ALLERGIC RHINITIS Dr Gary Kroukamp ALLERGIC RHINITIS Ig

ALLERGIC RHINITIS Dr Gary Kroukamp

ALLERGIC RHINITIS Ig. E-Mediated Type 1 hypersensitivity reaction

n In the mucous membranes of the nasal airways (closely linked to allergy affecting rest of URT)

Allergic Rhinitis n Affects 30% of population n Can be: seasonal perennial (with or without seasonal exacerbations)

Aetiology n Allergens: soluble proteins or glycoproteins pollens moulds house dust mite animal epithelia

Pathogenesis Allergen interacts with cell-bound Ig. E n Triggers chain of events which causes release of prostaglandin D, leukotrines & other chemotactic factors, causing n Mast cell disruption – histamine, proteases n Capillaries more permeable n Eosinophil infiltration n Oedema n

Typical features n Vascular congestion n Oedema n Rhinorrhoea n Irritation - sneezing

Clinically n Seasonal - early summer to autumn, depending on allergen n Rhinorrhoea, nasal irritation, sneezing + itchy and watering eyes n Family history of atopy n Previous history of dermatitis or astma

Clinically n Perennial - may have seasonal exacerbations n Almost invariably house dust mite n Turbinate hypertrophy - nasal obstruction hyposmia

Clinically n Nasal mucosa - moist pale swollen (turbinate hypertrophy) Sometimes mucosa red and turbinates have blue tinge

Investigations n Skin tests - flexor aspect forearm - wheal and flare in 20 min Negative control n Positive control n - carrier substance - histamine (Resus equipment in case of anaphylaxis)

Investigations n Blood tests - PRIST - RAST (plasma radio-immunosorbent test) (radioallergosorbent test) Safer but expensive and no diagnostic superiority over skin tests

Investigations n Nasal smears - increased eosinophils - indicates allergy - not diagnostic

Investigations n Provocation tests - a drop of suspected allergen in nose causes symptoms

Management n Avoidance - of the allergen(s) - obviously helpful - not always practical

Management n Oral antihistamines - selectively block histamine receptors now non-sedating now once daily dose (intranasal antihistamine sprays now available)

Management n Topical steroid sprays - MAINSTAY of treatment - safe and effective - rarely cause crusting and bleeding - systemic absorption negligible - do not promote fungal ifections

Management n Depot IM steroids and Oral steroids - work!!! - reserved for when symptoms interfere with special events - weddings - examinations - etc.

Management n Topical anticholinergics - rhinorrhoea predominant n Sodium cromoglycate - mast cell stabiliser - 5 or 6 x daily - conjunctivitis benefits n Desensitisation - 1 or 2 allergens only - pollen usually - anaphylaxis risk

Management n Surgery - not for symptom control - turbinate surgery for sever obsruction

After-care n Most allergic rhinitis managed by GP n Advice on avoidance if allergen identified n Nasal abnormalties - nasal septal deviation - turbinate hypertrophy - sinus disease

After-care n Nasal abnormalties - nasal septal deviation - turbinate hypertrophy - sinus disease - may complicate and exaggerate symptoms - treated on their own merit