Allergy

Question 1

What type of allergic reactions are there? Describe the differences

Answer 1

IgE mediated - this type has a rapid onset (within an hour), it is histamine mediate and will improve with anti-histamines. Will resolve quickly, even severe reactions will settle within 12-24hrs.

Non- IgE mediated

Question 2

How can an Ig E mediated allergic reaction present?

Answer 2

Within an hour

Urticaria
erythema
Angioedema
Pallor
Sweating
Wheeze

Question 3

How would a reaction be classified as severe?

Answer 3

Angioedema of the airway (not just lips and eyes) causes stridor. This is anaphalyaxis. They can also have bronchospasm and hypotension.

Question 4

How are allergic reactions investigated?

Answer 4

Sometimes skin prick test- easy, cheap and results within 20 minutes
Specfic IgE
Oral food challenge (in hopsital not at home)

Question 5

Who needs an adrenaline pen/epipen?

Answer 5

Severe systemic reaction
Those whos allergen can not be easily avoided
Those with high risk allergens e.g. nuts that also have asthma
If react to trace amounts of allergen
Continuing risk of anaphylaxis e.g. exercise induced

Question 6

How is an allergic reaction treated?

Answer 6

AVOID ALLERGEN

Epipen/adrenaline
Antihistamine
Leukotriene antangonist
Corticosteroids
Tranexamic acid (used in angiodema but not commonly)
Anti IgE monoclonal antibody (Omalizumab) in children over 7 years old.

Question 7

Describe egg allergy and it’s treatment

Answer 7

Most common allergy in infancy

Usually mild
Majority grow out of it by 5 years old.

Treatment:
Avoid and then reintroduce using egg ladder after about 6 months, start with cooked egg in sponge then work your way up to eventally raw egg after years.

Question 8

Describe milk allergy

Answer 8

Cow’s milk allergy is very common in infancy

Investigation:
Skin Prick testing
Specific IgE
Therapeutic exclusion trail with reintroduction after 6 weeks

Question 9

Describe IgE mediated Cow’s milk allergy and its treatment

Answer 9

Rapid onset
Anaphylaxis, angioedema
Vomiting
diarrhoea

Maternal avoidance of Cow’s milk if breast feeding and Calcium + vit D supplements
EHF (hydrolysed) formula
AA formula if EHF not tolerated

Soya milk if >1 years old and above not tolerated

Question 10

Describe Non IgE mediated Cow’s milk allergy and it’s treatment

Answer 10

Not histamine based, slower reaction.

Presents vairably:
diarrhoea, vomiting, irritability, infantile eczema, bloating, bleeding PR

Investigations: dietary management/ avoidance trail

Improves with withdrawal of milk protein.