9. Food allergy

https://doi.org/10.1016/j.jaci.2005.05.048Get rights and content

Food allergy, defined as an adverse immune response to food proteins, affects as many as 6% of young children and 3% to 4% of adults. Food-induced allergic reactions are responsible for a variety of symptoms involving the skin, gastrointestinal tract, and respiratory tract and might be caused by IgE-mediated and non–IgE-mediated (cellular) mechanisms. Our understanding of how food allergy represents an abrogation of normal oral tolerance is evolving. Although any food can provoke a reaction, relatively few foods are responsible for the vast majority of significant food-induced allergic reactions: milk, egg, peanuts, tree nuts, fish, and shellfish. A systematic approach to diagnosis includes a careful history, followed by laboratory studies, elimination diets, and often food challenges to confirm a diagnosis. Many food allergens have been characterized at a molecular level, which has increased our understanding of the immunopathogenesis of food allergy and might soon lead to novel diagnostic and therapeutic approaches. Currently, management of food allergies consists of educating the patient to avoid ingesting the responsible allergen and to initiate therapy in case of an unintended ingestion.

Section snippets

Pathogenesis

Food allergy might result from a breach in oral tolerance to foods while they are being ingested (class 1 food allergy) or might result from sensitization to allergens apart from their exposure to the gastrointestinal tract, recognized instead during respiratory exposure (class 2 food allergy).11, 12 Class 1 food allergy typically occurs to food proteins that are generally stable to digestion that are encountered by infants or children during a presumed window of immunologic immaturity. In

Clinical disorders

The disorders can be classified on the basis of interrelated immunologic causes and the organ system or systems affected (Table I). The features of each disorder are described in detail in recent reviews.1, 3, 4 Various gastrointestinal food-induced allergic disorders share symptoms but can be differentiated by patterns of illness and diagnostic tests (Table II).1, 24, 25, 26 Additional gastrointestinal symptoms (colic, constipation, and reflux) have sometimes been attributed to food allergy.

Diagnosis

The evaluation begins with a thorough history and physical examination to consider a broad differential diagnosis (Table I). The history should determine the possible causal food or foods, quantity ingested, time course of reaction, ancillary factors (exercise, aspirin, and alcohol), and reaction consistency. Reason dictates that a food ingested infrequently is more likely responsible for an acute reaction than one previously tolerated. Symptoms such as urticaria after ingestion of a food are

Management

The primary therapy for food allergy is to avoid the causal food or foods. New food-labeling laws effective in January 2006 require simple terms to indicate the presence of major food allergens (eg, “milk” instead of “casein”). Patients and caregivers should be encouraged to obtain medical identification jewelry, taught to recognize symptoms, and instructed on using self-injectable epinephrine and activating emergency services. Comprehensive educational materials are available through

References (60)

  • M. Kalliomaki et al.

    Probiotics and prevention of atopic disease: 4-year follow-up of a randomised placebo-controlled trial

    Lancet

    (2003)
  • E. Pohjavuori et al.

    Lactobacillus GG effect in increasing IFN-gamma production in infants with cow's milk allergy

    J Allergy Clin Immunol

    (2004)
  • H. Breiteneder et al.

    A classification of plant food allergens

    J Allergy Clin Immunol

    (2004)
  • H. Breiteneder et al.

    Molecular properties of food allergens

    J Allergy Clin Immunol

    (2005)
  • D. Mittag et al.

    Ara h 8, a Bet v 1-homologous allergen from peanut, is a major allergen in patients with combined birch pollen and peanut allergy

    J Allergy Clin Immunol

    (2004)
  • S.H. Sicherer

    Clinical implications of cross-reactive food allergens

    J Allergy Clin Immunol

    (2001)
  • H.A. Sampson et al.

    AGA technical review on the evaluation of food allergy in gastrointestinal disorders

    Gastroenterology

    (2001)
  • S. Bischoff et al.

    Gastrointestinal food allergy: new insights into pathophysiology and clinical perspectives

    Gastroenterology

    (2005)
  • M.W. Yocum et al.

    Epidemiology of anaphylaxis in Olmsted County: a population-based study

    J Allergy Clin Immunol

    (1999)
  • S.A. Bock et al.

    Fatalities due to anaphylactic reactions to foods

    J Allergy Clin Immunol

    (2001)
  • H.A. Sampson

    Food allergy. Part 2: diagnosis and management

    J Allergy Clin Immunol

    (1999)
  • C. Ortolani et al.

    Comparison of results of skin prick tests (with fresh foods and commercial food extracts) and RAST in 100 patients with oral allergy syndrome

    J Allergy Clin Immunol

    (1989)
  • H.A. Sampson et al.

    Relationship between food-specific IgE concentrations and the risk of positive food challenges in children and adolescents

    J Allergy Clin Immunol

    (1997)
  • H.A. Sampson

    Utility of food-specific IgE concentrations in predicting symptomatic food allergy

    J Allergy Clin Immunol

    (2001)
  • T. Boyano-Martinez et al.

    Prediction of tolerance on the basis of quantification of egg white- specific IgE antibodies in children with egg allergy

    J Allergy Clin Immunol

    (2002)
  • C. Garcia-Ara et al.

    Specific IgE levels in the diagnosis of immediate hypersensitivity to cows' milk protein in the infant

    J Allergy Clin Immunol

    (2001)
  • M. Osterballe et al.

    Threshold levels in food challenge and specific IgE in patients with egg allergy: is there a relationship?

    J Allergy Clin Immunol

    (2003)
  • T.T. Perry et al.

    The relationship of allergen-specific IgE levels and oral food challenge outcome

    J Allergy Clin Immunol

    (2004)
  • W.G. Shreffler et al.

    Microarray immunoassay: association of clinical history, in vitro IgE function, and heterogeneity of allergenic peanut epitopes

    J Allergy Clin Immunol

    (2004)
  • J.M. Spergel et al.

    The use of skin prick tests and patch tests to identify causative foods in eosinophilic esophagitis

    J Allergy Clin Immunol

    (2002)
  • Cited by (0)

    View full text