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Ask the Expert: What is the best way to treat a food allergy?

Ejaz Yousef, M.D.
Ejaz Yousef, M.D.​
Pediatrics – Allergy and Immunology
Sees patients at Marshfield Clinic Marshfield Center

​Q: What is the best way to diagnose and treat a food allergy?​

A: It's best to first know what food allergy is. Food allergies occur when your body's immune system identifies certain food proteins as harmful. Your immune system produces antibodies to combat what it perceives to be a foreign substance, which triggers the response.

This allergic reaction can cause inflammation of the gastrointestinal tract, manifested by abdominal pain, diarrhea and vomiting; swelling of the respiratory tract, which can also lead to choking; skin rash and itching; and anaphylaxis, a life-threatening loss of blood pressure.

About 90 percent of all food allergies are caused by a handful of foods, including cow's milk, peanuts, wheat-based foods, fish and shellfish. In a recent research paper I co-published with two other researchers, we found that peanut and milk allergies were also associated with increased hospitalization and steroid use, and may serve as early markers for an increased susceptibility to asthma.

When determining if a reaction to food is actually an allergy, family history is the primary factor we investigate. If a sibling or another close relative has a food allergy, eczema, asthma or rhinitis (irritation and inflammation of the mucous membrane inside the nose), it greatly increases the possibility that a patient has a food allergy.

Potential risk for allergic food reactions is greater at a younger age; such reactions occur in 6 to 8 percent of children under age 5, as opposed to a rate of 1 to 3 percent among adults. 

After getting a history, we conduct a series of tests – a skin test, blood test and, finally, the "gold standard" test, the food challenge. These tests are both open and blinded. If the patient "passes," or doesn't experience a reaction during any of these tests, we can conclude that he or she doesn't have a food allergy. In general, we are successfully able to clear a vast majority of patients who are misdiagnosed as having "food allergy."

For those who do test positive for food allergy, the most logical counsel, of course, is to avoid the suspected foods and carry emergency medications, including EpiPen® (injectable epinephrine), if required. Several promising therapies for food allergy, including food desensitization, are in various stages of development and will be made available to food allergy sufferers in central Wisconsin in the near future.