Allergy to food
Symptoms usually begin immediately, within 2 hours after eating. Rarely, the symptoms may begin hours after eating the offending food.
If you develop symptoms shortly after eating a specific food, you may have a food allergy. Key symptoms include
Other symptoms that may occur include:
Abdominal pain Diarrhea Difficulty swallowing
Itchingof the mouth, throat, eyes, skin, or any area
- Lightheadedness or
fainting Nasal congestion Nausea Runny nose
- Patches of itchy, scaly skin (atopic dermatitis); skin may peel or blister
- Swelling (
angioedema), especially of the eyelids, face, lips, and tongue Shortness of breath Stomach cramps Vomiting
Symptoms of mouth (oral) allergy syndrome:
- Itchy lips, tongue, and throat
- Swollen lips (sometimes)
Signs and tests
In severe reactions, you may have
Blood or skin tests are sometimes used to confirm that you have an allergy. However, there is no well-accepted criteria for diagnosing food allergies.
With elimination diets, you avoid the suspected food until your symptoms disappear. Then the foods are reintroduced to see if you develop an allergic reaction.
In provocation (challenge) testing, you eat a small amount of the suspected food allergen under medical supervision. This type of test may provoke severe allergic reactions. Challenge testing should only be done by a doctor.
Never try to deliberately cause a reaction or reintroduce a food on your own. These tests should only be performed under the guidance of a health care provider -- especially if your first reaction was severe.
Review Date: 06/29/2010
Reviewed By: Paula J. Busse, MD, Assistant Professor of Medicine, Division of Clinical Immunology, Mount Sinai School of Medicine, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.