Allergy Flashcards
What are the risk factors for allergy?
Hereditary Race Age Environmental factors- exposure to infectious diseases, enviromental pollution, allergen levels and dietary changes Occupational
How does allergy present in the different body systems?
Skin- urticaria/angioedema
Upper respiratory- rhinitis
Lower respiratory- asthma
Systemic- anaphylaxis
What are the risk factors of allergic rhinitis?
Atopy
Family history
Environmental factors
What are the symptoms of allergic rhinitis?
Sneezing Itch Nasal blockage Rhinorrhoea Chronic obstruction Hyposmia Hyperreactivity History of asthma or eczema
How does a type 1/immediate hypersensitivity reaction occur?
Sensitisation- plasma cells produce IgE, binds to mast cells
Re-exposure- Mast cells degranulate, release histamine, leukotrienes, prostaglandins and chomotactic factors
Describe the acute response to an allergen
Exposure of allergen triggers release of allergen specific IgE, which causes degranulation with release of histamine etc from granules causing systemic effects such as vasodilation, mucous secretion, nerve stimulation and smooth muscle contraction
When does a late-phase response occur and why?
2-4 hours after exposure to allergen
Due to migration of other leukocytes (neutrophils, lymphocytes, eosinophils and macrophages to initial site)
What is allergic rhinitis and when does it occur?
Allergic inflammation of the nasal airways
Occurs when allergen is inhaled by an individual with a sensitised immune system
How is allergy diagnosed?
Skin test RAST- presence and levels of allergen-specific IgE Total serum IgE Nasal allergen challenge Nasal cytology
How is allergy treated?
Allergen avoidance- education Pharmacotherapy: -Topical intranasal steroids -Systemic steroids -Antihistamines -Sodium cromoglycate -Allergen immunotherapy -Anti-IgE
