Rola Hmede Allergy

Question 1

Define allergy (hyper sensitivity/ sensitivity)

Answer 1

Certain dzs in which immune responses to harmless environmental Ags causes tissue inflammation and organ dysfunction

Question 2

An allergen is any Ag that causes allergy
T or f

Answer 2

T

Question 3

Allergen can be only a complete protein Ag

Answer 3

F
It can be a complete protein Ag ( pollen and animal dander)
Or low molecular wt proteins
That can elicit an IgE response

Question 4

Atopy

Answer 4

Inherited propensity to respond immunologically to such common naturally occurring Allergens with continuous production of IgE Ab

Question 5

How do the allergen enter the body

Answer 5

Thru
Ingestion
Inhalation
Skin contact
Injection

Question 6

Based on mechanism and time taken for the reaction we can distinguish 4 types of allergic rxn
T or f

Answer 6

T

Question 7

Type I Hypersen (immediate and anaphylactic Hypersensitivity )involves IgG and IgM
T or f

Answer 7

F
It involves IgE

Question 8

Type I hypersen always takes too much time from allergen exposure to symp appearance

Answer 8

F
-The rxn usually takes 15-30mins (secs to minutes after exposure)
-Although sometimes it may have delayed onset (10-12hrs) —> if allergen causes a rxn after it is partially digested
-VERY RARE CASES rxn develop after 24hrs

Question 9

What are the main cells involved in type I hypersen

Answer 9

Mast cells and basophils, they are mainly seen on a biopsy from rxn site

Question 10

Where are these cells mostly located

Answer 10

In the :
-skin
-mucosa of resp
-mucosa of GI tract
In these areas the atopic rxn localizes the most

Question 11

Also when mast cells are stimulated by exercise, emotional stress and chemicals this rxn is called hypersensitivity rxn

Answer 11

F
These rxns are mediated by agents without IgE allergen interaction so they are not hypersensitivity rxns although they produce same symptoms

Question 12

List the 4 major mediators produced by mast cells that cause the pathophysiology of the immediate and late phases of atopic dz

Answer 12

Histamine
Tryptase
Proteoglycans (heparin, chondroitin sulfate)
Chemotactic factors

Question 13

The mediators can activate more WBC

Answer 13

T
They have effects on local tissue and organs and activate more WBC defenders

Question 14

If the release of mediators is sudden and extensive the rxn is sudden and severe

Answer 14

T

Question 15

What are the clinical effects of histamine

Answer 15

Binds to H1 and H2 and causes:
-prurits
-increased vasopermeabiility and vasodilation (cutaneous vasodilation)
-contraction of smooth muscles in airway and GI tract
-nasal and airway mucus production
-gastric acid secretion

Question 16

Tryptase is a protease that is produced by the mast cell can it can cleave C3 and C3a

Answer 16

T

Question 17

Tryptase is only present in mast cell

Answer 17

F
It can be present in other few cells

Question 18

What is the role of heparin

Answer 18

Imp in storing the preformed protease and play a role in production of alfa tryptase

Question 19

Chemotactic factors are for both easinophils and neutrophils

Answer 19

T
-Chemotactic factor of anaphylaxis: easinophilic chemotactic factor
-Inflamm factor of anaphylaxis:
Neutrophil chemotaxis

Question 20

What are common allergens in Hypersen type I

Answer 20

Pollen
Animal dander
Insect bite
Bee sting
Food (nuts and shellfish)
Meds
Plants

Question 21

1st time of exposure leads to a very severe rxn

Answer 21

F
Mild reaction occurs in 1st time of exposure
Repeated exposure leads to a more serious rxn (for IgE to form and bind the surface of mast and basophil)

Question 22

One person is sensitized, even a very limited exposure to a very small amount of allergen can trigger a severe rxn

Answer 22

T

Question 23

Allergic rxns are always very severe

Answer 23

F
Mild or severe
Localized or generalized

Question 24

What are main symps

Answer 24

Allergic rhinitis
Allergic asthma
Allergic gastroenterophathy
Urticaria
Angioedema
Anaphylaxis

Question 25

Allergic rhinitis is the most common clinical expression of atopic hypersensitivity

Answer 25

T

Question 26

Allergic rhinitis: is an IgE mediated allergy localized in the nasal mucosa and conjuctiva

Answer 26

T