ALLERGIC

RHINITIS

ALLERGIC RHINITIS

• IgE – mediated immunologic response to nasal mucosa to air-borne allergens.

Allergic rhinitis

seasonal

perennial

Symptoms appear in or around a particular season.

Pollen grains

Symptoms are present throughout the year

dust mites,insectparts,cockroaches,animaldanders

AETIOLOGY :

• Inhalant allergens –

• Seasonal

• perennial

• Genetic predisposition

pathogenesisIn a genetically predisposed individual

Inhaled allergen

IgE production

IgE binds to basophils & mast cells by its Fc end

On subsequent exposure allergen binds to Fab fragment

Degranulation

Chemical mediators (preformed & newly synthesized)

Sensitized

Mast cellAntigen

Release of mediators

Performed

• Histamine

• ECF – A

• NCF – A

• Heparin

•Others

Newly synthesized

• Prostaglandins e.g. PGD2

• Leukotrienes e.g. SRS-A

• PAG

• Thromboxane A

• TNFa

CHEMICAL MEDIATORS

SYMPTOMATOLOGY

• VASODILATION• MUCOSAL EDEMA• INFILTRATION WITH E.PHILS• EXCESSIVE SECRETION• SMOOTH MUSCLE CONTRACTION

2 PHASES OF ALLERGIC IMMUNE RESPONSE

Acute or early phase

• Within 5-30 min,

• Due to release of vasoactive amines like histamine

• sneezing, rhinorrhea nasal blockage and/or bronchospasm.

Late or delayed phase

• : 2-8 hours after exposure to allergen without additional exposure.

• Due to infiltration of inflammatory cells at the site of antigen deposition ( E phils, N phils, B phil, monocytes and CD4+ T cells)

• swelling.,congestion, thick secretion

Clinical features

• No age or sex predilection• Symptoms of seasonal nasal allergy.

• Paroxysmal sneezing (10-20 sneezes at a time), • nasal obstruction, • watery nasal discharge and• itching in the nose.

• Symptoms of perennial allergy.• Frequent colds, • persistently stuffy nose, • loss of sense of smell due to mucosal oedema, • postnasal drip, • chronic cough.

• Itching in the nose, eyes, pharynx or larynx.

Signs

Nasal signs : • Transverse nasal crease

• Black line in dorsum of nose due to constant upward rubbing of nose (Allergic salute )

• Pale and oedematous nasal mucosa

• Swollen turbinates

• Thin, watery or mucoid discharge

• Ocular signs• edema of lids

• Congestion

• Cobble stone appearance of conjunctiva

• Dark circles under eyes (allergic shiners)

• Otologic signsE tube blockage

↓

Retracted T M

&

Serous otitis medis

• Pharyngeal signsHyperplasia of submucosal lymphoid tissue

↓

Granular pharyngitis

• Mouth breathing• Ortho dontic changes

• Laryngeal signs• Hoarseness of voice

• Edema of vocal cords

Diagnosis : • Detailed history and physical examination.

Investigations :

1. Total and differential count. • Peripheral eosinophilia.

2. Nasal smear • large number of eosinophils.

• Also seen in NARES

3. Skin tests. • Prick, scratch and intradermal tests.

4. Radioallergosorbent test (RAST).• Measures specific IgE antibody concentration in the

patient’s serum.

5. Nasal provocation test.

Complications :

1. Obstruction of sinus ostiaRecurrent sinusitis.

2. Nasal polyp

3. Blocking of E tube Serous otitis media

4. Bronchial asthma.

5. Mouth breathing orthodontic changes

Treatment : 1. Avoidance of allergen.2. Treatment with drugs.

a. Antihistaminics• Decrease rhinorrhea ,sneezing ,nasal itch• A/E :drowsiness

b. Sympathomimeticsa. topically / orallyb. Oral pseudoephedrine & phenylephrine in combn with antihistaminesc. Cause vasoconstriction ↓ nasal congestion & edemad. CNS activation ↓dowsiness due to antihistaminese. Topical aerosols } phenylephrine , xylometazoline & oxymetazoline

a. ↓ nasal obstructionb. A/E rebound congestion RHINITIS MEDICAMENTOSA

c. Corticosteorids• Oral corticosteorids• acute episodes not relieved by other drugs• Topical steroids } aerosols }beclomethasone budesonide, flunisolide , fluticasone• Inhibit recruitment of inflammatory cells trt of late allergic phase

• Trt of RHINITIS MEDICAMENTOSA

a) Sodium chromoglycate• Stabilizes the mast cells & prevents degraulation.• 2% solution for nasal drops or spray or as an aerosol powder

• anticholinergics↓rhinorrhea• Ipratropium bromide• Trt of allergic & nonallergic

• leukotriene receptor antagonist• monteleukast

• anti ig E ↓igE• omalizumab

3. Immunotherapy • Allergen is given in gradually increasing doses till the

maintenance dose is reached.• ↓ formation of IgE & ↑ IgG• Upto 3 years