Food allergies: to test or not to test

(HealthDay)—About 5 percent of American children and 4 percent of adults have a food allergy, but many more are getting unnecessary testing.

Specific blood and skin prick tests can help detect food allergies. But the U.S. National Institute of Allergy and Infectious Diseases recommends them only for people who've had immediate allergic reactions, have a certain type of inflammation of the esophagus, or have moderate to severe atopic dermatitis, which appears as a skin rash.

Testing isn't warranted for conditions like hay fever, mild dermatitis and hives that have no apparent cause.

If you suspect a food allergy, keep a log with these details about each food in question:

• How many minutes after eating the food did symptoms start?
• How much of the food did you eat before symptoms started?
• Have you eaten this food before and had a reaction?
• Do you always have a reaction with certain foods?
• Does taking allergy medication, like an antihistamine, relieve symptoms?

Know the most common food allergens:

• Eggs.
• Milk.
• Peanuts.
• Tree nuts.
• Wheat.
• Shellfish.
• Fish.
• Soy.

Keep in mind that the only way to conclusively diagnose a food allergy is with an oral food challenge, a test that can put you at risk for a severe allergic reaction. So it must be done by an experienced health care professional.

Misdiagnosed allergies can lead to nutritional deficiencies, anxiety and high medical expenses. So talk to your doctor about other options, like keeping a food log, before you start the testing process.

When researchers evaluated people getting tested at one clinic, only one-third had a medical history that suggested food allergy testing was warranted, yet nearly half were already avoiding certain foods. When patients were looked at more closely, nearly 90 percent of those avoiding foods were able to put at least one of them back in their diet.

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