Allergic rhinitis

Definition

1. IgE mediated immunological response of nasal mucosa to air borne allergen
2. Characterized by sneezing, itching, watery nasal discharge, nasal obstruction

Aetiopathogenesis

1. IgE mediated hypersensitivity reaction to specific allergen
2. Allergens
1. pollen, grass, weeds- seasonal allergic rhinitis
2. House dust mite, animal hair, dander, perfumes, feathers, smoke, dust, atmospheric pollutant- perennial allergic rhinitis

Types

1. Seasonal allergic rhinitis (Hay Fever)
1. Inhaled allergen- pollen grain
2. Certain season –spring, autumn
2. Perennial allergic rhinitis
1. Occur throughout year
2. Caused by house dust mite etc

Clinical features

1. B/L nasal obstruction
2. Rhinorrhoea
3. Paroxysms of sneezing
4. Hyposmia
5. Post nasal drip
6. Itchiness of nose, eyes, palate
7. Associated  other allergy

Signs

1. Boggy, bluish edematous turbinates
2. Excessive nasal secretions

Sequelae

1.     Regression

2.     Progression to bronchial asthma, ethmoidal polyp

3.     Recurrent sinusitis

4.     Serous ottitis media

Investigations

1. Nasal smear microscopy- eosinophilia
2. Skin prick test- 10-30% asymptomatic- positive test
3. RAST (radioallerosorbent test)
4. Serum IgE
5. Nasal provocation test
6. Scratch test

Treatment

1. Avoidance of allergens
2. Medication
1. Antihistaminics-

                                                               i.      Cetrizine  10-20mg BD

                                                             ii.       Fexofenadine 120-180mg daily

                                                            iii.       loratadine

2. Topical corticosteroids spray-

                                                               i.      fluticasone,

                                                             ii.      momentasone,

                                                            iii.      budesonide,

                                                            iv.       beclomethasone 200mcgbd or 100mcg 3-4times

3. Mast cell stabilizers- sodium chromoglycate
4. Nasal decongestant-

                                                               i.      oxymetazoline,

                                                             ii.      xylometazoline

5. Oral steriod : for severe symptoms
2. Desensitization
1. Blocking IgG antibody that prevent antigen binding to IgE
2. Effective for seasonal allergy
3. Drawbacks

                                                               i.      Multiple allergy

                                                             ii.      Difficult to identify exact allergen

                                                            iii.      Series of injections

                                                            iv.      Anaphylaxis

                                                             v.      Recurrence