17. Allergy in childhood Flashcards
Is food intolerance immune mediated?
No - food allergy is
What are the mechanisms in allergy?
- IgE related - immediate, minutes to 2 hrs after ingestion
- Non IgE (Tc): 4 hrs to days
signs and symptoms of IgE- mediated food allergy
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
What is anaphylaxis?
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
investigations in IgE mediated food allergy?
- skin prick test- measure wheal @ 15mins, positive is => 3mm more than saline control
- serum specific IgE
- food challenge
What interferes with the reliability of a skin prick test?
- antihistamines
- recent anaphylaxis - test needs to be >6wks later
What does the size of the SPT tell you?
larger = more likely the IgE reaction will occur, does NOT tell you the severity of the reaction or anything about non-IgE mediated reaction
what is the gold standard for food allergy diagnosis?
oral food challenge
management of generalised allergic reaction?
- antihistamines
- allergy action plan
- identify trigger
Management of anaphylaxis?
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
Adjunctive treatments for anaphylaxis
- ICS and salbutamol
- antihistamines for pruritis
no evidence in life threatening anaphylaxis- ADRENALINE
two doses of epipen
300 mcg (>20kg) 150 mcg (<20kg)
Signs of non IgE allergy
some skin signs, mostly GIT - food protein induced enterocolitis, enteropathy, proctocolitis, eosinophilic oesophagitis
Allergens involved in non IgE food protein induced enterocolitis syndrome and presentation
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
Food protein induced enteropathy signs and cuase
early infancy - cow milk
unwell miserable baby, vomiting, diarrhoea, abd distension, oedema
Food protein induced proctocolitis symptoms and causes?
cause - soy, cow milk, breast feeding.
Well baby, bloody streaks in stools
Acute management of food protein induced enterocolitis syndrome (FPIES)
Involves IV fluid resus if severe (profuse vomiting, diarrhoea)
NOT IM Adrenaline
prognosis of FPIES?
most children outgrow by 3-4 y.o
Diagnosis and management of non IgE related FA
dx - history, oral food challenge management: - avoid allergen - challenge alternative - rechallenge if appropriate in 6-12 mths or 3-4 y.o for FPIES
What is eosinophilic oesophagitis?
A type of non IgE mediated FA involving eosinophilic infiltration of oesophageal mucosa>
regurgitation/vomiting, FTT, difficulty swallowing, epiggastric pain
what is eosinophilic oesophagitis most common caused by?
how is it diagnosed?
causes - dairy, wheat, egg, soy
> gastroscopy and histology of biopsy
> food avoidance, aerosolised corticosteroids
Allergic rhinitis mechanism and management?
IgE mediated avoidance oral antihistamines intranasal corticosteroids allergen immuno therapy
