17. Allergy in childhood

Question 1

Is food intolerance immune mediated?

Answer 1

No - food allergy is

Question 2

What are the mechanisms in allergy?

Answer 2

• IgE related - immediate, minutes to 2 hrs after ingestion

- Non IgE (Tc): 4 hrs to days

Question 3

signs and symptoms of IgE- mediated food allergy

Answer 3

cutaneous: erythema, pruritis, urticaria, angioedema
GIT: lip and tongue swelling, nausea, colicky abdo pain, vomiting, diarrhoea
respiratory: nasal congestion, hoarseness, cough, chest tightness, wheeze
CV: tachycardia, hypotension, dizziness, fainting

Question 4

What is anaphylaxis?

Answer 4

Any acute onset illness with typical skin features (urticaria/erythema/angioedema) plus respiratroy +/- CV +/- sever GIT symptoms.
It’s a clinical diagnosis - difficult/noisy breathing, tongue swelling, tighness in throat, dizziness/collapse

Question 5

investigations in IgE mediated food allergy?

Answer 5

• skin prick test- measure wheal @ 15mins, positive is => 3mm more than saline control
• serum specific IgE
• food challenge

Question 6

What interferes with the reliability of a skin prick test?

Answer 6

• antihistamines

- recent anaphylaxis - test needs to be >6wks later

Question 7

What does the size of the SPT tell you?

Answer 7

larger = more likely the IgE reaction will occur, does NOT tell you the severity of the reaction or anything about non-IgE mediated reaction

Question 8

what is the gold standard for food allergy diagnosis?

Answer 8

oral food challenge

Question 9

management of generalised allergic reaction?

Answer 9

• antihistamines
• allergy action plan
• identify trigger

Question 10

Management of anaphylaxis?

Answer 10

IM 0.01mg/kg adrenaline (max 0.5 mg) into anterior-lateral thigh.
repeat after 5 mins if not improving.

Airway: nebulised adrenaline, early intubation
B: high flow O2
C: supine, elevate legs. IV - large gauge cannula
Fluid: 20ml/kg 0.9% saline fluid bolus, adrenaline influsion 0.05-1 mcg/kg/min

Question 11

Adjunctive treatments for anaphylaxis

Answer 11

• ICS and salbutamol
• antihistamines for pruritis
  no evidence in life threatening anaphylaxis- ADRENALINE

Question 12

two doses of epipen

Answer 12

300 mcg (>20kg)
150 mcg (<20kg)

Question 13

Signs of non IgE allergy

Answer 13

some skin signs, mostly GIT - food protein induced enterocolitis, enteropathy, proctocolitis, eosinophilic oesophagitis

Question 14

Allergens involved in non IgE food protein induced enterocolitis syndrome and presentation

Answer 14

cow milk/soy milk/rice/legumes/oats
2hrs after ingestion> acutely unwell baby, profuse vomiting, abdomen distension, bloody diarrhoea, +/- CVS collapse (pallor, floppiness)
= food protein induced enterocolitis syndrome

Question 15

Food protein induced enteropathy signs and cuase

Answer 15

early infancy - cow milk

unwell miserable baby, vomiting, diarrhoea, abd distension, oedema

Question 16

Food protein induced proctocolitis symptoms and causes?

Answer 16

cause - soy, cow milk, breast feeding.

Well baby, bloody streaks in stools

Question 17

Acute management of food protein induced enterocolitis syndrome (FPIES)

Answer 17

Involves IV fluid resus if severe (profuse vomiting, diarrhoea)
NOT IM Adrenaline

Question 18

prognosis of FPIES?

Answer 18

most children outgrow by 3-4 y.o

Question 19

Diagnosis and management of non IgE related FA

Answer 19

dx - history, oral food challenge
management:
- avoid allergen
- challenge alternative
- rechallenge if appropriate in 6-12  mths or 3-4 y.o for FPIES

Question 20

What is eosinophilic oesophagitis?

Answer 20

A type of non IgE mediated FA involving eosinophilic infiltration of oesophageal mucosa>
regurgitation/vomiting, FTT, difficulty swallowing, epiggastric pain

Question 21

what is eosinophilic oesophagitis most common caused by?

how is it diagnosed?

Answer 21

causes - dairy, wheat, egg, soy
> gastroscopy and histology of biopsy
> food avoidance, aerosolised corticosteroids

Question 22

Allergic rhinitis mechanism and management?

Answer 22

IgE mediated
avoidance
oral antihistamines
intranasal corticosteroids
allergen immuno therapy