2.immediate hypersensitivity reaction because signs/symptoms of allergic reaction occurs immediately after contact with an allergen.
- 3.Mast cells are the principal effector cells, with cross-linking of IgE receptors on mast cell membranes the stimulus for degranulation and release of chemical mediators, including histamine which causes reactions like:
- a.Increased vascular permeability
- b.Vasodilatation (with flushing)
- d.Smooth muscle constriction
- f.Increased gut permeability
4.Treatment ranges from: nothing (mild cases), antihistamines, epinephrine, steroids, allergic desensitization, allergen avoidance, mast cell stabilization, etc.