Allergy Testing

Question 0

Atopic Triad

Answer 0

Allergic rhinitis and conjunctivitis, allergic asthma, eczema (atopic dermatitis)

Question 1

Atopy

Answer 1

Tendency to be “hyperallergic”

Question 2

Indications for allergy testing

Answer 2

Rhinitis not controlled by meds and avoidance, persistent asthma, previous suspected systemic reaction to food drug or sting

Question 3

2 different approaches

Answer 3

Focused - when cause is obvious

Broad - when cause is not known

Question 4

Immediate-Type hypersensitivity reaction

Answer 4

Skin prick/scratch or intradermal

Question 5

Immediate-Type hypersensitivity reaction uses

Answer 5

Most commonly used in diagnosis or allergic rhinitis, allergic asthma, food allergy, penicillin allergy, and stinging insect allergy

Question 6

High risk anaphylaxis patients

Answer 6

Poorly controlled asthma
History of severe rxn to small amt
Significant cardiovascular disease and the elderly
Recent anaphylaxis

Question 7

What to do when there is a high risk for anaphylaxis?

Answer 7

Immunoassay allergy testing should be done initially

Question 8

Skin testing contraindications - meds

Answer 8

Presence of beta 2 antagonists and ACE inhibitors may inhibit management of anaphylaxis

Tricyclic antidepressants, muscle relaxants, antiemetics must be stopped for 2 weeks (get serum)

Topical tacrolimus may affect results

Question 9

Skin testing contraindications - skin

Answer 9

Dermographism, urticaria, cutaneous mastocytosis cannot be tested, high false positive results
Rash or skin changes can make test difficult to interpret

Question 10

Intradermal injections

Answer 10

Higher risk for systemic rxn
Only performed after negative prick
Not used for food or latex
Tested allergen is 10-100x more diluted

Question 11

Specific IgE (RAST) testing

Answer 11

Blood test measures levels of IgE produced when your blood is mixed with a series of allergens in a lab

Question 12

RAST testing vs. skin testing

Answer 12

Less sensitive (25% test positive when actually negative)
More expensive
Use when high anaphylaxis risk or interacting meds are present

Question 13

Nasal Smears

Answer 13

Useful when determining if it is rhinitis vs. infxn

Usually shows eosinophils for allergic, neutrophils for infection

Question 14

Wright stain

Answer 14

Used to differentiate blood cells (as in nasal smear)

Question 15

Hansel stain

Answer 15

Combo of wright and geimsa stains, causes eosinophils to turn red, remaining cells and background are blue

Question 16

MOST IMPORTANT part of allergy assessment is…

Answer 16

Clinical history

Question 17

Positive skin test, now what?

Answer 17

Needs to be confirmed by clinic history of reactivity and in some cases allergen challenge to be sure

Question 18

Most appropriate time to consider allergy testing?

Answer 18

If pt could benefit from immunotherapy