Immunoglobulin E (IgE)-mediated food allergy.

Food allergy is defined as an adverse immunologic response to a food. Immunoglobulin E (IgE)-mediated reactions to foods are associated with a broad range of signs and symptoms that may involve any of the following body systems: the skin, gastrointestinal tract, respiratory tract, and cardiovascular system. IgE-mediated food allergy is a leading cause of anaphylaxis.

Introduction to immunology and immune disorders.

The body has a collection of physical barriers to prevent infection, but once these are overcome, we rely on our immune systems to protect us against a wide variety of infections. The complex mechanisms through which this is achieved are grouped into two lines of defense called the "innate" and "adaptive" immune systems. The innate immune system provides a rapid and tailored response to infection or injury often associated with inflammation.

Non-immunoglobulin E-mediated food allergy.

Non-immunoglobulin E (IgE)-mediated food allergies are characterized by delayed gastrointestinal (GI) manifestations that occur after exposure to an inciting food protein; they include food protein-induced allergic proctocolitis (FPIAP), food protein-induced enteropathy (FPE), and food protein-induced enterocolitis syndrome (FPIES). Although the exact mechanisms underlying these disorders are not well understood, non-IgE-mediated food allergies likely represent a spectrum of disease with shared pathophysiological processes. Typically, these non-IgE-mediated food allergies begin in infancy or early childhood, although FPIES can present across the lifespan, with increasing reports in adults in recent years.

Primary prevention of food allergy: beyond early introduction.

Food allergy typically begins early in life and persists as a lifelong condition. Delayed introduction of allergenic foods followed by years of hesitancy to introduce these foods early may have contributed to the increase in food allergy prevalence in recent decades. Most infant feeding guidelines focus on the importance of early introduction of allergenic foods in infants at around age 4-6 months.

Eosinophilic esophagitis.

Eosinophilic esophagitis (EoE) is an atopic condition of the esophagus that has become increasingly recognized. Diagnosis of the disorder is dependent on the patient's clinical manifestations and must be confirmed by histologic findings on esophageal mucosal biopsies. The epidemiology, pathophysiology, diagnosis, treatment, and prognosis of EoE are discussed in this review.