Allergic Rhinitis Flashcards
Allergic Rhinitis Definition
Rhinitis is inflammation of the lining of the nose causing symptoms including anterior and posterior rhinorrhoea, sneezing, nasal blockage, itching of the nose and loss of the sense of smell. The commonest causes are infections (Acute rhino sinusitis) and allergy (allergic rhinitis)
Allergic Rhinitis Epidemiology
Over the last decade, the prevalence of allergic rhinitis has increased worldwide, affecting 20% of the adult population and up to 40% of children. The peak prevalence is in the second decade.
Allergic Rhinitis Aetiology
It is caused by environmental allergens and can be aggravated by chemical irritants (e.g. active or passive smoking).
Allergic and infective rhinitis are increasingly regarded as interrelated and part of a spectrum of inflammatory airway disease
The common allergens are:
- Seasonal
- Perennial
Allergic Rhinitis Seasonal Allergens
Pollens of trees, grass and mould cause seasonal bouts of AR. The loads of different pollens vary between regions
Allergic Rhinitis Perennial Allergens
- House-dust mite and faeces (80% of AR patients are +ve to a skin prick test of this allergen)
* Pollen grains (70%)
* Domestic pets (40%)
* Moulds (20%)
Note the presence of perennial rhinitis makes the nose more reactive to irritants (cigarette smoke, washing powders, household detergents, strong perfumes, and traffic fumes) and although patients often believe they are allergic to these stimuli, these are irritant responses not allergic immune reactions.
Allergic Rhinitis Pathogenesis
Allergic rhinitis (AR) is mediated by IgE lining in the nose after allergen exposure. Allergic individuals become sensitised to and may develop IgE antibodies against allergens. On further exposure to the specific allergen IgE binds to mast cells, causing degranulation and leading to release of chemical mediators that cause rhinorrhoea, sneezing and itching (early-phase response). Several hours later there is the infiltration of inflammatory cells causing congestion (late-phase response).
Allergic Rhinitis Clinical Presentation
- Rhinorrhoea
- Sneezing
- Nasal blockage
- Itching of the nose
- Loss of smell
- Seasonal attacks of asthma (20%)
Nasal polyps can form in patients with AR. These are round, smooth, soft structures that are attached to the sinus mucosa by a narrow stalk. They contain mast cells and not cause obstruction.
Allergic Rhinitis Severity Classification Symptoms
Symptoms (absent or present)
- Sleep disturbance
- Impairment of ADL, leisure of sport
- Impairment of school or work
- Troublesome symptoms
- Mild AR
- None of these symptoms are present
- Moderate to Severe AR
- 1+ of these symptoms are present
- Severe AR
- Markers in paediatrics
- Persistent mouth breathing
- Allergic facies
- Dental crowding
- Markers in paediatrics
Allergic Rhinitis Investigations
- Skin-prick test
* RAST test
Allergic Rhinitis Management
Mild Intermittent Symptoms (and/or)
- Oral or Intranasal Antihistamine
- Decongestant (not for kids or for >5 days)
Mod-Severe Intermittent or Persistent symptoms
- Oral or Intranasal Antihistamine
- Decongestant (not for kids or for >5 days)
- Leukotriene receptor antagonist
- For Persistent review after 2-4 weeks
Allergic Rhinitis Medications
DIAL MI
- Decongestants
- Phenylephedrine - can be oral or intranasal
- Inhaled Corticosteroids
- Beclomethasone nasal spray
- Antihistamines
- Cetirizine 10mg oral
- Leukotriene receptor antagonist
- Montelukast oral
- Mast Cell Stabilisers
- 2nd line approach to prevention (preferred to ICS in kids)
- Sodium cromoglycate (cromolyn) nasal
- Intranasal anticholinergic (antimuscarinic)
- Indicated for rhinorrhoea
- Ipratropium bromide
