Allergy - HS type I Flashcards Preview

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Flashcards in Allergy - HS type I Deck (13):
1

What type of hypersensitivity is allergy?

Type I

2

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

3

How does an allergic reaction differ from a normal adaptive immune response?

Normal - TH1 cells produce IgG antibodies
Allergy - TH2 cells produce IgE antibodies

4

Where are mast cells found?

Produced in bone marrow
GI tract
Skin (dermis and epidermis)
Resp. epithelium
Connective tissue

5

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

6

Define anaphylaxis

Systemic activation of mast cells, a type I hypersensitivity reaction

7

Describe the systemic features of anaphylaxis

Generalised urticaria
Angioedema
Hypotension
Upper airway obstruction with stridor
Lower airway obstruction with wheeze
Cyanosis
Palpitations
N/V
Dizziness

8

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

9

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

10

Give a dermatological description of urticaria

Errythematous, well defined papules

11

Describe the type of reaction that produces urticaria

Type I hypersensitivity reaction within the epidermis, caused by mast cell reaction

12

What drugs are used to treat allergic reactions?

Anti histamines
Corticosteriods eg prednisolone
Leukotrine receptor antagonist
Anti - IgE monoclonal antibody

13

How long does an allergic reaction take to develop?

<30 mins