Allergy and the Skin

Question 1

Type 1 allergy?

Answer 1

• Immediate reaction
• Skin contact, inhalation, ingestion & injection
• Consistent reaction with every exposure

Question 2

How sensitization works?

Answer 2

Peanut activates dendritic cells which goes onto activate
|
Peanut specific T cells 
|
Th2
| 
B cells
| 
Mast cells the degranulate

Question 3

Anaphylaxis?

Answer 3

Severe life threatening generalized or systemic hypersensitivity reaction.
-Rapidly developing, life threatening problems involving airway, breathing and or circulation

Question 4

Clinical presentation of Type 1 hypersensitivity?

Answer 4

Urticaria- itchy, hives

Angioedema- localized swelling subcutaneous tissue/mucous membranes, non itchy

Question 5

Investigations for allergy?

Answer 5

• History
• Specific IgE (RAST)
• Skin prick or prick-prick testing
• Challenge test
• Serum mast cell tryptase level

Question 6

Pros of skin prick/prick-prick testing?

Answer 6

• Cheap and quick
• Specificity & sensitivity 90+%
• Low anaphylaxis risk

Question 7

What is challenge test?

Answer 7

Challenging patient with allergen

-risk of anaphylaxis is higher

Question 8

Management of allergy?

Answer 8

• Allergen avoidance
• Prevent affects of mast cell activation (anti-histamine)
• Anti-inflammatory agent (corticosteroids)
• Adrenaline autoinjector (for anaphylaxis)
• Block mast cell activation (mast cell stabilisers) eg sodium cromoglycate
• Immunotherapy
• Medic alert bracelet
• Info & education

Question 9

What is an adrenaline autoinjector for?

Answer 9

Anaphylaxis

Question 10

Examples of non-allergic reaction?

Answer 10

Coeliac’s

Eosinophilic gastroenteritis

Question 11

Difference between Non allergic and allergic reactions?

Answer 11

Non allergic is not mediated by IgE

• Direct mast cell degranulation (morphine, aspirin, NSAIDs)
• Metabolic (lactose intolerance)
• Toxic

Question 12

Type iv allergy?

Answer 12

Delayed hypersensitivity
Antigen specific
T cell mediated
Allergic contact dermititis

Question 13

How to test for hypersensitivity iv?

Answer 13

Patch testing

Question 14

Irritant contact dermatitis?

Answer 14

Non-immunological process

• Contact with agents that abrade, irritate, and traumatize skin directly
• Pattern depends on exposure

Question 15

Atopic eczema is?

Answer 15

Endogenous

Question 16

Management of general dermatitsis?

Answer 16

Allergen/irritant avoidance 
Allergen/irritant minimisation 
-Emollients 
Topical steroids
UV phototherapy 
Immunosuppressants