Emergency: requires immediate attention
Food allergy
Alerts and Notices
Synopsis

Hypersensitivities classically develop through primary sensitization, with either gastrointestinal (GI) or cutaneous exposure resulting in the development of an immune response to an allergen. Some of these allergies may occur through secondary sensitization, or allergen cross-reactivity. For example, someone who develops a hypersensitivity to dust mite or cockroach proteins may later develop shellfish allergies.
There are 5 main presentations of food hypersensitivity disorders in adults:
- Immunoglobulin E (IgE)-mediated anaphylaxis (most common)
- Food-dependent, exercise-induced anaphylaxis
- Oral allergy syndrome
- Delayed anaphylaxis to mammalian meats (see alpha-gal syndrome)
- Food protein-induced enterocolitis syndrome
Codes
ICD10CM:Z91.010 – Allergy to peanuts
Z91.011 – Allergy to milk products
Z91.018 – Allergy to other foods
SNOMEDCT:
414285001 – Allergy to food
Look For
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
- Other allergies – bee stings and other insect stings, latex, medications
- Food intolerances – lactase deficiency, alcohol dehydrogenase deficiency
- Migraine headaches – some foods can be triggers for migraines, including chocolates, cheeses, caffeine, alcohol, soy, preservatives, and more
- Scombroid poisoning – foodborne illness from spoiled fish that is high in histamine
- Food poisoning – commonly caused by Staphylococcus aureus, Escherichia coli, Salmonella, Shigella, Bacillus cereus, Campylobacter, and Listeria; symptoms are usually more delayed
- Celiac disease – immune-mediated gluten intolerance
- Inflammatory bowel disease (see Crohn disease, ulcerative colitis) – immune-mediated disorders resulting in chronic inflammation and GI symptoms
- Irritable bowel syndrome – GI symptoms may be exacerbated by certain foods
- Hereditary angioedema
- Acute respiratory decompensation from severe asthma, foreign body aspiration, or pulmonary embolism
- Carcinoid syndrome
- Pheochromocytoma
- Panic attack
Best Tests
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Management Pearls
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Therapy
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References
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Last Reviewed:07/01/2020
Last Updated:07/26/2020
Last Updated:07/26/2020