Food Allergy in Children

Understanding Food Allergies

Food allergies can be categorised into two main types based on clinical features that stem from the biological process triggering the allergic reaction. When evaluating a patient, the doctor aims to determine if the reaction is an anaphylactic type or not. It's important to note that even a milder reaction can exhibit anaphylaxis-like features if it follows the same biological pathway. The two primary categories of allergic reactions are:

1. IgE Mediated:

   Characterised by the presence of IgE antibodies in the blood, this type of allergy typically results in rapid reactions, occurring within 5 minutes of exposure to the allergen. The response is not dependent on the dose of the allergen and can manifest as symptoms like hives, facial swelling, wheezing, and even anaphylaxis.

2. Non-IgE Mediated:

   Involving immune system responses that do not primarily involve IgE antibodies, non-IgE reactions often affect the gut, skin, and chest. Symptoms may include eczema, wheezing attacks, and delayed reactions hours to a day after exposure. The severity of non-IgE reactions is usually dose-dependent.

While there is a clear distinction between IgE and non-IgE responses, there are instances where both types of reactions may occur simultaneously.

Common Medical Conditions Related to Non-IgE Reactions

Non-IgE reactions have been linked to various medical issues such as irritable bowel syndrome, eczema, infant colic, and gastro-oesophageal reflux disease. Among children, cow's milk allergy is prevalent, along with soya and non-coeliac wheat allergies.

Diagnostic Approaches

IgE-mediated food allergies are often diagnosed using skin prick tests and specific IgE blood tests. On the other hand, non-IgE allergies are typically identified through dietary exclusion tests. In cases where gut symptoms are ambiguous, procedures like endoscopy can provide valuable insights into potential non-IgE allergic reactions.