Johanna Lynch of Wilton, NewHampshire, worries she looks like a“lunatic” to others when she wipesoff tables and chairs in restaurantsand insists that family and friendskeep more than 60 foods out ofreach of her 2-year-old son, Emmett.

Her behavior is not a form of mad-ness; it is a common response to anever-present threat. Allergy tests andexperience confirm that Emmettcould have a life-threatening reactionto even a minuscule amount of anyfood to which he is allergic. Lynch ispart of a rapidly growing group ofworried parents. The Asthma &Allergy Foundation of America reportsthat 6% to 8% of all school-age chil-dren have at least one food allergy.

Emmett was just 2 weeks oldwhen Johanna noticed he had trou-ble breathing 10 to 15 minutes afterbeing fed a milk-based infant formu-la. Johanna quickly began feedinghim a hypoallergenic diet. A bloodtest known as the IgE RAST(Immunoglobulin E, radioallergosor-bent test), performed at 6 and 9months of age, confirmed that manyof Emmett’s health problems weredue to food allergies. Shortly afterEmmett’s first birthday, an allergistperformed skin prick tests, revealingthe toddler’s allergies to milk, eggs,soy, sesame, peanuts, strawberries,and raspberries. Lynch says Emmettlater developed allergies to cranber-ries, mustard, and cat dander as well.His allergies have had a profoundeffect on his family’s daily routines.

“Children shouldn’t be exposed toanything that makes them sick, nomatter what it is,” says Lynch. “Ourfamily has eliminated almost all pre-pared food from our diets. I havebecome very strict about what foodsare brought into the house.” Sheadds that she is now an avid foodlabel reader. “It affects every part ofour family life. It’s on our minds allthe time.”

Despite his allergies, Emmett,who recently suffered his first asthmaattack, is a typical toddler in mostrespects. “He eats everything that

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isn’t nailed down” and his height andweight are above average. Lynchadvises other parents facing similarsituations to learn all they can aboutfood allergies, join a support group,and see the appropriate medical spe-cialists.

Michael Young, MD, a board-certified allergist who authored ThePeanut Allergy Answer Book, agreeswith Lynch’s suggestions. He explainsthat the most common symptoms offood allergies are flushing of the skin,hives, swelling of the lips or eyelids,eczema, nausea, vomiting, and diar-rhea. Less common symptomsinclude breathing difficulty, throattightness, wheezing, and asthma. Insevere cases, food allergies can causeanaphylaxis, a potentially fatal sys-temic allergic reaction. Anaphylaxissymptoms may include a tinglingsensation in the mouth, swelling ofthe throat, difficulty breathing, hives,vomiting, abdominal cramps, diar-rhea, drop in blood pressure, andloss of consciousness.

Most allergic reactions are less dra-matic but should prompt parents toinvestigate the source. “The first stepfor parents who suspect their childhas a food allergy should be to try to

correlate the allergic symptoms with aparticular food or foods. Once theseare identified, the best treatment isavoidance,” says Dr. Young. Seek thehelp of an allergist/immunologist toidentify the offending foods; there aresimple allergy tests that can beadministered to accomplish this.

What to Expect WithAllergy Testing

There are 3 widely accepted med-ical methods of diagnosing foodallergies. Most allergy tests are safe atany age, even during infancy. Dr.Young says it is not unusual to per-form more than one type of testbefore making a specific diagnosis.The 2 most frequently used means ofevaluating for allergies are skin-pricktests and IgE RAST blood tests.These may then be followed by afood challenge test to confirm orclarify findings.

Skin-Prick TestsTo perform a skin test, a drop of

the suspected allergen is placed onthe forearm or back. The skin is thenpricked with a tiny needle so that asmall amount of the substance entersthe skin. Redness or swelling similar

to a mosquito bite is evidence of anallergic reaction. The test is notpainful and results are almost imme-diate, which are reasons for its popu-larity. However, false positive resultsmake skin testing less than 100%reliable.

“Skin-prick testing is very inex-pensive and takes just seconds,” saysStanley Goldstein, MD, director ofAllergy and Asthma Care of LongIsland and Island Medical Researchin Rockville Centre, New York. “Italso provides a great educationopportunity. When parents see apositive skin test it tells themmuch more than hearing about theresults of a blood test a couple ofdays after it’s performed. However,there are specific instances when Iask for blood tests, such as when achild has severe eczema, is takingan antihistamine, or when there isconcern about an anaphylacticreaction.”

Blood TestsIgE RAST blood tests evaluate for

the presence of food allergies and canprovide some information on theseverity of the allergy. After blood isdrawn from the patient, it is sent to

American Academy of Allergy, Asthma& Immunology611 East Wells StreetMilwaukee, WI 53202Phone: (414) 272-6071Website: www.aaaai.org

American College of Allergy, Asthma &Immunology85 West Algonquin Road, Suite 550Arlington Heights, IL 60005Phone: (800) 842-7777Website: http://allergy.mcg.edu/home.html

The Food Allergy & Anaphylaxis Network11781 Lee Jackson Hwy., Suite 160Fairfax, VA 22033-3309Phone: (800) 929-4040Website: www.foodallergy.org

More information about foodallergies is available from the

following sources.

A blood test known as IgE RASTtests for the presence ofspecific allergies.

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a laboratory for testing. The labora-tory measures the level of antibodiesproduced after blood is exposed to aspecific substance. Dr. Goldsteincautions, however, that a positive testresult does not always mean a reac-tion will actually occur when thepatient is exposed to the particularfood.

A new method of RAST testing,known as the CAP-RAST FEIA test,can be useful in determining allergiesto certain foods. This test may alsoprove to be an effective way to followlevels of particular IgE antibodiesover time to determine whether achild is outgrowing an allergy.

Food ChallengeOccasionally, a diagnosis is still in

doubt after skin and blood testing.When the allergy is potentially lifethreatening, a food challenge is oftenrecommended. The challenge shouldbe done by a board-certified allergistand must take place in the doctor’soffice or a hospital setting whereemergency care is available if needed.(Sometimes the challenge may bedouble blind, which means neitherthe physician nor the patient knowswhether the food being given is thesuspected allergen or a harmless sub-stance.) Increasing amounts of thesuspected allergen or placebo aregiven as the challenge progresses.The physician continuously looks forsigns of an allergic reaction.

Although this is the gold standardfor pinpointing food allergies, it hasrisks. It is typically done only afterother types of testing have consis-tently revealed no allergic response tothe food to be tested.

Dr. Goldstein recommends start-ing simple. “I take the easiest stepsfirst, which is why I prefer to beginwith skin testing, especially withyoung children,” he explains. “I tryto use the least invasive methodswhen testing children. Having theirblood drawn with a needle for ablood test is scarier for most childrenthan a skin-prick allergy test.”

Food Allergies Can BeWell Managed

For now, there is no treatment toprevent food allergies, only medica-tions to treat symptoms. Severalstudies have suggested that breast-feeding in infancy can reduce theincidence of allergies and asthma inchildren. It is also thought that chil-dren at high risk for food allergy (ie,food allergy, asthma, or eczema runsin the family) should not be exposedto known allergenic foods, such aspeanuts or nuts, for the first fewyears of life. Avoidance, education,and prevention are the keys to pre-venting food allergies from striking.

Once a food allergy is identified,it is important to learn as much aspossible about avoidance and treat-ment measures. Johanna Lynch is

already wondering whether she willfeel secure about sending her sonEmmett off to school or to playtimeat other children’s homes when he isolder. She is investigating the policiesof local schools and seeking guidancefrom parents who have experiencewith those situations. With the prop-er education and vigilance, foodallergies can be well managed, andthose who are affected can live fulllives with few restraints on theiractivities.

Gregory Alford is a freelance writer inIllinois.

Reprint orders: Elsevier Inc., 11830 WestlineIndustrial Dr., St. Louis, MO 63146-3318;phone (314) 453-4350.doi 10.1016/j.asthmamag.2003.11.00

Up to 2 million children in the UnitedStates are affected by food allergy.

With a true food allergy, an individual’simmune system overreacts to an ordinarilyharmless food. Food intolerance is some-times confused with food allergy. Food intol-erance refers to an abnormal response to afood or food additive that is not an allergicreaction. It differs from an allergy in that itdoes not involve the immune system.

Food allergens—those parts of foods thatcause allergic reactions—are usually pro-teins. Most of these allergens can stillcause reactions even after they are cookedor have undergone digestion in theintestines. Numerous food proteins havebeen studied to establish allergen content.

The most common food allergens, whichare responsible for up to 90% of all allergicreactions, are the proteins in cow’s milk,eggs, peanuts, wheat, soy, fish, shellfish,and tree nuts.

In some food groups, especially tree nutsand seafood, an allergy to one member of afood family may result in the person beingallergic to other members of the samegroup. This is known as cross-reactivity.

Source: American Academy of Allergy,Asthma & Immunology

Food Allergy Facts

A skin-test is quick, causes little pain, and provides fairlyaccurate results.