Food Allergies

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There currently is no cure for food allergy, so the best way to prevent symptoms is to avoid the foods to which you are allergic by going on an appropriate elimination diet. However, even with careful attention to detail, accidental exposure to offending foods occurs all too often. As a result, a plan for treating allergic reactions should be developed with your doctor (or your child's doctor), written down, and carried along with the medications needed for treating a severe allergic reaction. These medications include a self-injectable epinephrine device along with a rapidly absorbable form of an antihistamine. New treatments for Food Allergies are being actively sought, and several approaches currently under investigation appear promising. This section contains information on:

  • Elimination diet
  • Medications
  • Elimination diet

    Once the foods capable of causing an allergic reaction in a person have been accurately identified, an elimination diet should be constructed that reliably excludes all of them. When the diet is quite restricted, its nutritional adequacy should be reviewed with a doctor or a dietitian. For example, care should be taken that children on a dairy-free diet consume adequate amounts of calcium and vitamin D. The different terms used to refer to the incriminated foods on a label—and how to accurately read labels—should be reviewed as well. It's also important to discuss common sources of accidental exposure: the foods in which the allergen might be found as a hidden ingredient.

    Medications

    People with Food Allergies are encouraged to always carry the medications needed to treat an allergic reaction caused by an accidental exposure to an offending food. They are rarely placed on daily medications; once the allergy has been correctly diagnosed, they should not have symptoms as long as they adhere to an elimination diet. People with asthma who have Food Allergies should take the medications prescribed to keep the asthma under good control. They are at higher risk for severe allergic reactions to foods, particularly when the asthma is poorly controlled.

    This section contains more on some of the more common medications used for food allergy:

    • Antihistamines
    • Steroids
    • Epinephrine for anaphylaxis
    • It also contains information on other potential therapies.

      Antihistamines

      Antihistamines are used to treat a variety of allergic disorders. They work by blocking the actions of a chemical called histamine, which is released by special cells of the body's immune system and triggers a number of the symptoms associated with allergic reactions. There are many different antihistamines available both over the counter and by prescription. They are often given as needed to treat the symptoms resulting from an allergic reaction to a food. You should discuss with your doctor which antihistamine to use (and the appropriate dose) if you or your child has an allergic reaction. It should be remembered that antihistamines start working relatively slowly and that the first drug of choice for treating significant or progressing reactions is injected epinephrine.

      Steroids

      Steroids are potent anti-inflammatory medicines that are often used to treat allergic disease. For people with Food Allergies, steroids are occasionally prescribed either in a liquid or tablet form for short periods to decrease the inflammation that may accompany a significant reaction.

      Epinephrine for anaphylaxis

      People with severe allergies can have life-threatening allergic reactions involving more than one organ system (lungs, skin, gastrointestinal tract, cardiovascular system) called anaphylaxis. If someone has symptoms of anaphylaxis, he or she needs emergency medical attention. If the person has an injectable epinephrine device, epinephrine should be given right away, and 911 should then be called to transport the person to an emergency medical facility.

      Epinephrine is the most important medication for the treatment of anaphylaxis. It works best when injected into a muscle on the outer thigh. Once absorbed into the bloodstream, epinephrine works rapidly to contract blood vessels, preventing them from leaking fluid. It also relaxes airways, relieves cramping in the gastrointestinal tract, decreases swelling, and blocks itching and hives.

      Physicians often suggest that individuals who have had allergic reactions to foods carry epinephrine with them at all times. This medication, available only by prescription, is sold under the names EpiPen® or EpiPen Jr.® (for children), Twinject 0.3 mg auto-injector® , or Twinject 0.15 mg auto-injector® (for children). At-risk individuals or any person who might need to administer the injection should be trained in the use of these devices.

      Some medicines given for high blood pressure (called beta blockers) can partially counteract the effects of epinephrine, making the treatment of anaphylaxis more difficult in these people. Allergic individuals with high blood pressure may want to ask their physician about the possibility of switching to a different type of high blood pressure medication.

      Even if the individual responds to epinephrine, it is vitally important to go to an emergency room immediately! The effects of epinephrine may wear off after several minutes, requiring another dose, or other treatments may be needed, such as oxygen and/or medications to improve breathing. Intravenous fluids may be necessary to restore and maintain adequate blood pressure. Additional medications may be given to counteract the effects of histamine and to help prevent a delayed allergic reaction.

      In addition, people at risk for anaphylaxis should consider:

      • Wearing a medical alert bracelet at all times.
      • Seeing a board-certified allergist.
      • Carrying an emergency kit with an antihistamine in addition to the self-injectable epinephrine device. (Make sure to replace the injectable epinephrine device before it reaches its expiration date.) The emergency kit should also contain a written plan outlining the treatment of allergic reactions along with the phone numbers of people to be notified in case of a reaction. If your child has Food Allergies, have an action plan and emergency kit available at each place your child spends time, including school and day-care centers. Make sure to review the action plan with the staff at these places, and be sure that they know when and how to administer epinephrine and any other medication listed on the action plan.
      • Other Potential Therapies

        Anti-IgE

        Anti-IgE is a medication currently approved for the treatment of severe asthma that  might help people with food allergies avoid life-threatening reactions. A study in the New England Journal of Medicine looked at people allergic to peanuts and found that treatment with the medicine raised the average amount of peanut it took to trigger an allergic reaction from approximately one half of a peanut to nearly nine peanuts.

        IgE is an antibody with one end that binds to the surface of a specialized cell called a mast cell and another end that binds to a specific allergen. When IgE bound to a mast cell comes into contact with the appropriate allergen, it triggers an allergic response. The anti-IgE medication tested in the study was a genetically engineered IgE antibody that is administered by injection. It works by binding to IgE at the site where the antibody normally binds to a mast cell, blocking that action and thereby decreasing the likelihood of an allergic reaction. Although it appears unlikely that anti-IgE will be used as a sole treatment of food allergy, it may be used in the future in combination with other treatment approaches.

        Oral Immunotherapy

        Oral immunotherapy (OIT) consists of initially giving very small (milligram) doses of the food allergen by mouth and gradually increasing the amount to a predetermined maintenance dose. The maintenance dose of food allergen is then given daily for months to years in an attempt to cure the food allergy. Initial studies examining oral immunotherapy with peanut, egg or milk suggest that this will be an effective therapy for some food allergic patients. While some patients may be cured with oral immunotherapy, others who are not cured may still benefit from having a higher threshold dose while on treatment. The use of sublingual immunotherapy (SLIT), where a smaller dose of food allergen is given sublingually rather than orally, is also currently under investigation.

        Other Therapies

        Other novel therapies being considered for the treatment of food allergy include immunotherapy using altered food allergens administered with specific substances to boost the immune response and a modified Chinese herbal therapy. Studies on these and other approaches to food allergy treatment suggest that reliable therapies

        Last reviewed on 11/6/09

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