Food Allergy in Children

Question 1

Overview of pathophysiology of allergies

Answer 1

IgE attach to allergen causes degranulation and release of histamine
Degranulation= rapid release of histamine, tryptase and hydrolase

Later release of inflammatory mediators- prostaglandins, leukotrienes, cytokines

Question 2

Action of histamine

Answer 2

Bronchial smooth muscle contraction,
Vasodilation,
Separation of endothelial cells (responsible for hives),

Question 3

Presentations that are characteristically an allergy

Answer 3

Rapid onset,
Histamine mediated,
Urticaria, itching, angioedema, pallor/ sweating, wheeze,
Improvement with antihistamines

Question 4

Causes of allergies

Answer 4

Food (commonly: milk, eggs, peanut, tree nuts, soya, wheat, fish, seasame),
Bee sting/ wasp,
Drugs,
Exercise,
Idiopathic

Question 5

Symptoms of a mild/moderate and severe allergic reaction?

Answer 5

Mild/ moderate:

• Angioedema,
• Urticaria
• Rash

Severe:

• Angioedema of airway
• Bronchospasm
• Hypotension

Question 6

Investigations of allergies

Answer 6

Skin prick test,
Specific IgE,
Oral food challenge

Question 7

Treatment for idiopathic urticaria +/- angioedema

Answer 7

Non-sedating Antihistamines,
Leukotriene antagonist,
H2 receptor antagonist

Question 8

Presentation of anaphylaxis

Answer 8

Laryngeal oedema,
Hypotension/ collapse,
Bronchospasm, 
Feeling of impending doom, 
Onset in minutes

20% have biphasic reaction 1-8 hours later thus need steroids and hospital admission

Question 9

Risk factors for anaphylaxis

Answer 9

asthma,
stress,
exercise,
viral infection, 
alcohol

Question 10

How does an epipen work?

Answer 10

Reverses peripheral vasodilation,
Increases peripheral vascular resistance,
Improves BP and coronary perfusion,
Decreases angioedema,
Causes bronchodilation,
Decreases release of inflammatory markers

Question 11

Treatment for allergy

Answer 11

Allergen avoidance, 
anti-histamine, 
adrenaline injectors, 
dietary advice,
optimise asthma control

Question 12

What is oral allergy syndrome

Answer 12

Cross reactivity of tree/ plant pollen and foods
Causes itching, mouth swelling, tongue discomfort

Commonly occurs in:
Birch- kiwi, apple, pear, nectarines
Alder- Celery, pear, apple, cherry
Ragweed- Watermelon, banana, cucumber
Mugwort- celery, fennel, carrots
Grass pollen- melon, tomato, orange 

Peeling or cooking often reduces

Question 13

Egg allergy prognosis

Answer 13

Most grow out of by age 5
Tolerate well cooked egg and raw egg last

Use egg ladder:

• Well cooked eg cake
• Lightly cooked eg pancake, omelette, fried egg
• Almost raw eg scambled egg, creme egg