Flashcards in ENT Allergy Deck (13):
What is the definition of allergy?
Hypersensitive disorder of the immune system
How do hypersensitive allergic reactions occur?
Reaction occur to normally harmless substances known as allergens; these reactions are acquired
Give an example of an allergic:
Skin - Urticaria/angioedema
Upper respiratory: Rhinitis
Lower respiratory - asthma
Systematic - anaphylaxis
What is the pathophysiology of type 1 (hypersensitivity reactions)
Sensitisation - Plasma cells produce IgE (binds to mast cells)
Rexposure - mast cells degranulate releasing histamine, leukotrienes, prostaglandins and chromotactic factors
What is the physiological effect of mast cell degranulation?
Causes vasodilation, increased vascular permeability, leukocyte infiltration (especially eosinophils)
What is allergic rhinitis?
Allergic inflammation of the nasal airways
What are the risk factors for allergic rhinitis?
Atopy, FHx, environmental factors
What are the immediate and latent effects of allergic rhinitis?
Immediate - sneezing, itching, nasal blockage, rhinorrhoea
Latent - chronic obstruction, hyposmia, hyperactivity
What are the two classifications of duration of allergic rhinitis?
Intermittent (symptoms lasting <4 days/week or < 4 consecutive weeks)
Persistent (>4 days/week and >4 consecutive weeks)
What are the two classifications of severity of allergic rhinitis?
Mild - symptoms present but not troublesome
Moderate-severe - sleep disturbance, impairment of activities, issues at school/work, troublesome symptoms
What principle investigations are appropriate for allergic rhinitis?
Skin test - tests response to known allergens
RAST - tests presence of specific allergen IgE ni serum
What other investigations are indicated for allergic rhinitis?
- Total serum IgE
- Nasal Allergen challenge
- Nasal cytology