Food allergy is an adverse immune response to food proteins. Most reactions are from peanut, tree nuts, milk, egg, fish, shellfish, wheat, and soya. Symptoms usually appear within 20 minutes of ingestion and nearly always within 2 hours.
Symptoms and signs may vary from pruritus and mild cutaneous eruption to severe anaphylactic respiratory, gastrointestinal, or cardiovascular (e.g., hypotensive) manifestations.
Epinephrine (adrenaline) given by intramuscular injection is the treatment of choice for severe systemic symptoms (anaphylaxis); lesser reactions are managed with a range of therapies from simple withdrawal of suspected food allergen to oral antihistamines.
Patients should be encouraged to obtain medical identification jewellery, be knowledgeable of the incipient signs and symptoms of an allergic reaction, be trained how to use an epinephrine (adrenaline) auto-injector, and know how to activate emergency response services.
Food allergy is an adverse immune response to food proteins.
Reactions may be either IgE-mediated, non-IgE-mediated, or mixed IgE-mediated/non-IgE-mediated reactions. IgE-mediated reactions to food are primarily considered here.
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
- conjunctival injection or lacrimation
- periorbital oedema
- abrupt onset of symptoms
- reaction caused by small amount of food
- presence of other allergic disease
- laryngeal oedema
Other diagnostic factors
- tachycardia or bradycardia
- reaction exacerbated by exercise or exertion
- alcohol or medication ingestion before reaction
- cardiac arrhythmia
- family history of food allergy
- atopic dermatitis
- perinatal peanut oil exposure
1st investigations to order
- in vitro IgE specific immunoassay
- skin prick testing
Investigations to consider
- food challenges
- component-resolved diagnostics
- atopy patch testing
A. Wesley Burks, MD
Curnen Distinguished Professor and Chair
Department of Pediatrics
University of North Carolina
AWB receives grant support to his institution from the National Institutes of Health, Food Allergy Research & Education, and Allergen Research Corporation; royalties from UpToDate; consulting honorariums from Aravax, Astella Pharma Global Development, DBV Technologies and N-Fold, LLC, as well as Aimmune Therapeutics, Consortia TX, Inc., Intrommune Therapeutics, and Prota Therapeutics for his service on their respective Scientific Advisory Boards. AWB has consulted for the following companies (which are all now expired): Biomerica, Inc., Evelo Biosciences/Epiva, Genentech, Insys Therapeutics, PPD Development, Sanofi US Services, Valeant Pharmaceuticals North America, LLC, LEK Consulting, LLC, Hycor Biomedical. AWB has received payments for speaking at the Gordon Research Conferences, the Pediatric Allergy and Asthma Meeting, and the American College of Allergy Asthma and Immunology. AWB is a minority stockholder of both Allertein and Mastcell Pharmaceuticals stock. 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
Department of Pediatrics
Division of Allergy and Immunology
University of Texas Southwestern Medical Center
JAB has received personal fees from Food Allergy Research and Education, personal fees and non-financial support from American College of Allergy, Asthma and Immunology, grants from Nestle Health Sciences, personal fees from Nutricia North America, personal fees from Pharm-Olam International LTD, personal fees and other from Pfizer Pharmaceuticals, grants, personal fees and non-financial support from Aimmune Therapeutics, personal fees from Prota Therapeutics, personal fees from Allergy Therapeutics, Ltd, grants from NIH-NIAID, grants from Genentech, personal fees from AllerGenis, personal fees from Abbott Nutrition International, grants and personal fees from DBV Technologies, personal fees from Vincido Medical Education, personal fees from WebMD and grants from Astellas.
Justin Skripak, MD
Assistant Professor of Pediatric Allergy and Immunology
Mount Sinai School of Medicine
JS declares that he has no competing interests.
Hugh A. Sampson, MD
Professor of Pediatrics
Mount Sinai School of Medicine
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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