IgE Mediated
(Type I) Hypersensitivity
Type I (immediate)
hypersensitivity occurs when an immunoglobulin E
(IgE) response is directed against innocuous
environmental antigens, such as pollen,
house-dust mites or animal dander. The resulting
release of pharmacological mediators by IgE
sensitized mast cells produces an acute
inflammatory reaction with symptoms such as
asthma or rhinitis. Type I hypersensitivity is
characterized by an allergic reaction that
occurs immediately following contact with the
antigen, referred to as the allergen. The term
allergy meaning “changed receptivity of the host
when meeting an agent” on a second or subsequent
occasion.
Typical examples
of allergic reactivity
1.
Hay fever
2.
Asthma
3.
Atopic eczema
4.
Drug allergy
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