Immunological disorders: (a) food allergy and hypersensitivity

Food allergy diagnosis is based on allergy-focused clinical history taking and discriminate use of test modalities such as skin prick testing, serum specific immunoglobulin E (IgE) testing, and formal food challenge. It can be considered a form of hypersensitivity and is pathophysiologically distinct from intolerance reactions and other nonimmune-mediated reactions. Food allergies can be broken down immunologically into three broad groups: IgE mediated, non-IgE mediated and mixed. The clinical features of IgE-mediated food allergy are very stereotyped, with the rapid onset, usually within minutes, of perioral urticaria and angioedema, which may propagate to bronchospasm and cardiovascular changes. Once the diagnosis of IgE-mediated food allergy is secure, initial management focuses on education of the individual to avoid the allergen, ensuring dietary substitutions are in place to maintain dietary completeness for both micronutrients and macronutrients.