Immunoglobulin E (IgE)-mediated Food Allergy

Background

• Immunoglobulin E-mediated food allergy is a specific, and reproducible, immune response occurring after exposure to an allergenic food which results in adverse health effects.
• There are various clinical spectrums of IgE-mediated food reactions including anaphylaxis, food-dependent exercise-induced, acute urticaria, acute angioedema, and oral allergy syndrome.
• Risk factors may include genetic factors such as asthma or atopic dermatitis and environmental factors such as delayed ingestion of food allergens or altered immune response.
• There are 2 phases to an allergic reaction: immediate (IgE binding to food antigens with cross-linking to mast cells) and late (influx of eosinophils).
• The prognosis for allergies to milk, egg, soy, and wheat is that they generally resolve in childhood, while ones to peanut, tree nut, fish, and shellfish often persist into adulthood.
• An infant diet of exclusive breastfeeding for the first 4-6 months of life, the introduction of solids at 4-6 months of age, and the use of hydrolyzed infant formula, if not breastfeeding, may help to reduce allergies.
• Early egg or peanut introduction into the infant diet may decrease the risk of egg or peanut allergy.

Evaluation

• The clinical presentation of immunoglobulin E-mediated allergic disease may include cutaneous, respiratory, or gastrointestinal findings; it may also present as anaphylaxis.
• A complete history and physical examination is essential when evaluating for a possible food reaction.
• Diagnostic testing should only be performed in patients with a convincing clinical history and may include:
  • skin prick test
  • serum-specific IgE testing
  • oral food challenge
  • elimination diet
  • component-resolved diagnostics
  • atopy patch testing

Management

• The mainstay in the management of immunoglobulin E-mediated food allergy involves allergen avoidance.
• Acute treatment of allergic reactions may include airway management, IV fluids, epinephrine, anti-histamines, steroids, albuterol, or racemic epinephrine depending on the severity of the reaction.
• Dietary counseling, emergency management plans, and referral to an allergist may be needed depending on reaction severity.
• Sublingual and oral immunotherapy may each reduce the risk of persisting food allergy but are not recommended for widespread clinical use.
• While there are no medications, supplementations, or screening tests recommended for the prevention of IgE-mediated food allergies at this time, this is an area of active research.