3.2.1 Food Allergy Flashcards
A 10-year-old boy presents to the clinic complaining of tongue and mouth itching within a few minutes after eating apples. His mother states that he has not experienced these symptoms with other foods, but they occur every time he eats a fresh apple. He denies systemic symptoms, and the oral symptoms resolve within a few minutes. Other than allergic rhinitis (nasal inflammation) in the spring months, he is healthy. Of the following, you are MOST likely to advise his mother that:
A) allergy skin testing to fresh apples probably will have negative results.
B) cooking the apple will not alter its allergenicity.
C) her son should avoid eating all fruits.
D) her son should avoid milk products.
E) her son’s symptoms are related to his allergic rhinitis.
E) her son’s symptoms are related to his allergic rhinitis
You are the ER physician and you give the child epinephrine injectable, followed by the antihistamine diphenhydramine (Benadryl), and some intravenous fluids. The mother asks you how she is supposed to know if the peanut caused the reaction or if it was something else and you tell her:
A. peanuts don’t cause allergic reactions if they are baked in a cookie.
B. who knows, she should have just given him diphenhydramine (Benadryl) and see if he okay.
C. this was a minor allergic reaction and she should just avoid peanuts in the future.
D. this was anaphylaxis, possibly to peanut, the epinephrine injection likely saved his life, but he needs further testing to find out for sure if it was peanut or another ingredient in the cookie.
D. this was anaphylaxis, possibly to peanut, the epinephrine injection likely saved his life, but he needs further testing to find out for sure if it was peanut or another ingredient in the cookie
Test positive to allergen, may not go on to proceed to a clinical disease
Proven by IgE Immunocap testing, skin testing, or oral challenge
Sensitization
Define a clinical food allergy. What differentiates it from sensization?
Sensitized
-Exposure causes reproducible characteristic IgE-mediated symptoms
What is allergenicity?
Potential to cause allergic reactions
Differentiate intolerance from allergy.
Intolerance
§Your body cannot break down the food
§Lactose intolerance (pain, bloating, diarrhea with milk)
§Eat small amounts – do okay
Allergy
§Your body mistakes that food for something harmful leading to an IgE-mediated reaction
§Immune response – localized or systemic reaction
§Can be triggered by eating a microscopic amount or even with touch or inhalation of the particles
Is the presence of an atopic dz, like latex allergy, associated w/ a higher or lower prevalence of food allergy?
Higher
What are some of the most prevalent food allergies in children?
Cow’s milk, Egg, Peanut
What is the most prevalent food allergies in adults?
Crustaceans (Shellfish)
Differentiate the symptoms/complication associated with IgE-mediated from those of non-IgE/cell-mediated?
What some complications associated with IgE-mediated food allergies?
anaphylaxis, urticaria, angioedema, oral allergy syndrome, acute rhinitis, acute asthma
What is the typical chemical moiety of allergens? What are rarely allergens?
Proteins or glycoproteins (generally heat resistant and acid stable)
Rarely: carbohydrates
Describe the sensitization process on a molecular level (start with allergen and end with mast cell).
allergen -> allergen phagocytosed by DC -> allergen presented to allergen specific T cell -> Th2 -> Release IL-4, IL-5, IL-14 -> B cell stimulation -> Allergen specific IgE production -> IgE binds mast cell via Fc(epsilon)RI
What is released from mast cells during degranulation that causes the symptoms that present in IgE-mediated responses?
Histamines
Leukotrienes
Cytokines
Prostaglandins
PAF
What are some symptoms that people wrongly attribute to IgE-mediated food allergys?
Migraines, Behavioral / Developmental disorders, Arthritis, Seizures, Chronic fatigue, Inflammatory bowel disease
