Type I Hypersensitivity

Question 1

What is Type I sensitivity

Answer 1

Immediate reaction to re-exposure of an allergen. IgE mediated - mast cells release mediators causing vasodilation, increased vascular permeability and smooth muscle spasm.

Question 2

What infection does atopic dermatitis predispose to?

Answer 2

Staph aureus

Question 3

Typical food allergy allergens

Answer 3

Think protein

Question 4

Ix for Food Allergy

Answer 4

Food diary, skin prick testing, RAST, challenge test

Question 5

Brief pathophysiology of oral allergy syndrome

Answer 5

Exposure to an allergen induces an allergy to food

Question 6

Typical food in latex food allergy

Answer 6

Mostly fruits

Question 7

What is acute urticaria?

Answer 7

IgE mediated reaction. Wheals which resolve within six weeks.

Question 8

Key features of anaphylaxis

Answer 8

Respiratory difficulty + hypotension (shock)

Question 9

Causes of IgE mediated degranulation

Answer 9

Peanut, penicillin, stings, latex

Question 10

Causes of non-IgE mediated degranulation

Answer 10

NSAIDs, IV contrast, opioids, exercise

Question 11

Allergy Ix

Answer 11

Acute: mast cell tryptase (peaks at 1-2 hrs)
1st line: Skin prick
allergen - RAST
protein - component resolved
Food allergy GS → food challenge