Allergy and the skin Flashcards Preview

Year 2 > Allergy and the skin > Flashcards

Flashcards in Allergy and the skin Deck (43):
1

What is hypersensitivity?

An exaggerated immune response which causes damaged to oneself

2

How can hypersensitivity be classified?

Type 1 - IgE mediated
Type 2 - IgG mediated cytotoxic
Type 3 - Immune complex mediated
Type 4 - Delayed cell mediated

3

What are allergic reactions?

Immune system response to a normally harmless substance

4

What is an allergen?

Substance which causes an immune reaction

5

What is the theory behind the increasing prevalence of allergy?

Hygiene hypothesis

6

What is the time frame of a type 1 allergic reaction?

Between minutes to two hours

7

What routes of exposure can cause a type 1 allergic reaction?

Inhalation
Ingestion
Skin contact
Injection

8

What is the main history feature of a type 1 allergic reaction?

Consistent reaction every time

9

What are the common ingested allergens?

Nuts
Seafood

10

What are the common inhaled allergens?

House dust mite
Pollen

11

What are the common skin contact allergens?

Animal dander
Latex

12

What are the common injected allergens?

Bee
Medication

13

How does a type 1 allergic reaction present?

Urticaria
Angioedema
Wheezing/asthma
Anaphylaxis

14

How does urticaria present?

Itchy
Wheals
Lasts 2-6 hours but less than 24 hours

15

What is angioedema?

Swelling of the subcutaneous tissues or mucous membranes

16

How does angioedema present?

Swelling
Not itchy
Non-pitting

17

What is anaphylaxis?

Life threatening general or systemic hypersensitivity reaction

18

How does anaphylaxis present?

Rapidly developing
Airway (oedema)
Breathing (tachypneoa)
Circulation (hypotension)
Associated skin/mucosal changes

19

How is suspected type 1 hypersensitivity investigated?

Specific IgE (RAST)
Skin prick
Challenge test (rare)
Serum mast cell tryptase (during anaphylaxis)

20

What are the benefits and drawbacks of skin prick testing?

Cheap
Quick
Specific
Sensitive

Small anaphylaxis risk

21

When would challenge testing be undertaken?

Skin prick testing negative
Last resort

22

How is type 1 allergy managed?

Avoidance
Anti-histamines
Corticosteroids (anti-inflammatory)
Adrenaline autoinjector (anaphylaxis)
Sodium chromoglycate
Immunotherapy

23

What is the dose of an adrenaline autoinjector in children and adults?

150ug
300ug

24

How many adrenaline autoinjector pens should a patient have at the one time?

2

25

Is coeliac an allergic condition?

No

26

Is lactose intolerance an allergic condition?

No

27

What is the timeframe for a type 4 hypersensitivity reaction?

Reaction occurs within 24-48 hours of exposure

28

Is type 4 hypersensitivity specific to a particular antigen?

Yes

29

Which type of cells are involved in type 4 hypersensitivity?

T cells

30

What type of skin reaction is mediated by type 4 hypersensitivity?

Allergic contact dermatitis

31

How do type 4 hypersensitivity skin reactions present?

Specific to allergen contact/exposure site/pattern
Mostly eczematous reaction

32

How are type 4 hypersensitivity skin reactions investigated?

Patch testing

33

How is a patch test carried out?

Allergens placed in wells
Wells applied to back and removed after 48 hours
Back is checked at 48 hours and 96 hours

If photo-allergens are suspected two wells must be done one exposed to UV and one not

34

What are the three main categories of dermatitis?

Atopic
Irritant
Allergic

35

Is irritant contact dermatitis an immunologically mediated process?

No

36

How does irritant contact dermatitis happen?

Skin comes into contact with something which directly irritates, abrades or traumatises it

37

How does irritant contact dermatitis present?

Depends on the pattern of exposure

38

Give two examples of irritant contact dermatitis

Lip lick dermatitis
Nappy rash

39

What is atopic eczema associated with?

Asthma
Hayfever/allergic rhinitis

40

How is atopic eczema distributed?

Flexural

41

How is psorisasis distributed?

Extensor

42

How is irritant dermatitis managed?

Avoidance or modification

43

How is dermatitis treated?

Emollients
Steroids
UV phototherapy
Immunosupressants

Decks in Year 2 Class (72):