allergy

Question 1

Features of an allergy

Answer 1

• Rapid onset
• Histamine mediated reactions
• Urticaria, itching, angioedema, pallor/sweating, wheeze
• Improvement with antihistamines
• Relatively quick resumption of symptoms

Question 2

Aetiology

Answer 2

• Food
• Contact e.g. bee/ wasps
• Environmental allergen
• Drugs e.g. amoxycillin
• Exercise
• Idiopathic

Question 3

Types of food which causes allergies?

Answer 3

o	Milk – not IgE 
o	Hen’s egg 
o	Peanut- LEGUME FAMILY- closer to a pea/ legume
o	Tree nuts 
o	Soya 
o	Wheat 
o	Fish 
o	Sesame

Question 4

Severity of an allergy and presentations?

Answer 4

Severity 
-Mild/moderate
o	Angioedema 
o	Urticaria/rash 
-Severe: 
o	Angioedema of the airway 
o	Bronchospasm 
o	Hypotension

Question 5

Investigations?

Answer 5

• Skin prick test
• Specific IgE
• Oral food challenge

Question 6

Pros and cons of a skin prick?

Answer 6

Pros:
o	Easy
o	Quick 
o	Non-invasive 
o	Immediate results 
o	Cheap 
o	Negative SPT is an excellent predictor for negative IgE mediated food reaction in patients with anaphylaxis 

Cons

• Need to stop anti-histamines
• Should not do on broken skin
• Risk of anaphylaxis
• Dermatographism : drawing on skin which leads to urticaria
• Over interpretation of positive results

Question 7

Pros and cons of Specific IgE

Answer 7

Pros:
oNo need to stop antihistamines
oNo risk of reaction

Cons:
oExpensive and invasive
oDelay in obtaining results – about 2 weeks
oLess sensitives and specific than SPT -more false positives
oHighly unreliable results

Question 8

What is the GOLD standard for Investigation?

Answer 8

Oral food challenge

Question 9

What is you can’t find an allergen?

Answer 9

• As needed: non sedating anti-histamines
• Regular non-sedating anti-histamines
• Leukotriene antagonist or H2 receptor antagonist

Question 10

Risk factors for anaphylaxis

Answer 10

• Asthma
• Stress
• Exercise
• Viral infection
• Alcohol

Question 11

Treatment for anaphylaxis?

Answer 11

Adrenaline pens

Question 12

Effects of adrenaline?

Answer 12

• Reverses peripheral vasodilatation
• Increases peripheral vascular resistance
• Improves BP and coronary perfusion
• Decreases angioedema
• Causes bronchodilation
• Decreases the release of inflammatory mediators

Question 13

Treatment for allergy

Answer 13

• Allergen avoidance
• Anti-histamines
• Dietary advice
• Optimise asthma control
• Adrenaline for anaphylaxis

Question 14

What is an allergy to fruit and veg also known as and how is it managed?

Answer 14

ORAL ALLERGY SYNDROME 
o	Peeling or cooking reduces symptoms 
o	Antihistamine 
o	Avoid 
o	Does not cause anaphylaxis

Question 15

Egg allergy

Answer 15

• More common in children
• Most children grow out of it by age 5
• Mild and benign
• Tolerate well cooked eggs first then raw: egg ladder

Question 16

Presentation of anaphylaxis

Answer 16

• Hypotension
• Larangeal oedema
• Bronchospasm
• Feeling of impending doom

Question 17

Genetic component

Answer 17

NOT INHERITED

• Higher risk with parental atopy
• Concordance in allergy in twins