Exams and Tests

To diagnose a food allergy, your doctor will start with a medical history and a physical exam. Your doctor may ask:

• What symptoms you have.
• If your family has any food allergies.
• How soon the symptoms begin after eating food.
• If over-the-counter medicines helped.
• If other people also got sick.
• How the food was prepared.
• If you ate any other foods.

It's important to find out whether you have a food allergy or food intolerance. Your doctor may ask you to keep a record of all the foods you eat and any reactions you have to them. Your doctor will also consider if your reaction could have been caused by things like allergies to medicines or insect stings, food poisoning, irritants in foods, or exposure to skin irritants.

Your doctor may ask you to try an elimination diet, an oral food allergy challenge, or both.

• In an elimination diet, you avoid eating foods that may be causing an allergic reaction and see if your symptoms go away. If symptoms come back when you eat the food again, your doctor can confirm your food allergy. The elimination diet can last from 2 to 8 weeks.
• In an oral food allergy challenge, you eat a variety of foods that may or may not cause an allergic reaction. Your doctor watches to see if and when a reaction occurs. This test is considered the best way to diagnose a food allergy.

After you have been diagnosed with a food allergy, you may also have allergy tests, such as skin tests or blood tests, to find out which foods you are allergic to.