If you suspect you have a food allergy, your allergist will typically recommend one of several types of tests to determine if you are allergic to a specific food, such as wheat, soy, milk, nuts, fish or shellfish.
Most people will undergo an allergy skin test. During this test, a small drop of purified food extract is placed on the skin to see if your skin has a reaction. If you have over-reactive skin or eczema, skin testing may produce a false positive reaction, in which case you may need a blood test.
Depending on the test results, further testing may be needed, including:
- An elimination diet that cuts the suspected food out of your diet to see if there is a change in your symptoms.
- An in-office food allergy challenge. Common foods that are used in a food challenge include cow milk, eggs, wheat, peanuts, nuts and shellfish.
You will be asked to bring in the specific food for the challenge. During the food allergy challenge, the food is given in increasing amounts every 20 minutes. After the last dose, a longer observation period is required to ensure there is not a late reaction. If a late reaction occurs, you may be required to remain in the office until the reaction resolves.