Eosinophilic Gastrointestinal Disease Program
Allergy tests
Identification of foods that may be triggering your child’s condition may be performed by any of the following methods described below.
No test can definitively diagnose or rule out an allergy. All results need to be interpreted by an allergist in context of the medical history.
Skin prick tests
- used to evaluate for food and environmental allergies
- performed by applying a drop of suspected allergen on to the surface of the skin
- a positive test will be seen within 15 to 20 minutes with a hive and redness at the test site
- a positive test does not always mean your child is allergic to that allergen
- not considered painful but positive reactions can cause itching which may be uncomfortable
- some medications may interfere with skin testing and should not be taken prior to the allergy visit
Blood tests
- commonly known as RAST tests
- used to measure IgE antibodies to food and/or environmental allergens
- may be used when skin tests cannot be performed
- a positive test does not always mean your child is allergic to that allergen
- does not predict the severity or the type of reaction, but gives information on the likelihood of having a reaction if exposed to a particular allergen
Food patch tests
- used to detect possible delayed-type food allergies
- differs from the RAST blood test or skin prick tests, which are used to evaluate for immediate (IgE-mediated) reactions that may result in symptoms such as hives or anaphylaxis.
- requires two separate visits to the Allergy Program
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during the initial visit, a food patch test panel will be placed on the back of you/your child. These panels consist of prepared foods placed on shallow aluminum disks that are secured to your child’s back with tape. The selection of foods to be tested will be determined by your allergist.
