Food allergies

Food allergies are immune-mediated adverse reactions to specific foods. In immunoglobulin E (IgE)-mediated food allergy, the immune system mistakenly identifies a food protein as harmful and produces IgE antibodies in response.

Food allergy is a growing public health concern, affecting around 8% of children and 10% of adults in developed countries.

How are food allergies characterized?

In sensitized individuals, symptoms typically occur within minutes to 2 hours of exposure. Clinical presentations vary from cutaneous symptoms (e.g., urticaria, pruritis) to gastrointestinal (e.g., abdominal pain, vomiting) and respiratory involvement (e.g., wheezing, dyspnea).

Severe cases may result in anaphylaxis, characterized by airway swelling and multisystem involvement.

Non–IgE-mediated and mixed food allergies, which primarily affect the gastrointestinal tract, are less well defined and often present with delayed symptoms.

How are food allergies diagnosed?

Diagnosis requires a detailed clinical history, supported by skin prick testing or serum-specific IgE testing. When results are inconclusive, oral food challenges – conducted under medical supervision – remain the gold standard.

What are the most common food allergens?

Common triggers include milk, eggs, peanuts, tree nuts, soy, wheat, fish, and shellfish.

What are the standard approaches to managing food allergies?

Management focuses on allergen avoidance and patient education. For individuals at risk of anaphylaxis, prescription and training in the use of epinephrine auto-injectors are essential.

What pharmacologic treatments are recommended for food allergies?

Antihistamines may be used for mild symptoms, while epinephrine is used first-line for anaphylaxis. Omalizumab shows promise in reducing reactions to multiple allergens. Oral immunotherapy with defatted peanut protein powder is approved for peanut allergy in children.

Oral and sublingual immunotherapy are emerging options, requiring specialist oversight because of the risk of adverse reactions.

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