Etiology

Type	Triggers (Allergens)
1. Seasonal	Pollens (Trees, Grasses, Weeds). Varies geographically.
2. Perennial	Present throughout the year. Molds, Dust Mites, Cockroaches, Animal Dander.

*Genetic Predisposition: 20–47% risk if parents are allergic.

Pathogenesis Flowchart

Phases of Reaction

• Early Phase (5–30 min): Sneezing, rhinorrhoea, blockage. Due to Histamine.
• Late Phase (2–8 hours): Cellular infiltration (Eosinophils, neutrophils). Swelling & congestion.
• Priming Effect: Mucosa becomes hyper-reactive; reacts to smaller doses or non-specific stimuli.

Clinical Features

Symptoms (Tetrad)

• Paroxysmal Sneezing (10–20 at a time).
• Watery Nasal Discharge.
• Nasal Obstruction.
• Itching (Nose, Eyes, Palate, Pharynx).

Specific Signs

• Nose:
  • Allergic Salute: Transverse nasal crease (from upward rubbing).
  • Pale, bluish, oedematous mucosa.
• Eyes:
  • Allergic Shiners: Dark circles under eyes.
  • Cobble-stone conjunctiva.
• Pharynx: Granular pharyngitis.

Diagnosis (ARIA Guidelines)

ARIA: Allergic Rhinitis and Its Impact on Asthma.

Duration	Severity
Intermittent: < 4 days/week OR < 4 weeks.	Mild: Normal sleep, daily activities, work/school.
Persistent: > 4 days/week AND > 4 weeks.	Mod-Severe: Disturbance of sleep, activities, or troublesome symptoms.

Investigations

• Skin Prick Test: Excellent method. Shows Wheal & Flare reaction within 15 mins.
• Specific IgE (RAST): In vitro test (serum).
• Nasal Smear: Shows large number of Eosinophils.

Treatment

1. Avoidance

• Eliminate allergens (encase mattresses, remove pets/carpets).

2. Pharmacotherapy

• Antihistamines: Control sneezing/itching. (Side effect: Drowsiness).
• Nasal Steroids: Most Effective for inflammation (esp. in moderate/severe cases).
• Decongestants: Alpha-adrenergics (relieve congestion).
• Mast Cell Stabilizers: Sodium Cromoglycate (prevent degranulation).
• Leukotriene Antagonists: Montelukast (well tolerated).

3. Immunotherapy

• Indication: Drug failure or severe side effects.
• Mechanism: Suppresses IgE / Raises IgG.
• Routes: Subcutaneous (SCIT) or Sublingual (SLIT).