Food allergies

• What is a typical food allergy reaction?

  Exposure to allergen leads to acute reaction (itching, facial swelling & urticaria, can be anaphylaxis)
• What type of hypersensitivity reaction is triggered by food allergies?

  Type 1
• What is important to cover in a history for allergy?

  Timing after exposure to allergen

  Previous & subsequent exposure & reaction to allergen

  Symptoms of rash, swelling, breathing difficulty, wheeze & cough

  Previous Hx of atopic conditions & allergies
• What are the RFs of food allergy?

  FHx

  Atopic dermatitis

  Perinatal peanut oil exposure
• What are the signs & symptoms of food allergy?

  Reproducible symptoms

  Flushing, urticaria or angioedema of skin

  Sneezing, rhinorrhea or nasal congestion

  Nausea & vomiting

  Tachypnoea

  Abdo cramping or bloating

  Diarrhoea

  Periorbital oedema

  Presence of other allergic disease
• What are the Inx of food allergy?

  Obs

  Full Hx & examination

  IgE specific immunoassay

  Food challenge testing

  Skin prick testing
• What are the DDx of food allergy?

  Atopic dermatitis

  Urticaria

  Acute asthma exacerbation

  Gastroenteritis

  IBS

  IBD
• What are the possible complications of food allergy?

  MI

  Failure to thrive

  Anaphylaxis

  Death
• What is the management of food allergy?

  Manage anaphylaxis

  Avoid food causing intolerance
• Pathophys - food allergy

  IgE antibodies specific to certain epitopes in food allergen bind to receptors on mast cells & basophils -> allergen crosslinks bound IgE antibodies on mast cells & basophils -> triggers release of cytokines, chemokines, histamine, prostaglandins, leukotrienes -> vasodilation, smooth muscle contraction, mucous secretion