W12-L1: Food Allergy Flashcards
What is a Food allergy?
a consistent adverse immune response to the proteins in a food
What are the 2 types of Food Allergies?
- Immunoglobulin E (IgE) mediated reaction
- Non-IgE mediated reaction
What is an
Immunoglobulin E (IgE) mediated reaction?
B Cells in the immune system make special (IgE) antibodies
* potentially life-threatening:, immediate, systemic, intense response to a very small amount of that allergen
What is a Non-IgE mediated reaction?
where other parts of the body’s immune system react, causing symptoms, but does not involve the IgE antibody (believed to be T-cell mediated) .
- Very specific: Small intestine & large intestine: Food protein induced enterocolitis syndrome (FPIES) and Eosinophilic Esophagitis (EoE) – swallowing disorder
What are examples of
Non-IgE mediated reaction?
Food protein-induced enterocolitis syndrome (FPIES)
- Small intestine & large intestine:
Eosinophilic Esophagitis (EoE)
- swallowing disorder
PRIORITY ALLERGENS
What % of Canadians have Food Allergies?
- 7.5% of Canadians self report having at least 1 food allergy
- It is estimated that food allergies affect 3-4% of adults in westernized countries; as many as 6% of young children
Why are Food Allergies on the rise?
“hygiene hypothesis”, cleaner and more sanitized environments, and their immune systems are shifting toward developing allergic responses to certain foods and away from fighting germs or infections
What are the risk factors for food allergy?
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- Age: more common in young children than in older children or adults.
- Family history: If your parent or sibling has a food allergy a persons likelihood of having a food allergy is increased
- Another food allergy: Presence of a food allergy, means someone is at greater risk for developing another
- Related medical conditions: risk is increased if with existing allergic disease such as asthma, eczema, or hay fever.
What are the ways to diagnose Food Allergies?
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- Gold standard: Oral food challenge (OFC)
- Blood: Food specific IgE test
- Skin prick test
What is the Oral food challenge (OFC)?
Gold standard: Oral food challenge (OFC): positive double-blind, placebocontrolled food challenge and patient history
What is the Blood: Food specific IgE test?
Response is divided into classes (I –V):
- Class 1 and II: low level of allergen sensitization and, often, with a low likelihood of a clinical reaction
- Greater = higher degrees of sensitization and generally correlate with IgE-mediated clinical reactions upon allergen exposure
What is the Skin prick test?
placing a drop of allergen onto the surface of the skin, & then
pricking through it to introduce the allergen into the top layer of the skin
What are the treatments for Food Allergy?
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- Avoidance and carry an epi pen
- Oral immunotherapy – preschoolers
- Sublingual immunotherapy (SLIT)
What is Oral immunotherapy – preschoolers?
- Someone is allergic to the food as confirmed by blood & OFC
- Given a small amount of a food to which they are allergic under medical supervision – eaten at home for 1 – 4 weeks
- Then return for medically supervised increase in quantity every two weeks – “up dosing phase”. Can last for >6 months
- About 80% of people reach a maintenance dose (300mg protein) and are classified as “desensitized” and in the maintenance phase
- After 1 year of maintenance doses, 4/5 patients pass an oral challenge test - tolerate a much higher dose of 4,000 mg of protein
- Most information currently is available for eggs, milk and peanuts
What is Sublingual immunotherapy (SLIT)?
- Involves placing small amounts of food allergens under the tongue – 2mg initially
- High risk older children and adolescents
