Health

Food Allergy Update

By the editors of Your Family Today

Food allergies are a very common concern among parents -- and with good reason. The number of kids with food allergies has risen 18 percent in just 10 years, according to a 2009 study by the U.S. Centers for Disease Control and Prevention. Parents of nearly 4 percent of American children reported that their child is allergic to at least one food, the study showed, and the number of hospital visits due to food allergies in children has tripled.

Even though the rise in allergies is very real, parents often blame food for mild symptoms that are actually caused by something else. To avoid a misdiagnosis by Dr. Mom (or Dr. Dad), here are common symptoms of exposure to nonfood allergens, plus a quick guide to the three methods of testing for true food allergies.

Symptoms of Nonfood Allergies
Before modifying your child’s diet and forbidding any favorite -- or perhaps not-so-favorite -- foods, note that these common symptoms may be caused by nonfood allergens:

• Rashes and hives can result from viral infections, harsh soaps and topical irritants.
• Nasal congestion, cough or wheezing can result from a virus or contact with airborne allergens, such as ragweed and pollen.
• Abdominal pain, nausea and diarrhea can be caused by an intolerance of milk products (lactose intolerance) but may actually be symptomatic of a gastrointestinal virus that makes it hard to digest certain foods, such as milk.

Testing for True Food Allergies
If you still suspect your child is allergic to food, consult your pediatrician, who can rule out other sources. Then, your child will need to undergo allergy testing to accurately identify the food (if any) responsible for the reactions. According to Dr. Michael G. Marcus, director of pulmonology, allergy and immunology at Maimonides Medical Center, in Brooklyn, N.Y., three different types of tests are available:

1. Skin tests have been used for more than 80 years to pinpoint allergy triggers, and they are between 80 to 95 percent accurate. These tests involve introducing a minute amount of purified food extract under the skin with a small needle and observing the reaction after 20 minutes.

2. Blood tests (aka radioallergosorbent tests, or RAST) are an alternative to skin testing. The advantage of RAST is that it requires only one to two vials of blood through one needlestick rather than the 20 or more scratches like in skin testing. The disadvantage: It’s only 80 percent accurate, at best.

3. Double-blind food challenge is the "gold standard" for testing, and it requires that patients consume a capsule containing a small quantity of concentrated food -- without knowing what the food is. If patients develop the same reaction after two to three challenges with the same food, then it is considered a true positive reaction. Once the offending food is identified, the only acceptable treatment is total avoidance. No other treatment will effectively prevent reactions. Antihistamines can relieve symptoms, but as they wear off, the symptoms may return. After avoiding the food for anywhere from six months to more than two years, a child will likely be able to tolerate it when it's repeatedly reintroduced.

Food allergies are usually mild, but they can be very serious. In rare cases, severe allergic reactions may lead to shock or death. If your child experiences tingling sensations, dizziness, generalized itching and hives, wheezing and difficulty breathing, or fainting, seek immediate medical attention.

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