Food allergy and eosinophilic gastrointestinal disorders

Food allergy management

Optimal management of food allergy is complex and multifaceted. Management of food allergy includes ensuring proper diagnosis, monitoring for the emergence of natural tolerance, screening for nutritional and psychosocial issues, and educating the patient and family on living with food allergies across childhood. Education must encompass successfully avoiding the trigger food, recognizing and treating allergic reactions, and navigating living with food allergies. Allergists can help families prepare for specific situations, such as working with daycares, schools, after-school activities and camps, traveling, and dining out. In addition, psychosocial issues such as anxiety and bullying should be addressed, and counseling with regard to emerging therapies discussed. Managing children with food allergies requires continual follow up with regard to these issues, and the needs of families will change over time. Allergists can guide the family as the child grows and transitions to adulthood when managing food allergy.

Classification of adverse food reactions

Foods can induce adverse reactions by a variety of mechanisms. An understanding of the characteristic signs and symptoms and the related mechanisms of adverse food reactions allows the clinician to efficiently diagnose and treat patients. Adverse reactions to foods can be classified based on whether there is a nonimmunologic or immunologic basis for symptoms. Food intolerance, or a nonimmunologic reaction, includes a range of responses to foods that result primarily from an individual's intrinsic inability to metabolize a component of the food, e.g., lactose sugar in dairy products. Other nonimmunologic adverse reactions may be attributed to food toxins or pharmacologic properties pharmacologic properties of foods themselves. Immunologic adverse reactions, in contrast, involve immune responses to food and are termed food allergy. Food allergy may further be categorized based on the underlying immunopathophysiology as immunoglobulin E (IgE) mediated, non-IgE mediated, or cell mediated. Some chronic allergic responses involve a combination of immune mechanisms. This review provides a general classification system for adverse food reactions and describes specificconditions.

Immunoglobulin E-mediated food allergy diagnosis and differential diagnosis

Food allergies consist of aberrant immunologic, typically immunoglobulin E mediated, reactions that involve food proteins. A clinical history with regard to the suspected food, temporal associations, the duration of symptoms, characteristic symptom complex, and reproducibility in some cases is the key to making an accurate diagnosis. The differential diagnosis includes, for example, other immunologic adverse food reactions, nonimmunologic adverse food reactions, and reactions that involve nonfood items. Skin and blood immunoglobulin E testing for the suspected food antigen can aid the diagnosis in the context of a supportive clinical history. Immunoglobulin E testing for food components may further enhance diagnostic accuracy. Novel testing modalities are under development but are not yet ready to replace the current paradigm. Thus, double-blinded placebo controlled oral food challenge is considered the criterion standard of testing, although unblinded oral food challenges are usually confirmatory.

Food protein-induced proctocolitis and enteropathy

Non-IgE (immunoglobulin E) mediated gastrointestinal food allergies include several separate clinical entities, including food protein-induced allergic proctocolitis (FPIAP) and food protein-induced enteropathy (FPE). Although FPIAP and FPE both primarily affect the gastrointestinal tract, their presentations are vastly different. FPIAP presents with bloody stools in otherwise healthy infants, whereas FPE presents with chronic diarrhea, vomiting, malabsorption, and hypoproteinemia. These both typically present in infancy and resolve by early childhood. Although the presenting signs and symptoms may be different, management is similar in that both require avoidance of the suspected causal food.