3. Food Allergy Flashcards
What is the definition of an allergy?
A hypersensitivity reaction initiated by specific immuno- logical mechanisms. This can be IgE mediated (e.g. peanut allergy) or non-IgE mediated (e.g. milk allergy).
What is an allergen?
Any substance stimulating the production of IgE or a cellular immune response. Usually a protein, but can be carbohydrates (much less common).
What is sensitivity?
Normal response to a stimulus.
What is hypersensitivity?
An abnormally strong response to a stimulus.
What is sensitisation?
Production of IgE antibodies after repeated exposure to an allergen.
What is atopy?
A tendency to produce IgE antibodies in response to ordinary exposure to potential allergens. Strongly associated with asthma, rhinitis, eczema and food allergy.
What is anaphylaxis?
A serious allergic reaction with bronchial, laryngeal and cardiovascular involvement that is rapid in onset and can cause death.
Which allergies tend to present in younger children? And which in older?
Younger - eczema, food allergy.
Middle - asthma.
Older - rhinitis.
How is a food intolerance different to a food allergy?
Food intolerance is an adverse response to food that does not involve the immune system. Food allergy is an adverse health affect arising from a specific immune response that occurs on food exposure.
What is urticaria with angioedema?
Acute hives and swelling with respiratory but not gastrointestinal or CVS symptoms.
What is food-associated exercise induced anaphylaxis?
Food triggers anaphylaxis only if ingestion is followed temporally (within 2 hours) by exercise.
What is pollen food syndrome?
Pruritus and mild oedema confined to the oral cavity (lips, tongue, mouth and throat) uncommonly progressing. Associated with hay fever (raw fruit and vegetables)
What is protocolitis?
Passage of bright red blood in mucousy stools in otherwise asymptomatic infants. (milk, through breast feeding)
What is enterocolitis?
Multiple and varying gastrointestinal symptoms including feed refusal, persistent vomiting, abdominal cramps, loose and frequent stools and constipation. (milk, eggs, wheat).
What is eosinophilic oesophagitis?
Symptoms from oesophageal inflammation and scarring of feeding disorders, reflux symptoms, vomiting, dysphagia and food impaction. (milk, eggs, wheat).
What is food protein-induced enterocolitis syndrome?
Primarily affects infants. Profuse vomiting leading to pallor, lethargy and possibly shock; diarrhoea in 25%. Increased WCC, so careful isn’t sepsis. (milk, soya, rice, wheat, meat).
Is immediate onset or delayed onset food allergy IgE mediated?
Immediate - IgE mediated.
Delayed - non IgE mediated.
Give 3 presentations of immediate-onset (IgE mediated) food allergy
Urticaria/angioedema.
Anaphylaxis.
Food-associated exercise induced anaphylaxis.
Pollen food syndrome.
Give 3 presentations of delayed-onset (non-IgE mediated) food allergies
Protocolitis.
Enterocolitis.
Eosinophilic oesophagitis.
Food protein-induced enterocolitis syndrome.
Which food allergies are diagnosed more in infancy, early childhood, and adolescence?
Infancy - milk, egg, peanut.
Early childhood - soya, wheat, tree nuts, fish, shellfish, kiwi, sesame.
Adolescence - fresh fruit and vegetables (pollen food syndrome).
What common allergens are less allergenic when cooked?
Cow’s milk, egg white, apples.
Why can food processing (eg by cooking with other ingredients such as wheat) make an allergen non-allergenic?
Food processing destroys conformational epitopes which were causing the reaction.
What type of food allergy has immediate symptom onset?
Immediate (5-30 minutes) - IgE mediated.
Delayed (hours or days) - non IgE mediated.
Do IgE mediated or non-IgE mediated food allergies have more vague symptoms?
Non-IgE mediated more vague and common with other conditions.
