Allergy Sleuthing: How to Determine Which Food Is the Problem

If you suspect that you or your child has a food allergy, you must track down the culprit. The first step often involves considering some detailed questions.

When you develop symptoms, ask yourself:

• Did the reaction come on within an hour after eating?
• Has this happened before, after eating this food?
• Was my child or I the only person who got sick?
• Was the food properly prepared and cooked?
• Did allergy medicines help clear up hives, a stuffy nose, and other symptoms, if applicable?

If you answered yes to all of these questions, you may have a food allergy. Other possible causes of food reactions are food intolerances and food poisoning.

To help track down the food culprit, write down everything you eat for one or two weeks. Record what symptoms you have and how long after eating they show up. Share this with your doctor. This, plus tests, can help your doctor find the cause of your problem.

Your doctor also may put you on an elimination diet to see if you have a food allergy. In this kind of diet, you avoid the food, and if symptoms go away, you probably have a food allergy. If you eat the food under your doctor's supervision and the symptoms come back, then the food allergy is confirmed. However, people with severe reactions cannot try an elimination diet because it is too dangerous.

Another way to find the cause of your problem is through allergy testing. A common method is the scratch skin test. An allergist places a food sample on the skin and scratches the skin with a needle. If the skin becomes red or swollen, you probably have an allergy.

Blood tests and other methods also may be used to determine if you have a food allergy.