Food and Allergy in Children

Question 1

Does a reaction occur at first exposure to a substance?

Answer 1

No- first time becomes sensitized.
Will have a reaction subsequent times.

Question 2

What does histamine in the body cause to happen?

Answer 2

*Bronchial smooth muscle contraction
* Vasodilation
* Separation of endothelial cells (responsible for hives)
* Pain and itching

Question 3

What can cause allergic reactions?

Answer 3

Food
Environmental allergens e.g. dogs
Drugs
Stings/bite

Question 4

Common food allergies?

Answer 4

Milk
Eggs
Peanut
Tree nuts
Soya
Wheat Fish
Sesame

->but can be allergic to anything

Question 5

When do patients need an epipen?

Answer 5

If breathing difficulty or collapse

->urticaria and rash, just avoid allergen and take anti-histamines if in contact with allergen.

Question 6

Investigations for food allergies?

Answer 6

Skin prick test
Specific IgE
Oral food challenge

Question 7

What are downsides to skin prick testing?

Answer 7

Stop antihistamines for 48hrs before
Cannot do on broken skin
Over-interpretation of positive results*
Avoid in dermatographism - drawing on skin produces hives

->* good when negative as almost certain not allergic. However, can be false positives so can say you are allergic to something you are not

Question 8

Do anti-histamines need to be stopped before doing specific IgE testing?

Answer 8

No

Question 9

When are specific IgE results unreliable?

Answer 9

If patient has eczema

Question 10

Gold standard for testing food allergens?

Answer 10

Oral food challenge

->basically patient eats susposed allergen

Question 11

If patients only have urticaria as a reaction symptom, what investigations are done?

Answer 11

None

->just avoid triggers

Question 12

If patients only have angioedema as a reaction symptom, what investigations are done?

Answer 12

Hereditary Angioedema C4 and C1 Esterase Inhibitor

Question 13

Treatment of urticaria and angioedema?

Answer 13

Avoid triggers
Antihistamines
High Dose Antihistamines +/- second antihistamine
Leukotriene Antagonist
Corticosteroids (3-5 days)
Tranexamic Acid
Anti IgE Monoclonal antibody (Omalizumab) in
children over 7 years of age (rare)

Question 14

Symptoms of anaphylaxis?

Answer 14

• Laryngeal Oedema
• Hypotension/collapse
• Bronchospasm
• Feeling of impending doom
• Onset usually in minutes

->later the onset, less severe the reaction

Question 15

Management of egg allergy?

Answer 15

Very common, most outgrow
Egg ladder, start with very well cooked egg at about one year old