Allergy

Question 1

what is the main function of the immune response

Answer 1

Defence against external and internal antigens

Question 2

what are consequences of the immune response

Answer 2

destruction of antigens

incidental collateral tissue damage

Question 3

what is a hypersensitivity reaction

Answer 3

immune response that causes collateral damage to the self with exaggeration of normal immune mechanisms

Question 4

what is type 1 mediated hypersensitivity

Answer 4

ALLERGY

an IgE mediated response

Question 5

how quickly do type 1 hypersensitivity reactions take place

Answer 5

within minutes and up to 2 hours after exposure

Question 6

how can type 1 allergic reactions present

Answer 6

urticaria
angioedema
asthma
anaphylaxis

Question 7

Investigations for type 1 hypersensitivity reactions

Answer 7

Specific IgE blood tests
Skin prick test
Challenge test (only if SPT is negative)
serum mast cell trypase level (rises during anaphylaxis)

Question 8

whats type 4 hypersensitivity

Answer 8

delayed hypersensitivity - antigen specific T cell mediated

Question 9

example of type 4 hypersensitivity

Answer 9

allergic contact dermatitis

Question 10

how quickly does a type 4 reaction occur

Answer 10

24-48 hours

Question 11

how does contact allergic dermatitis present

Answer 11

reaction is present only at the site of exposure to allergen

Question 12

Investigations for type 4 reactions

Answer 12

patch testing

Question 13

how is patch testing done

Answer 13

allergens prepares in wells
places on back skin
taken of after 48 hours
reactions check at 48 and then 96 hours

Question 14

how to manage contact allergic dermatitis

Answer 14

allergen/irritant avoidance 
allergen/irritant minimisation 
emollients 
topical steroids 
UV phototherapy 
Immunosupressants

Question 15

what is contact irritant dermatitis

Answer 15

non-immunological dermatitis
does not require sensitisation
pattern depends on exposure
agents abrade, irritate and traumatise skin directly