Allergy and Skin

Question 1

Main mediator in Type 1 hypersensitivity?

Answer 1

IgE

Question 2

Main mediator in Type 2 hypersensitivity

Answer 2

IgG mediated cytotoxic hypersensitivity

Question 3

Main mediator in Type 3 hypersensitivity

Answer 3

Immune complex

Question 4

Main mediator in Type 4 hypersensitivity

Answer 4

Cell mediated

Question 5

Skin example of type 4 hypersensitivity?

Answer 5

Allergic contact dermatitis, erythema, rash

Question 6

Skin manifestations of type 1 hypersensitivity

Answer 6

urticaria, angioedema

Question 7

Most common type of hypersensitivity associated with blood transfusions

Answer 7

Type 2

Question 8

Most common conditions associated with type 3 hypersensitivity

Answer 8

necrotising vasculitis, glomerulonephritis,
rheumatoid arthritis,
SLE

Question 9

What are the time limits for an allergic reaction to be classed as type 1?

Answer 9

seconds to 2 hours after allergen exposure

Question 10

What makes the IgE that eventually binds to mast cells?

Answer 10

B cells

Question 11

How long does urticaria typically last?

Answer 11

2-6 hours

Question 12

Is angioedema pitting or non-pitting?

Answer 12

non-pitting

Question 13

1st and 2nd line tests for type 1 hypersensitivity reactions

Answer 13

1. IgE test

2. Prick test

Question 14

1st line for type 4 hypersensitivity

Answer 14

Patch test

Question 15

What to do if prick test is negative but you’re still convinced the patient has an allergy?

Answer 15

Challenge test

Question 16

MoA of sodium cromoglycate?

Answer 16

Blocks mast cell activation thus stabilising them

Question 17

1st, 2nd and 3rd line treatment for food allergy?

Answer 17

1. antihistamine eg chlorphenamine
2. prednisolone if antihistamine takes over 10min to work
3. Adrenaline if still systematically unwell

Question 18

How does adrenaline work?

Answer 18

Vasoconstricts blood vessels to bring blood pressure back to normal

Question 19

Why is coeliac disease non-allergic?

Answer 19

Not mediated by IgE

Question 20

Usual time frame of type 4 hypersensitivity?

Answer 20

24-48hrs

Question 21

first line test for allergic contact dermatitis

Answer 21

patch test

Question 22

Examples of irritant contact dermatitis?

Answer 22

Nappy rash, lip lick dermatitis, detergent, cosmetics, cement

Question 23

Why is irritant contact dermatitis different to allergic contact dermatitis?

Answer 23

Not immune mediated, the irritants traumatise the skin directly and don’t require prior sensitisation

Question 24

Best management for contact dermatitis?

Answer 24

AVOIDANCE, emollients, topical steroids, UV phototherapy, immunotherapy

Question 25

How common is food allergy in children with moderate/severe eczema?

Answer 25

1 in 5

Question 26

Main signs of anaphylaxis?

Answer 26

angiodema,
colicky pain, 
tachycardia
diarrhoea,
vomiting, 
tachycardia, 
hypotension

Question 27

Skin manifestations of type 3 hypersensitivity?

Answer 27

purpura, rash

Question 28

Skin manifestations of type 2 hypersensitivity?

Answer 28

pemphigus/pemphygoid