Hypersensitivity

Question 1

What is hypersensitivity?

Answer 1

When the normally protective immune system responds abnormally, potentially harming the body. This includes allergy and autoimmunity.

Question 2

What is immunodeficiency?

Answer 2

Partial/full impairment of the immune system, leaving the patient unable to effectively resolve infections or disease

Question 3

What is Primary Immunodeficiency?

Answer 3

Present at birth.
Genetic disorder.
Evident during infancy/childhood.
Classified by which part of immune system affected.

Question 4

What is Secondary Immunodeficiency?

Answer 4

Acquired later in life.
drugs/another disorder e.g., diabetes/hiv
more common than primary immunodeficiency

Question 5

What are the types of hypersensitivity reactions?

Answer 5

Type 1 (immediate)
Type 2 (cytotoxic)
Type 3 (immune-complex mediated)
Type 4 (delayed)
Type 5 (auto immunity)

Question 6

What are type 1 hypersensitivity reactions?

Answer 6

Involve IgE
Anaphylaxis/Asthma

Question 7

What are type 2 hypersensitivity reactions?

Answer 7

IgG, IgM
Transfusion reaction

Question 8

What are type 3 hypersensitivity reactions?

Answer 8

IgG, IgM
SLE

Question 9

What are type 4 hypersensitivity reactions?

Answer 9

T cells
OFG
Organ Rejection

Question 10

What are type 5 hypersensitivity reactions?

Answer 10

Myasthenia Gravis
Pernicious Anaemia

Question 11

What are delayed hypersensitivity reactions?

Answer 11

Orofacial granulomatosis
Erythema multiforme
Aphthous ulceration
Type 3 BMS

Question 12

What is OFG?

Answer 12

A disease limited to the orofacial region characterised by lymphoedema and granuloma formation

Question 13

What are the general features of OFG?

Answer 13

Uncommon
younger age
M:F
50% atopic
crohn’s disease

Question 14

What are clinical features of OFG?

Answer 14

painless lip/facial swelling due to lymphoedema
aphthous-like ulceration
full width gingivitis
buccal mucosa tags
buccal mucosal oedema (cobblestoning)

Question 15

What is the HPC of OFG?

Answer 15

Gradual
Persistent unless treated
Lip swelling, oral ulceration
Persistent with exacerbation
Lower face/lips/buccal mucosa/gingival
no systemic upset

Question 16

What is the pathology of OFG?

Answer 16

Lymphangiectasia
Lymphoedema
Non-caseating granulomata

Question 17

What is the management of OFG?

Answer 17

Specialist treatment
Buccal mucosal biopsy
haematological investigation
patch testing
dietary avoidance
follow up and review

Question 18

What are the identified allergens?

Answer 18

Benzoic acid (preservative)
Cinnamonaldehyde
Chocolate

Question 19

What cases of OFG progress to Crohn’s disease?

Answer 19

Occurs in 6% of patients

Question 20

What is Erythema Multiforme?

Answer 20

Mucocutaneous disorder with an allergic basis

Question 21

What are the general features of Erythema Multiforme?

Answer 21

Uncommon
Adults
M:F
Fatal in some cases

Question 22

What are the clinical features of EM?

Answer 22

Blood crusted lips (primary herpes)
Target lesions may be present on limbs
Widespread confluent oral ulceration
May have cervical lymphadenopathy
pyrexic

Question 23

HPC of EM?

Answer 23

Sudden
10-14 days
multiple coalescing ulcers
skin and oral mucosa

Question 24

Pathology of EM?

Answer 24

Subepithelial bullous disorder

Question 25

Management of EM?

Answer 25

Specialist tx
excludes primary herpetic gingivostomatitis
maintain fluid intake/bed rest
systemic steroids/analgesics
chlorhexidine mw
prevents recurrence

Question 26

What are identified allergens of EM?

Answer 26

Any infection
Drugs eg, sulphonamides
Preservatives e.g, benzoic acid
occasionally no identifiable allergen