Allergic Rhinitis क्या है? – Pathophysiology

Definition

Allergic rhinitis एक IgE-mediated inflammatory disorder है जिसमें nasal mucosa allergens के प्रति hypersensitive reaction develop करता है।

Normal Immune Response vs Allergic Response

Normal:

• Body foreign substances (bacteria, viruses) से लड़ती है
• Harmless substances (pollen, dust) को ignore करती है

In Allergy:

• Immune system harmless substances को “threat” समझता है
• IgE antibodies produce होती हैं
• Exaggerated inflammatory response

Mechanism – The Allergic Cascade

Phase 1: Sensitization (First Exposure)

1. Allergen (e.g., dust mite protein) enters nose
2. Antigen-presenting cells capture it
3. Present to T-helper cells (Th2)
4. B cells activated → produce IgE antibodies specific to that allergen
5. IgE antibodies bind to mast cells in nasal mucosa
6. Person now “sensitized” (no symptoms yet)

Phase 2: Early Reaction (Subsequent Exposures)

1. Same allergen enters nose again
2. Binds to IgE on mast cells
3. Mast cell degranulation – releases mediators:
   • Histamine: Main culprit
     • Causes itching, sneezing
     • Vasodilation → nasal congestion
     • Increased vascular permeability → runny nose
   • Leukotrienes: Bronchoconstriction, mucus production
   • Prostaglandins: Inflammation
4. Symptoms appear within minutes

Phase 3: Late Phase Reaction (4-8 hours later)

• Inflammatory cells (eosinophils, basophils) recruited
• Chronic inflammation develops
• Nasal hyperreactivity – nose becomes more sensitive
• “Priming effect” – subsequent exposures cause worse symptoms

Types of Allergic Rhinitis

1. Seasonal Allergic Rhinitis (SAR) – “Hay Fever”

Triggers: Outdoor allergens, specific seasons

Common Allergens:

• Tree Pollen: Spring (March-May)
  • Common in India: Neem, Ashoka, Mulberry, Mango
• Grass Pollen: Late spring/Summer (May-July)
  • Bermuda grass, Timothy grass
• Weed Pollen: Late summer/Fall (August-October)
  • Ragweed, Parthenium (Congress grass – very common in UP)

Characteristics:

• Symptoms only during specific months
• Same time every year
• Outdoor exposure worsens symptoms
• Often associated with eye symptoms (allergic conjunctivitis)

2. Perennial Allergic Rhinitis (PAR)

Triggers: Indoor allergens, year-round

Common Allergens:

• House Dust Mites: Most common cause in India
  • Microscopic creatures living in bedding, carpets, upholstery
  • Feed on human skin scales
  • Thrive in warm, humid conditions (60-80% humidity)
  • Their feces contain allergens
• Pet Dander:
  • Proteins in skin flakes, saliva, urine
  • Cats more allergenic than dogs
  • Allergen can stay airborne for hours
• Mold/Fungi:
  • Damp areas: Bathrooms, basements
  • Outdoor: Fallen leaves, compost
  • Common in monsoon season
• Cockroach Allergen:
  • Common in urban households
  • From droppings, saliva, body parts

Characteristics:

• Symptoms throughout the year
• May have fluctuations but never completely symptom-free
• Worse indoors
• Morning symptoms common (dust mite exposure during night)

Clinical Features – Symptoms

Classic “Cardinal” Symptoms:

1. Sneezing (छींक आना)

• Paroxysmal – sudden bouts of 10-20 sneezes
• Often in morning (perennial) या on outdoor exposure (seasonal)
• Triggered by allergen exposure

2. Nasal Congestion (नाक बंद)

• Can be alternating sides
• Worse at night, affects sleep
• Leads to mouth breathing
• Causes snoring

3. Rhinorrhea (नाक बहना)

• Clear, watery discharge
• Profuse during acute episodes
• Constant dripping
• Post-nasal drip → throat irritation, cough

4. Nasal Itching (नाक में खुजली)

• Very characteristic of allergy
• Nose rubbing, “allergic salute” (upward nose rubbing – children)
• Palate, throat, ears may also itch

Associated Symptoms:

Ocular (Eye) Symptoms:

• Itching, redness (allergic conjunctivitis)
• Tearing
• Burning sensation
• Common in seasonal AR

Other:

• Fatigue: Due to poor sleep, chronic inflammation
• Headache: Sinus pressure
• Decreased smell: Nasal congestion
• Ear fullness: Eustachian tube dysfunction
• Cough: Post-nasal drip

Physical Signs (On Examination):

Nasal Examination:

• Pale, Bluish Nasal Mucosa: Characteristic (vs red in infection)
• Turbinate Hypertrophy: Swollen inferior turbinates
• Clear Secretions: Watery discharge

Facial Signs:

• “Allergic Shiners”: Dark circles under eyes
• “Allergic Crease”: Horizontal line across nose bridge (from rubbing)
• Mouth Breathing: Open mouth posture

Diagnosis at Prime ENT Center

1. Clinical History – Very Important

Key Questions:

• Symptoms: All 4 cardinal symptoms present?
• Timing:
  • Seasonal pattern? Which months?
  • Perennial with fluctuations?
  • Diurnal variation? (Worse morning/night?)
• Triggers:
  • Outdoor exposure? Gardening, parks?
  • Indoor: Dust cleaning, pets, damp areas?
  • Weather changes?
• Environmental History:
  • Home: Carpets, curtains, pets, dampness?
  • Occupation: Farming, flour mills, chemical exposure?
• Family History: Allergies, asthma, eczema in family? (Genetic predisposition)
• Response to Treatment: Antihistamines help?

2. Nasal Examination

• Anterior rhinoscopy या endoscopy
• Assess mucosal color, turbinate size
• Rule out other causes: Polyps, deviation, tumors

3. Allergy Testing

A. Skin Prick Test (SPT) – Available at Prime ENT Center

Principle: Small amount of allergen introduced into skin → if allergic, wheal forms

Procedure:

1. Usually done on forearm या back
2. Allergen extracts placed as drops
3. Skin pricked gently through drop (1mm depth)
4. Multiple allergens tested simultaneously (15-20 common allergens)
5. Wait 15-20 minutes
6. Measure wheal and flare

Interpretation:

• Positive Control: Histamine (should always react)
• Negative Control: Saline (should not react)
• Test Result: Wheal ≥3mm = Positive

Common Panel Includes:

• House dust mite (D. pteronyssinus, D. farinae)
• Grass pollen mix
• Tree pollen (local trees)
• Weed pollen (Parthenium)
• Mold (Aspergillus, Alternaria)
• Dog/Cat dander
• Cockroach

Advantages:

• Quick results (20 minutes)
• Cost-effective
• Multiple allergens tested together
• Highly sensitive

Limitations/Contraindications:

• Stop antihistamines 3-7 days before (interferes with test)
• Not in severe eczema (skin issue)
• Not in dermographism (skin too reactive)
• Recent anaphylaxis – caution

B. Serum Specific IgE (Blood Test)

When Used:

• Can’t stop antihistamines
• Severe skin disease
• Very young children (uncooperative for SPT)
• Risk of anaphylaxis

Procedure: Blood sample → lab measures IgE levels to specific allergens

Advantages:

• Medications don’t interfere
• Safer (no risk of reaction)
• Quantitative results

Limitations:

• More expensive
• Takes few days for results
• Slightly less sensitive than SPT

4. Nasal Smear for Eosinophils

• Nasal secretion examined under microscope
• Presence of eosinophils suggests allergy
• Quick, cheap screening test

Treatment at Prime ENT Center – Step-wise Approach

Step 1: Allergen Avoidance (Most Important!)

यह सबसे effective और side-effect free treatment है।

For House Dust Mite:

• Bedding:
  • Use dust mite-proof covers (allergen-impermeable) for mattress, pillows
  • Wash bedding weekly in hot water (>60°C)
  • Avoid feather pillows/quilts – use synthetic
• Flooring:
  • Remove carpets, especially bedroom
  • Hard flooring (tiles, wood) better
  • If carpets must stay, vacuum frequently with HEPA filter
• Soft Furnishings:
  • Minimize curtains, cushions
  • Use blinds instead of fabric curtains
  • Leather/vinyl furniture better than upholstered
• Humidity Control:
  • Keep <50% (dehumidifier if needed)
  • Good ventilation
• Cleaning:
  • Damp dusting (dry dusting spreads allergen)
  • HEPA vacuum cleaners
  • Patient should not do cleaning (wear mask if must)

For Pollen:

• Check daily pollen counts
• Stay indoors on high-count days
• Keep windows closed (AC if needed)
• Avoid outdoor activities early morning (peak pollen time)
• Shower and change clothes after outdoor exposure
• Wear sunglasses, mask outdoors
• Don’t dry clothes outside during pollen season

For Pets:

• Ideally, remove pet from home (difficult emotionally)
• If keeping pet:
  • Keep out of bedroom (at least)
  • HEPA air purifiers
  • Bathe pet weekly
  • Remove carpets
  • Wash hands after touching

For Mold:

• Fix leaks, dampness
• Adequate ventilation (exhaust fans in bathroom, kitchen)
• Clean moldy surfaces with bleach
• Dehumidifier in damp areas

Step 2: Pharmacotherapy (Medical Management)

1. Antihistamines

Mechanism: Block histamine receptors → reduce symptoms

Types:

• First Generation (Sedating):
  • Cross blood-brain barrier → drowsiness
  • Short-acting → 4-6 hourly dosing
  • Good for: Night-time (helps sleep), acute symptoms
• Second Generation (Non-sedating) – Preferred:
  • Don’t cross BBB significantly → minimal drowsiness
  • Long-acting → once daily
  • Better for: Daily use, school/work (no impairment)

Effective For: Sneezing, itching, rhinorrhea

Less Effective For: Nasal congestion

2. Intranasal Corticosteroids – Most Effective

Mechanism: Reduce inflammation directly in nasal mucosa

Advantages:

• Most effective single agent for allergic rhinitis
• Treats all symptoms including congestion
• Regular use → maximum benefit (not PRN)
• Minimal systemic absorption → very safe

Usage:

• Once or twice daily (as prescribed)
• Proper technique important:
  • Head slightly forward (not tilted back)
  • Spray towards lateral wall (not septum)
  • Opposite hand use (right hand for left nostril)
• Effects: Start in 12-24 hours, maximum in 1-2 weeks
• Continue throughout allergy season

Side Effects:

• Usually minimal
• Nasal dryness, crusting (rare)
• Epistaxis (rare, usually from wrong technique)
• No systemic effects at therapeutic doses

3. Oral Decongestants

• For: Nasal congestion
• Duration: Short-term only (< 5 days)
• Caution: Avoid in hypertension, heart disease, glaucoma

4. Nasal Decongestant Sprays

• Effective: Rapid relief of congestion
• Major Limitation: Rebound congestion if used >3-5 days
• Use: Only for severe acute episodes, short-term

5. Leukotriene Receptor Antagonists

• Oral medication
• Good for patients with both allergic rhinitis और asthma
• Add-on therapy

6. Nasal Antihistamines

• Spray form
• Rapid onset (15 minutes)
• Good for on-demand use

Step 3: Immunotherapy (Allergy Shots/Vaccines) – Definitive Treatment

Prime ENT Center में available – यह केवल symptomatic treatment नहीं, बल्कि disease-modifying therapy है।

What is Immunotherapy?

Gradually increasing doses of allergen दिए जाते हैं → immune system desensitized हो जाता है → symptoms reduce या eliminate हो जाते हैं।

Who Should Consider?

• Moderate to severe symptoms
• Symptoms despite medication और avoidance
• Want to reduce long-term medication
• Side effects from medications
• Identified specific allergen on testing
• Motivated for long-term commitment

Types:

1. Subcutaneous Immunotherapy (SCIT) – Allergy Shots:

• Injections under skin
• Build-up Phase: Weekly injections, dose gradually increased (3-6 months)
• Maintenance Phase: Monthly injections (3-5 years)
• Done at clinic with observation (30 min post-injection)

2. Sublingual Immunotherapy (SLIT) – Under-tongue Drops/Tablets:

• Allergen placed under tongue, held 1-2 min, swallowed
• Daily dosing
• Can be done at home (first dose supervised)
• Safer (less risk of anaphylaxis)
• Available for dust mite, some pollens

Effectiveness:

• Significantly reduces symptoms
• Reduces medication requirement
• Benefits persist even after stopping therapy
• Prevents new allergies development
• Reduces risk of asthma in allergic rhinitis patients

Contraindications:

• Severe uncontrolled asthma
• Certain cardiac conditions
• Pregnancy (don’t start, but can continue if already on)
• Beta-blocker use

Complications of Untreated Allergic Rhinitis

1. Sinusitis

• Blocked sinus drainage → infection
• Recurrent episodes common

2. Otitis Media

• Eustachian tube dysfunction
• Middle ear effusion/infection
• Common in children

3. Asthma Development

• “Allergic March” – AR often precedes asthma
• 30-40% AR patients develop asthma
• Good AR control reduces asthma risk

4. Sleep Disturbance

• Nasal congestion → poor sleep
• Daytime fatigue, impaired performance
• Children: Behavioral issues, poor school performance

5. Quality of Life Impact

• Reduced productivity
• Social embarrassment
• Emotional stress