Intradermal testing

Question 1

Tests of cell-mediated immunity

Answer 1

Allergenic extracts are injected intradermally & the sites are monitored for allergic reactions

Question 2

Allergens

Answer 2

Substance that causes an allergic reaction

Question 3

Urticaria

Answer 3

Hives

Question 4

Wheals

Answer 4

Swelling on the surface of the skin

Red welts

Question 5

Angioedema

Answer 5

Edema of the dermis & subcutaneous tissues

Question 6

What antibody, leukocyte, and cells are active during allergic reactions

Answer 6

IgE, basophils, and mast cells

Question 7

What is intradermal testing?

Answer 7

Tests of cell-mediated immunity

Question 8

What species do we do intradermal testing?

Answer 8

Dogs

Question 9

Can dogs have allergies to more than one allergen?

Answer 9

Yes

Question 10

What are the allergens based on?

Answer 10

Geography and patient history

Question 11

What testing has not been vaildated yet?

Answer 11

Intradermal testing for food allergies

Question 12

What are reactions triggered by?

Answer 12

Basophils and/or mast cells releasing histamine-containing granule that invoke an inflammatory response

Question 13

How do you prepare a dog for intradermal testing?

Answer 13

Shave the hair on the lateral thorax

Question 14

What do you use to mark injection sites?

Answer 14

Felt-tip marker

Question 15

How far apart should the injection sites be?

Answer 15

2cm

Question 16

What gauge needle do you use to inject the specifically selected antigen?

Answer 16

26 gauge needle

0.05mLs of specifically selected antigen

Question 17

When do you evaluate the injection sites?

Answer 17

15 and 30 minutes

Question 18

How do you grade the sites?

Answer 18

Based on the controls

Measure the diameter of the wheal

Question 19

What is the positive control?

Answer 19

Histamine

Question 20

What is the negative contorl?

Answer 20

Saline

Question 21

What are reasons for false negative reactions?

Answer 21

Subcutaneous injection
Too little antigen
Drug interference 
Anergy
Inherent host factors
Endoparasitism or ectoparasitism
Off-season testing
Histamine

Question 22

False negative reactions: Drug interference

Answer 22

Glucocorticoids
Antihistamines
Tranquilizers
Progetational compoinds
Drugs that lower blood pressure

Question 23

False negative reactions: Anergy

Answer 23

Testing during peak hypersensitivity reaction

Question 24

False negative reactions: Off-season testing

Answer 24

Testing more than 1-2 months after clinical signs have disappeared

Question 25

False negative reactions: Histamine

Answer 25

Hyporeactivity

Question 26

What are the reasons for false positive reaction?

Answer 26

``` Irritant Test allergens Contaminated test allergens Skin-sensitizing antibody only Poor technique Substance that cause nonimmunologic histamine release Irritable skin Dermatographism Mitogenic allergen ```

Question 27

False positive reactions: Irritant test allergens

Answer 27

Contain glycerin, house dust, feathers, wool, old and all food preparations

Question 28

False positive reactions: Contaminated test allergens

Answer 28

Bacteria or fungi

Question 29

False positive reactions: Poor technique

Answer 29

Traumatic placement of the needle Dull or burred needle Too large volume injected Air injected

Question 30

False positive reactions: Substances that cause nonimmunologic histamine release

Answer 30

Narcotics

Question 31

False positive reactions: Irritable skin

Answer 31

Large reactions seen to all infected substances

Question 32

What does a positive reaction look like?

Answer 32

A raised welt that indicates the animal is allergic to the antigen

Question 33

What do hypersensitive reactions look like?

Answer 33

Urticaria (hives), wheals, or angioedema

Question 34

Why do hypersensitivity reactions occur

Answer 34

The dog has allergies to more than one allergen

Question 35

What are common allergies?

Answer 35

Grass, trees, pollen, molds, dust

Question 36

What is the goal of intradermal testing?

Answer 36

To create allergy shots to desensitize the animal to the allergens

Question 37

What is the ELISA test developed for allergies?

Answer 37

ALLERCEPT

Question 38

What does ALLERCEPT determine?

Answer 38

The specific IgE antibodies in dogs, cats and horses

Question 39

What does ALLERCEPT test for?

Answer 39

Grasses, trees, weeds, mites, insects, and fungi

Question 40

How do you do the tuberculin test?

Answer 40

Inject tuberculin intradermally at a site in cervical region or skin fold at the base of the tail

Question 41

What animals is the tuberculin test commonly performed on?

Answer 41

Cattle and primates

Question 42

What do animals with Mycobacterium spp develop?

Answer 42

A delayed hypersensitivity reaction to the organism tuberculin

Question 43

Why is it a delayed reaction?

Answer 43

Because T lymphocytes must migrate to the foreign antigen injected

Question 44

What does the tuberculin test actually test for?

Answer 44

Mycobacterium