Apr5 M2-Food Allergy

Question 1

classification of adverse reactions to food

Answer 1

1. immune mediated (IgE mediated, non IgE)
2. Non immune mediated (food intolerance) (in majority): enzymatic (like lactase def), pharmacologic, toxic (salmonella toxin), undefined

Question 2

example of immune mediated non IgE food reaction

Answer 2

T cells or IgG mediated

IgG mediated example = celiac disease (hypersensitivity to gluten)

Question 3

def of anaphylaxis

Answer 3

2 organ systems involved + drop in BP

Question 4

main food causing anaphylaxis

Answer 4

peanut and tree nut (sentisized upon 1st encounter bc APC-MHC2 to th2 CD4+ then IL4,5,13 then IgE on mast cells for 2nd time)

Question 5

most common allergy in children

Answer 5

peanut (legume in the ground) and tree nut (in the trees) and milk

Question 6

most common allergy in adults

Answer 6

shellfish

Question 7

allergy skin test charact (SPT = skin prick test)

Answer 7

• skin testing where put diff allergens on the back
• done as early as 3 months of age
• topical steroids reduce SPT and late allergen rx

Question 8

ELISA enzyme linked immunoassay used for what in allergy

Answer 8

• put a peanut Ag on a membrane
• take pt serum and put on membrane, IgE for peanut Ag will bind to it if is present
• if something remains after washing = had IgE for peanut allergen

Question 9

how diagnostic is serum IgE assessment with ELISA

Answer 9

• high positive predictive values but not 100% perfect
• can have value above threshold and not be allergic
• history is important

Question 10

gold standard for allergy testing

Answer 10

food challenge

Question 11

2 types of foods-nuts specific reactions

Answer 11

1. severe IgE mediated systemic reactions

2. oral allergy syndrome

Question 12

oral allergy syndrome (also called pollen-food allergy syndrome)

Answer 12

• rxs limited to oral mucosa

- IgE cross reacting with pollen heat labile allergens (destroyed with heat and in the GIT)

Question 13

symptoms in oral allergy syndrome (pollen-food allergy)

Answer 13

• burn in mouth
• 2% can progress to anaphylaxis
• can happen with apples, cherries, peaches

Question 14

atopy def

Answer 14

general tendency to develop IgE against an allergen.

Question 15

cow milk allergy def

Answer 15

• common food allergy caused by caseins (80% of protein mass in milk) and lactglobulin
• often resolves by age 5
• some develop allergic rxs to other foods and get asthma, eczema, allergic rhinitis

Question 16

alternative to cow milk in CMA pts

Answer 16

• hydrolyzed protein formulas of milk (hydrolysates of casein inside)
• work in 90%
• more hydrolyzed = worse taste + more expensive

Question 17

specific shellfish adults are allergic to (most common allergy in adult)

Answer 17

• crustacians (shrimps, lobster, crab)

- mollusks (clams, squids)

Question 18

major allergen in shrimps

Answer 18

tropomyosin (in the muscle) but is different from ours so no autoimmunity

Question 19

2 exercise related causes of anaphylaxis

Answer 19

EIA: exercise induced anaphylaxis
FDEIA: food dependent EIA

Question 20

FDEIA def

Answer 20

onset of anaphylaxis during or soon after exercise, preceded by ingestion of causal food allergen (2h or less before)

Question 21

possible cause of FDEIA

Answer 21

might be bc exercise enhances allergen absorption from the GIT

Question 22

treatment of FDEIA

Answer 22

• if anaphylaxis, epinephrine IM, eliminate the food, carry epipen auto-injector
• avoid exercise 4-6 hrs after eating

Question 23

how can you prevent peanut allergy

Answer 23

introduce peanuts early in the food BY THE MOUTH (not by skin bc not same tolerizing mechanisms as the gut)

Question 24

allergies that we see resolve the most

Answer 24

• milk

- egg