Allergy to food
Symptoms usually begin immediately, within 2 hours after eating. Rarely, the symptoms may begin hours after eating the offending food.
Other symptoms that may occur include:
Symptoms of mouth (oral) allergy syndrome:
In severe reactions, you may have low blood pressure and blocked airways.
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.
See: Allergy testing
Lack G. Clinical practice. Food allergy. N Engl J Med. 2008;359:1252-1260.
Chafen JJ, Newberry SJ, Riedl MA, et al. Diagnosing and managing common food allergies: a systematic review. JAMA. 2010 May 12;303(18):1848-56.
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