Allergy Flashcards
What are the risk factors for allergies?
Host factors = heredity, race, age
Environmental factors = alterations in exposure to infectious diseases during early childhood, pollution, allergen levels, dietary changes
Occupational = flour, latex, wood dust
What are the immediate symptoms of allergic rhinitis?
Sneezing
Itch
Nasal blockage
Rhinorrhoea
What are the late symptoms of allergic rhinitis?
Chronic obstruction
Hyposmia
Hyperreactivity
What is the definition of allergy?
A hypersensitive disorder of the immune system
What is an allergen?
Antigen that causes allergic reactions
How does sensitisation occur in type 1 hypersensitivity reaction?
Plasma cells produce IgE
Bind to mast cells
What happens in re-exposure in type 1 hypersensitivity reaction?
Mast cells degranulate
Release histamine, leukotrienes, prostaglandins and chomotactic factors
What is an allergic reaction?
An exaggerated or inappropriate immune reaction and causes damage to the host
What happens in an acute response?
Degranulation with release of histamine, cytokines, interleukins, leukotrienes, prostaglandins from their granules causes systemic effects such as vasodilation, mucous secretion, nerve stimulation and smooth muscle contraction
What is a late-phase response?
2-4 hours
Due to migration of other leukocytes (neutrophils, lymphocytes, eosinophils and macrophages) to the initial site
What is allergic rhinitis?
Allergic inflammation of the nasal airways
Occurs when allergen is inhaled
How are allergies diagnosed?
Skin test: responses to allergen RAST: presence and levels of allergen-specific IgE Total serum IgE Nasal allergen challenge Nasal cytology
How are allergies treated?
Avoidance - education Immunotherapy Pharmacotherapy - topical intranasal steroids - systemic steroids - antihistamines - sodium cromoglycate - allergen immunotherapy - anti-IgE
