Food allergy

Last reviewed: 7 May 2023
Last updated: 25 Nov 2022



History and exam

Key diagnostic factors

  • presence of risk factors
  • milk, egg, nut, fish, shellfish, wheat, or soya ingestion
  • reproducible symptoms
  • flushing, urticaria, or angio-oedema of the skin
  • sneezing, rhinorrhoea, or nasal congestion
  • dyspnoea, tachypnoea, wheezing, coughing, or cyanosis
  • hoarseness, stridor, or sense of choking
  • nausea and vomiting
  • abdominal cramping or bloating
  • diarrhoea
  • conjunctival injection or lacrimation
  • periorbital oedema
  • abrupt onset of symptoms
  • reaction caused by small amount of food
  • presence of other allergic disease
  • laryngeal oedema
More key diagnostic factors

Other diagnostic factors

  • tachycardia or bradycardia
  • reaction exacerbated by exercise or exertion
  • alcohol or medication ingestion before reaction
  • cardiac arrhythmia
  • hypotension
Other diagnostic factors

Risk factors

  • family history of food allergy
  • atopic dermatitis
  • newborn
  • perinatal peanut oil exposure
More risk factors

Diagnostic investigations

1st investigations to order

  • in vitro IgE specific immunoassay
  • skin prick testing
More 1st investigations to order

Investigations to consider

  • food challenges
  • component-resolved diagnostics
More investigations to consider

Emerging tests

  • atopy patch testing

Treatment algorithm


anaphylactic reaction

cutaneous symptoms




following stabilisation



A. Wesley Burks, MD
A. Wesley Burks

Curnen Distinguished Professor and Chair

Department of Pediatrics

University of North Carolina

Chapel Hill



AWB receives grant support to his institution from the National Institutes of Health and the Burroughs Wellcome Fund; royalties from UpToDate; consulting honorariums from Astella Pharma Global Development, Allergy Therapeutics (UK) Ltd, DBV Technologies, Kaléo, N-Fold, LLC, ALK-Abelló Inc, and UKKO Inc, as well as Aimmune Therapeutics, Consortia TX Inc, and Prota Therapeutics for his service on their respective Scientific Advisory Boards. AWB owns stock in Allertein and Mastcell Pharmaceuticals. These interests do not directly relate to the article but are being shared for full disclosure. AWB is an author of references cited in this topic.

J. Andrew Bird, MD

Associate Professor

Department of Pediatrics

Division of Allergy and Immunology

University of Texas Southwestern Medical Center




JAB has received personal fees from Abbot, grants and personal fees from Aimmune, personal fees from AllerGenis, personal fees from Allergy Therapeutics, personal fees from Before Brands, grants and personal fees from DBV Technologies, grants and personal fees from FARE, personal fees from HAL Allergy, grants and personal fees from Novartis, personal fees from Nutricia, personal fees from Prota Therapeutics, grants from Astellas, grants from Genentech, grants from NIH-NIAID, grants from Regeneron; and Vedanta Biosciences, Independent Study Monitor (uncompensated).

Peer reviewers

Justin Skripak, MD

Assistant Professor of Pediatric Allergy and Immunology

Mount Sinai School of Medicine

New York



JS declares that he has no competing interests.

Hugh A. Sampson, MD

Professor of Pediatrics

Mount Sinai School of Medicine

New York



HAS holds a 4% interest in a biotech company, Allertein Pharmaceuticals LLC, which is developing an engineered recombinant protein vaccine for peanut allergy, and 45% interest in a virtual company, Herbal Springs LLC, that holds a patent application on an herbal product for treating asthma and another for treating food allergy. HAS is an author of a number of references cited in this topic.

Adam Fox, MA(Hons) Cantab., MSc, MBBS, DCH, FRCPCH, FHEA, Dip. Allergy

Consultant and Honorary Senior Lecturer in Paediatric Allergy

Evelina Children's Hospital

Guy's & St Thomas' Hospitals NHS Foundation Trust




AF declares that he has no competing interests.

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    Food allergy: what is it?

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