A food allergy is an exaggerated response of the immune system to certain foods, such as milk,
eggs, peanuts, tree nuts, shellfish, fish, wheat, and soy.
An allergy is not the same as food intolerance. Food intolerance can occur with some of the same
foods that cause allergies. Symptoms of food allergy include hives or eczema; hoarse voice;
wheezing; swelling of lips or face; abdominal pain; diarrhea or vomiting; problems swallowing;
difficulty breathing; and itchy eyes, throat, or skin.
Food intolerance often causes abdominal pain or cramps or diarrhea. This can be caused by
cow’s-milk products (lactose intolerance) and grains containing gluten, such as wheat, barley,
and rye (celiac disease).
It is important to accurately identify the suspected food. A health care professional may do this
Providing a small amount of the food under medical supervision (provocation or challenge
Eliminating the food until you are better, then carefully start the food again under medical
supervision (elimination diet)
Using blood or skin tests
These tests should always be done under medical supervision, especially if your first reaction
was severe. Severe cases of food allergy may cause low blood pressure or a blocked (obstructed)
The most important intervention is to avoid the food, which may require careful reading of labels
and detailed questions when eating out. You may be able to treat mild reactions with antihistamines.
If the reaction is severe, it may cause life-threatening airway obstruction requiring immediate
treatment with epinephrine (adrenaline). If you know you have a food allergy, you should talk to
your doctor about whether you need to carry injectable epinephrine with you at all times.
Allergy shots do not help with food allergies. Sometimes children can outgrow food allergies,
especially allergies to milk, eggs, wheat, and soy. Peanut, tree nut, and shellfish allergies are
more likely to persist throughout life.
National Library of Medicinewww.ncbi.nlm.nih.gov/pubmedhealth/PMH0001820
American Academy of Allergy, Asthma, and Immunologywww.aaaai.org/conditions-and-treatments/library/at-a-glance/food-allergy.aspx
National Institute of Allergy and Infectious Diseaseswww.niaid.nih.gov/topics/foodAllergy/understanding/Pages/default.aspx
To find this and previous JAMA Patient Pages, go to the Patient Page link on
JAMA’s website at jama.com. Many are published in English and Spanish.
Sources: National Institute of Allergy and Infectious Diseases, US Food and Drug
AdministrationChafen JJS, Newberry SJ, Riedl MA, et al. JAMA.
Goodman DM. Food Allergies. JAMA. 2013;310(4):444. doi:10.1001/jama.2013.6853