Allergy Flashcards
What is an allergen?
Any substance stimulating production of IgE or a cellular immune response
Usually a protein
What is sensitivity?
A normal response to a stimulus
What is hypersensitivity?
An abnormally strong response to a stimulus
What is sensitisation?
The production of IgE antibodies after repeated exposure to an allergen
What is allergy?
A hypersensitivity reaction initiated by specific immunological mechanisms
Can be IgE or non-IgE mediated
What is atopy?
The tendency to produce IgE antibodies in response to ordinary exposure to potential allergens
Strongly assosciated with asthma, rhinitis, eczema and food allergy
What is anaphylaxis?
A serious allergic reaction with bronchial, laryngeal and cardiovascular involvement
Onset is rapid and can cause death
What is the allergic march? (atopic march)
Different allergies more prevelent with age
Food allergy and eczema often affect younger patients
As they become older will be less effected by these but more affected by asthma and rhinitis
What are the 3 questions to ask if a patient presents to primary care with suspected allergy?
- Is this milk allergy?
- Is this food induced anaphylaxis?
- Is this allergy?
What is milk allergy? What are some of the symptoms?
Allergy to milk seen in babies
- Feeds slowly
- Vomiting after feeds
- Arches back and pulls legs up after feeds
- Very uncomfortable passing stools
What is the cut of point (age) for diagnosing milk allergy?
12 months
After this will not be milk allergy
What are the two types of presentation of milk allergy?
Immediate onset (40%) - IgE mediated:
- symptoms affecting skin, respiratory and GI tracts
- Symptoms of urticaria, cough, wheeze, vomiting and diarrhoea
- Can cause anaphylaxis and be fatal
Delated onset (60%)- non IgE mediated:
- predominantly multiple GI symptoms
- Difficult to diagnose: similar presentation to colic and reflux
What are the 14 major allergens?
What is food allergy?
An adverse health effect arising from specific immune respone that occurs reproducibly on exposure to a certain food
IgE and non IgE mediated
What is food intolerance?
Numerous adverse responses to foods that do not involve an immune response
How do IgE and non IgE mediated food allergies differ in their presentation?
(symptom onset, common foods, presenting age, natural history)
How do symptoms differ between IgE mediated and non IgE mediated food allergy?
What is food associated exercised induced anaphylaxis?
Food that triggers anaphylaxis only if ingestion is followed (within 2 hours) by exercise
what is pollen food syndrome?
Pruritis and mild oedema of the oral cavity associated with hay fever
Seen when eating raw fruit and veg
What is proctocolitis?
Passage of bright red blood in mucousy stolls in otherwise asymptomatic infants
(seen in milk allergy)
What is enterocolitis?
Multiple and varying GI symptoms seen in delated onset allergy including:
- refusal
- persistent vomiting
- abdominal cramps
- loose and frequent stools
- constipation
What is eosinophilic oesophagitis?
Symptoms from oesophageal inflammation and scarring feeding disorders.
- reflux symptoms
- vomiting
- dysphagia
- food impaction
What is food proteins induced enterocolitis syndrome?
Primary affects infants - delayed onset to food allergy
- profuse vomiting
- lethargy
- pallor
- possibly shock
- diarrhoea (25%)
Describe the food allergy march
