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Flashcards in Allergy Testing Deck (37)
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1

What are the four different types of allergy tests?

immediate hypersensitivity skin testing, serum IgE antibody testing, nasal smears for eosinohils, delayed hypersensitivity skin tests (patch testing)

2

What are the two most common food allergens for anaphylactic rxns?

peanut and seafood

3

During what season are tree and grass pollens common?

spring

4

During what season are weed pollens common?

late summer/fall

5

What does a personal or family history of atopic disease put someone at risk for?

allergies

6

What diseases are included in the atopic triad?

allergic rhinitis, eczema, asthma

7

What is atopy?

tendency to be “hyperallergic”

8

What are indications for allergy testing in someone who has rhinitis?

Symptoms not controlled by medications and allergen avoidance

9

What are indications for allergy testing in someone who has asthma?

Persistent asthma in patients exposed to perennial indoor allergens

10

What are indications for allergy testing in someone who has a suspected food allergy?

Previous suspected systemic reaction to food

11

What are indications for allergy testing in someone who has a suspected drug allergy?

Previous suspected systemic reaction to drug, and clinical indication for suspected drug

12

What are indications for allergy testing in someone who has a suspected insect sting?

Previous suspected systemic reaction to insect sting

13

What disease conditions is an immediate hypersensitivity test used to diagnose?

allergic rhinitis, allergic asthma, food allergy, penicillin allergy and stinging insect hypersensitivity

14

Who is at high risk for anaphylaxis during an immediate hypersensitivity skin test?

Poorly controlled asthma and reduced lung function. History of severe reactions to small amounts of allergen. Significant cardiovascular disease and elderly patients

15

What kind of allergy testing should be done if patients can't have a hypersensitvity skin test?

immunoassay allergy testing

16

Why are beta blockers and ACE inhibitors contraindicated for skin tests?

they mask symptoms of anaphylaxis

17

Why might a skin test yield false negative results?

mast cell refractory period

18

Why should patients who have skin conditions (dermographism, urticaria, and cutaneous mastocytosis) not be skin tested?

false positive results are common

19

What is dermatographism?

caused by mast cells in the surface of the skin releasing histamines without the presence of antigens, due to the presence of a weak membrane surrounding the mast cells.

20

What is mastocytosis?

group of rare disorders of both children and adults caused by the presence of too many mast cells

21

Why are skin tests typically not done for patients who are currently taking TCAs, muscle relaxants, or antimemtic druge?

these drugs would need to be stopped for up to 2 weeks. do serum testing instead

22

How would tacrolimus (Protopic) used to treat eczema, affect a skin test?

decrease skin reactivity, give false negative

23

What are benefits of skin testing?

Most rapid, sensitive, and cost effective testing modality for the detection of IgE-mediated disease

24

How is a positive skin test determined?

Wheal equal or larger in size to that associated with histamine control. Wheal diameter larger than 3mm (histamine control usually produces wheal about 3mm diameter

25

How do intradermal injections compare to percutaneous injections?

higher sensitivity but lower specificity

26

For what suspected allergens do you reserve intradermal injections?

venom and PCN when percutaneous tests are negative

27

What is there a greater risk of with intradermal injections?

systemic rxn

28

What are the general principles for the interpretation of a positive skin test?

result ONLY indicates presence of IgE specific to that allergen. You can be sensitized to something but that doesn’t mean it is an allergy

29

What is the only medication that skin testing has been standardized for?

PCN (penicillin)

30

How does the specific IgE (RAST) test compare to skin testing?

less sensitive, more expensive