Flashcards in Allergy - HS type I Deck (13):
What type of hypersensitivity is allergy?
What immunoglobulin is involved in allergic reactions and explain how they cause a reaction?
Antigen specific IgE antibodies
Mast cell expresses receptors for IgE, allergen cross links IgE bound to mast cells, causing mast cell degranulation
How does an allergic reaction differ from a normal adaptive immune response?
Normal - TH1 cells produce IgG antibodies
Allergy - TH2 cells produce IgE antibodies
Where are mast cells found?
Produced in bone marrow
Skin (dermis and epidermis)
Name the mast cell mediators and their function
Histamine - increased vascular permeability and bronchoconstriction
Leuokotrines - smooth muscle contraction and increased vascular permeability
Tryptase - remodels connective tissue
Platelet activating factor - attracts leukocytes
Systemic activation of mast cells, a type I hypersensitivity reaction
Describe the systemic features of anaphylaxis
Upper airway obstruction with stridor
Lower airway obstruction with wheeze
Describe the steps of treating anaphylaxis
-Using an epi pen to administer adrenaline intramuscularly -
Remove safety cap
Place epi pen against mid antero-lateral thigh
Inject with audible click
Hold device in for 10 s
Massage injection site for 10s
Describe management of allergies
Strict avoidance of potential triggers
Epi pen training and carrying at all times
Medical alert bracelet
Referral to allergy clinic for skin prick tests
Oral reintroduction in gradual increasing amounts to desensitise
Give a dermatological description of urticaria
Errythematous, well defined papules
Describe the type of reaction that produces urticaria
Type I hypersensitivity reaction within the epidermis, caused by mast cell reaction
What drugs are used to treat allergic reactions?
Corticosteriods eg prednisolone
Leukotrine receptor antagonist
Anti - IgE monoclonal antibody