Oral Allergies

Question 1

What is allergy?

Answer 1

When immune system reaction in exaggerated or inappropriate response to extrinsic antigen

Question 2

What is auto-immunity?

Answer 2

When immune system responds in exaggerated or inappropriate way to intrinsic antigen

Question 3

What is hypersensitivity?

Answer 3

When immune system responds in exaggerated or inappropriate way resulting in harm

Question 4

Are allergies and autoimmunity types of hypersensitivity?

Answer 4

Yes

Question 5

What are different forms of hypersensitivity?

Answer 5

Antibody mediated

Cell mediated

Question 6

What types of hypersensitivity are antibody mediation?

Answer 6

Type 1, 2 and 3

Question 7

What hypersensivity is cell mediated?

Answer 7

Type IV

Question 8

What is type I hypersensivity

Answer 8

Immediate/ anaphylaxis

Question 9

What is type II hypersensitivity?

Answer 9

Cytotoxic

Question 10

What is type III hypersensivity?

Answer 10

Immune complex

Question 11

What is type IV hypersensitivity?

Answer 11

Delayed

Question 12

How is type I hypersensitivity mediated?

Answer 12

IgE

Question 13

When get symptoms of type I hypersensitivity?

Answer 13

Immediate

Question 14

What happens in type I hypersensitivty

Answer 14

Allegens causes antigen response causing which causes mast cell degranulations causing histamine and enzyme release

Question 15

What does release of histamine cause?

Answer 15

Vascular dilation 
Increased vascular permeability = oedema
Bronchospasm 
Urticarial rash 
Increased nasal/ lacrimal secretions

Question 16

Common causes of type I response

Answer 16

Hay fever
Asthma
Allergies: penicillin, laxtex etc

Question 17

How to diagnosis allergy for type I hypersensitivity?

Answer 17

Wheel and flare

Allergy applied using prick test and skin response is fast

Question 18

What is wheel and flare?

Answer 18

Wheel - extravasation of serum into skin due to histamine

Flare - erythematous red patch caused axon response

Question 19

Issue w/ wheel and flare test?

Answer 19

Can get late phase 6hrs after due leukocyte infiltrate and oedema

Question 20

How manage type I hypersensitivity?

Answer 20

Adrenaline
Anti-histamine
Corticosteroid

Question 21

Use of corticosteroids in type I management?

Answer 21

Dampen immune response

Question 22

What happens on first exposure to allergy

Answer 22

Antigen bind to B cell
B cell turn to plasma cell –> ab released
Cytokine environment causes plasma clells to secrete IgE ab
IgE enters blood which rapidly bind to mast recoprtos
IgE displayed on Fc receptors on mast cell

Question 23

How can IgE be used to see if someone is predisposed to allergic reaction?

Answer 23

They will have high serum levels of IgE

Question 24

What happens on second exposure to antigen?

Answer 24

Have specific IgE
Antigen cross-link Fc rector on mast cell
Transmit intra-cellular signal causing mast cell degranulation
Histamine released

Question 25

What is a type II hypersensitivity?

Answer 25

Antibody mediated - antibodies target self-antigens usually IgG or IgM = cell damage and inflammation

Question 26

Mechanism type II?

Answer 26

Antibodies target self-antigens | Autoantibodies activate T cells/ neutrophils/ macrophages causing inflammation of complement

Question 27

What does complement activation in type II cause?

Answer 27

Caused inflammation and cells death via MAC

Question 28

What is MAC

Answer 28

Membrane attack complex

Question 29

What is mechanism of type III?

Answer 29

Immune complex form between antibodies and antigens

Question 30

What happens to immune complex formed in type III?

Answer 30

Deposits in lining blood vessel/ lung - causes complement activation and neutrophil binding = inflammatory and vascular permability

Question 31

Give example of type III hypersensitivity?

Answer 31

Erythema multiforme | SLE - systemic lupus erythematosis

Question 32

What is type IV hyperseniviity mediated by?

Answer 32

Cell- mediated | Mediated by T cellsq

Question 33

When is type IV delayed?

Answer 33

Response is cellular - slow to develop and resolve

Question 34

When see type IV sensitivity

Answer 34

Delayed hypersensitivity responses Contact dermatitis Lichenoid reactions OLP

Question 35

Mechanism of type IV?

Answer 35

Extrinsic antigen enter oral Dendritic cells intercept and process antigen Antigen stimulated Langerhans cells to migrate to draining lymph node Also stimulate keratinocytes to release TNF

Question 36

What happens in draining lymph nodes in type IV?

Answer 36

Langerhan cell process antigen and presents to T cell circulating in lymph node Antigen specific T cell becomes activated - proliferation and re-circulation to oral mucosa

Question 37

What happens in oral mucosa in type IV?

Answer 37

Epithelial cells activated to secrete TNF TNF induces VCAM-1 expression on endothelium Allows T cells to bind VCAM-1 Interaction between T cells and epithelium = cytokine release Cytotoxic T cells kill basal keratinocytes

Question 38

What see histology of type IV hypersensitivity?

Answer 38

Dense band T cells in connective tissue

Question 39

2 mechanism in which T cells induce apoptosis?

Answer 39

Fas-mediated | Peforin/ granzyme B

Question 40

What is perforin?

Answer 40

Pore forming molecule

Question 41

Type IV summary?

Answer 41

Langerhan cells move from epidermis to lymph nodes They present antigen to CD4 T cells T cells move to mucosa to secrete TNF Causes expression VCAM1 Secretion pro-inflammatory cytokines which damage tissue

Question 42

When is tissue damage seen in type IV?

Answer 42

12 hours

Question 43

3 main issues w/ allergies in dentistry?

Answer 43

Drug allergies Dental material allergies Latex allergy

Question 44

What type of reaction is a drug allergy?

Answer 44

Type I

Question 45

Are LA allergies common?

Answer 45

Not true allergies - preservative been removed | Most reaction vasovagal due intra-vascular injection

Question 46

What type of reactions are those to dental materials?

Answer 46

Type IV - response usually chronic and localised

Question 47

What metals are likely to cause type IV responses?

Answer 47

Nickle | Mercury - lichenoid reaction

Question 48

Alternative to latex gloves?

Answer 48

Nitrile