GI Food Allergy

Question 1

Food Allergy

Answer 1

an adverse health effect arising from a specific immune response that occurs reproducibly on exposure to a given food.

Question 2

Food intolerance

Answer 2

symptoms that may be related to ingestion of a good, but not a TRUE allergy

Question 3

Food Oils

Answer 3

usually not allergenic as most proteins are removed in processing.

Question 4

Major allergenic foods >85% of food allergy

Answer 4

Kids: milk, egg, soy, wheat, peanut, tree nuts
Adults: peanut, tree nuts, shellfish, fish, fruits and vegetables.
-Proteins or glycoproteins (almost always): generally heat resistant, acid stable.
- Carbohydrate allergens (rare): reports of adult-onset mammalian meat allergy triggered by galactose-alpha-1,3-galactose (alpha-gal)

Question 5

Mechanism of Food Allergy

Answer 5

• Protein digestion, antigen processing, some antigen enters blood.
  -IgE mediated: mast cell and Histamine.
• Non-IgE mediated: TNF-alpha, IL-5.

Question 6

IgE Mediated Adverse Food Reactions

Answer 6

• Systemic (Anaphylaxis)
• Oral Allergy Syndrome
• Immediate GI allergy
• Asthma/rhinitis
• Urticaria
• Morbilligorm rashes and flushing
• Contact urticaria

Question 7

Non-IgE Mediated Adverse Food Reactions

Answer 7

• Food Protein-Induced Enteropathy
• Food Protein-Induced Proctocolitis
• Dermatitis herpetiformis
• Contact dermatitis

Question 8

Adverse Food Reactions (inbetween)

Answer 8

• EOE
• Eosinophilic gastritis
  -Eosinophilic gastroenteritis (EoG)
• Atopic dermatitis

Question 9

Diagnosis of Food Allergy

Answer 9

• Best test: clinical history
• Food challenge
• allergy testing only help with IgE mediated disorders.

Question 10

Allergic Proctocolitis (CMPI) biopsy

Answer 10

• Patchy eosinophilic infiltrate (severity is variable).
• Neutrophilic cryptitis can be seen (not to extent of infectious colitis or IBD)
• No chronic mucosal changes

Question 11

FPIES

Answer 11

• repetitive vomiting ~2 hours s/p ingestion
• diarrhea ~5 hours s/p ingestion
• Dehydration, lethargy, acidemia, hypotension, methemoglobinemia, occasional hypoalbuminemia and FTT
• Dairy is most common cause. usually occurs in first year of life

Question 12

FPIES Management

Answer 12

• IVF boluses
• Supportive care 24-48 hours
• Epinephrine typically not helpful
• AVOID the food triggers!

Question 13

FPIES: not IgE mediated

Answer 13

Diagnostic gold standard: oral food challenge
majority become tolerant to inciting foods by age 3-5 years.

Question 14

Eosinophilic Gastroenteritis

Answer 14

eosinophils can invade mucosa, muscular layer, serosa (obstruction/ascites)
CBC: elevated WBC, elevated peripheral eosinophils, decreased serum albumin
weight loss, malabsorption, ill appearing. must exclude IBD
treatment: prednisone. Immunosuppressive (6MP/MTX). In the future: biologics: Anti IL-5