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Food allergy series: Take home points

Food allergy series: Food related allergic disorders

There are many types of allergic diseases caused by food.


Oral allergy syndrome:

  • IgE reaction.
  • Causes itching and swelling in the mouth and sometimes the throat.
  • Less than 2% of cases progress to anaphylaxis.
  • Your body mistakes certain raw fruits and vegetables for pollens and reacts.
  • Cooked foods are usually safe in patients with OAS to raw foods.

Asthma and rhinitis:

  • IgE mediated.
  • Caused by inhaling food protein.
  • Most common in infants and children.
  • Can affect adults in specific work environments, like bakeries.
  • Most commonly induced by the eight major food allergens: egg, milk, wheat, soy, peanut, tree nuts, fish and shellfish.

Urticaria and angioedema:

  • IgE mediated.
  • From ingestion or skin contact.
  • Food ingestion causes 20% of acute urticaria cases and 2% of chronic urticaria cases.
  • More common in children.
  • Usually due to eight major allergens.

GI hypersensitivity:

  • IgE mediated.
  • Immediate vomiting in response to major food allergens.

Food associated, exercise induced anaphylaxis:

  • IgE mediated.
  • Ingestion of food in close time proximity to exercising.
  • Exercise may affect the way the GI tract absorbs and digests allergens.
  • Wheat, shellfish and celery most common to provoke this reaction.

Delayed food-induced anaphylaxis to meat:

  • IgE mediated.
  • Occurs several hours after eating.
  • Body makes antibodies to carbohydrate a-gal.
  • A tick bite can cause the body to make these antibodies.
  • Beef, pork and lamb cause reactions.

Atopic dermatitis:

  • IgE and delated cell mediated reactions.
  • 35% reactions in children due to food.
  • May be due to food reactive T cells in the skin.
  • Egg and milk most common.
  • Usually resolves on its own.


Eosinophilic GI disease:

  • IgE and delated cell mediated reactions.
  • Due to eosinophil driven inflammation.
  • Can cause difficult or painful swallowing, weight loss, obstruction and edema.
  • Elimination diets are first line treatments.
  • Endoscopy is diagnostic.


  • Not due to IgE.
  • Usually found in infants.
  • Exposure to food proteins causes chronic vomiting, diarrhea, low energy and poor growth.
  • Cow’s milk, soy, rice and oat are most common offending foods.
  • Cells are more responsive to TNFa and less responsive to TGFb.
  • Usually resolves with age.

Food protein induced allergic proctocolitis:

  • Not due to IgE.
  • Causes mucousy, bloody stools.
  • In response to breast milk containing allergen.
  • Treated by removing food from mother’s diet.


Heiner Syndrome:

  • Not due to IgE.
  • Occurs in infants.
  • Triggered by milk, may be a milk specific IgG reaction.
  • Causes pulmonary infiltration, upper respiratory symptoms, iron deficiency anemia and failure to thrive.

Celiac disease:

  • Not due to IgE.
  • Autoimmune disease causes malabsorption and enteropathy.
  • Caused by reaction to gliadin, gluten protein.
  • Can cause bone abnormalities, IgA deficiency, and other issues.
  • Can present at any age.
  • Is lifelong.

Allergic contact dermatitis:

  • Not due to IgE.
  • Eczema in response to metals in foods.
  • Mostly adults.