Allergy Flashcards
What is an allergy?
Hypersensitivity disorders the immune system
What does an allergy cause?
Inappropriate or exaggerated immune reaction, causing damage to the host
What do allergic reactions normally occur against?
Allergens- harmless environmental substances, usually proteins
What causes variation in the symptoms of an allergy?
Individual
Allergen
Mode of introduction
What is an allergic reaction of the skin called?
Urticaria/angiodema
What is an allergic reaction of the upper respiratory tract called?
Rhinitis
What is an allergy of the lower respiratory tract called?
Asthma
What is a systemic allergic reaction called?
Anaphylaxis
What is the pathology of an allergy?
Hypersensitivity due to IgE antibodies
What happens in the sensitisation stage of a hypersensitivity reaction?
Plasma cells produce IgE against allergen, which then bind to mast cells
What happens in the re-exposure phase of a hypersensitivity reaction?
IgE activated and mast cells degranulate and causes allergic reaction
What does mast cell degranulation release?
Histamine
Leukotrines
Prostaglandins
Chromotactic factors
What does mast cell degranulation physiologically cause?
Vasodilation
Vascular permeability
Smooth muscle contraction
Leukocyte infiltration
What is the late phase response?
Migration of leukocytes to initial site 2-4 hours after insult
What are the risk factors for an allergy?
Hereditary, race, age
Exposure to infectious disease as child, pollution, allergen levels, dietary changes
Flour, latex, wood dust