Allergy and Immunology

Question 1

Food Allergy (I)

Answer 1

Allergy: adverse immune response to food
Intolerance: NON-immunological reaction to food e.g. due to lack of certain enzymes
Food allergy types
IgE mediated:
- Quick onset reaction (includes anaphylaxis)
- Can impact several systems e.g. skin, respiratory, GI
- Can be life-threatening
Non-IgE mediated:
- Often more delayed reaction
- Tends to be younger children
- More likely to present with present with GI symptoms e.g. vomiting, cramps, loose stool

Question 2

Food Allergy (II)

Answer 2

Most common food allergies: Cow’s milk, eggs, peanuts, shellfish
Risk factors include:
- Atopic eczema
- Family history (allergy or atopy)
Presentation of IgE mediated allergy may include:
- Skin: urticaria, itching, flushing, angioedema
- Respiratory: wheeze, cough, breathlessness, sneezing
- GI: abdominal pain, nausea, vomiting
- General: hypotension, tachycardia, bradycardia (in a more anaphylaxis type picture)

Question 3

Food allergy assessment

Answer 3

Food Allergy assessment may include:
Food diary
Elimination trial
Skin prick tests (introduce lots of different allergens to the skin, reassess after 15 minutes)
Serum specific IgE allergy testing for different foods
(both above are sensitive but not specific, so need to go with strong history)
May need supervised oral food challenge (secondary care) if:
- Uncertain diagnosis or to see if child has ‘outgrown; allergy

Question 4

Food allergy management

Answer 4

Food Allergy Management:
- Food avoidance
- Dietician input
- Antihistamines if needed
- If baby with cow’s milk allergy:
Breastfed: discuss food avoidance advice with mother
Bottle-fed: discuss hypoallergenic formula or milk substitute
- Refer to allergy specialist if
History of severe allergic reaction, anaphylaxis
Comorbidities e.g. asthma
Other concerns e.g. growth

Question 5

Anaphalaxis management (I)

Answer 5

ABCDE
Remove trigger
High flow oxygen
IM Adrenaline as per age:
* Adults: 0.5mg (0.5ml of 1 in 1000)
* >12 years: 0.5mg (0.5ml of 1 in 1000)
* >12 years (if small) 0.3mg (0.3ml of 1 in 1000)
* 6-12 years 0.3mg (0.3ml of 1 in 1000)
* Up to 6 years 0.15mg (0.15ml of 1 in 1000)

Question 6

Anaphalaxis management (II)

Answer 6

Ongoing Management:
- IV fluid challenge: e.g. 500-1000ml Hartmann’s or 0.9% saline (adult)
- Chlorpheniramine IM/IV (after initial resuscitation)
- Hydrocortisone IM/IV (after initial resuscitation)
- Symptomatic treatment e.g. salbutamol/ipratropium
- Regular monitoring e.g. BP, O2 saturations, ECG

Follow-up:
- Offer referral to all patients with suspected anaphylaxis
- Offer 2x adrenaline-autoinjectors for future
- Consider wearing advisory device e.g. bracelet

Question 7

Other allergy testing

Answer 7

Atopy (e.g. allergic rhinitis) - skin prick testing
Contact dermatitis - patch testing