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Overview |
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Definition |
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A food allergy occurs when the body's immune system responds to otherwise
benign proteins (allergens) as though they threatened the health and integrity
of the system. In a classic reaction, the immune system attempts to counter the
food allergens by stimulating IgE antibodies. When these antibodies react with
the allergen, histamine and other chemicals (mediators) are released. This
process then gives rise to such allergic symptoms as itching, swelling, hives,
and breathing difficulties. While most food allergies are mild, in some cases,
they can cause anaphylactic shock. Because this type of reaction can be
life-threatening, food allergies must be taken seriously.
Approximately 5% of children younger than age 3 have food allergies. As many
as two out of five Americans believe that they have allergies to certain foods.
According to the National Institute of Allergy and Infectious diseases, fewer
than 2%—about 4 million
Americans—have true food allergies.
The majority of adverse reactions to food are caused by nonimmunologic
mediated mechanisms. Also called food intolerance or food hypersensitivity,
adverse food reactions can occur because a person lacks the enzymes needed for
proper digestion, such as for the lactose in milk, or has a sensitivity to such
common preservatives and additives as monosodium glutamate (MSG), sulfites, and
gluten. Some adverse reactions are caused by food-borne microbial pathogens and
toxins. |
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Etiology |
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Foods that most commonly cause allergic reactions include peanuts, tree nuts,
milk, eggs, soy, fish, shellfish, wheat, some fruits, seeds, and chocolate. Food
allergies arise when a genetic sensitivity is coupled with environmental
exposure. |
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Risk Factors |
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- Family history of allergies, asthma, or atopic dermatitis
- Personal history of asthma, atopic dermatitis, or other
allergies
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Signs and Symptoms |
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- Patches of swelling (urticaria, angioedema), atopic dermatitis,
hives
- Swelling or itching lips, tongue, and mouth
- Itching or tightness in the throat
- Runny and itchy nose
- Headache
- Nausea, cramping, vomiting, flatulence, diarrhea
- Respiratory distress
The following symptoms should be treated as a medical
emergency.
- Immediate and extreme facial swelling and itching
- Breathing difficulties
- Rapid increase in heart rate
- Rapid drop in blood pressure
- Tightening of the throat
- Sudden hoarseness
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Differential
Diagnosis |
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- Food intolerance or food poisoning
- Seasonal or environmental allergies or asthma
- Mononucleosis
- Viral hepatitis
- Parasitic infection
- Urticarial vasculitis
- Skin malignancy
- Connective tissue disease
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Diagnosis |
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Physical Examination |
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Physical assessment includes noting characteristic symptoms, signs, and
pattern of reaction, as well as a history of past exposures and reactions to
related foods. |
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Laboratory Tests |
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The blood tests radioallergosorbent (RAST) and enzyme-linked immunosorbent
assay (ELISA) are generally more useful in ruling out a food allergy than
diagnosing one. |
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Pathology/Pathophysiology |
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Blood tests reveal elevated levels of IgE antibodies or the presence of
eosinophilia. |
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Imaging |
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In rare cases of gastric inflammation, an upper GI series may be
needed. |
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Other Diagnostic
Procedures |
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Assess the likelihood of a more serious reaction through the examination,
patient's history, and description of reaction pattern to certain foods. Further
tests may be needed to assess patient's overall susceptibility to food and other
allergies. Suggest that patient keep a food diary that tracks eating habits,
medications, and adverse reactions.
- Elimination trial, supervised by health care provider. See
"Nutrition" section.
- Skin tests that measure a person's reactions to superficial contact
with suspected allergens can determine or rule out a food allergy.
- Challenge or provocative testing involves placing food extracts under
the tongue or injecting them under the skin. However, this test tends to be
expensive and unreliable. Provoking symptoms is not advised for patients who
have experienced anaphylactic reactions to foods, insect stings, or
medications.
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Treatment Options |
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Treatment Strategy |
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There is no cure for food allergies. Managing them usually means avoiding
offending foods and treating symptoms when they occur. If the problem involves
food intolerance, a registered dietitian may be helpful in guiding the patient
so that reactions are minimized, thus avoiding unnecessary food
restrictions.
Usually, once the food is eliminated from the diet, symptoms will abate.
However, avoidance may not always be possible. For example, the substance may be
present as an unspecified additive within another food or "hidden" in another
form. Other factors such as the amount of the food, which parts of the food are
used, or the way in which it is prepared can influence the systemic response.
Therefore, treatment may be necessary to address occasional allergic
symptoms. |
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Drug Therapies |
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- Antihistamines—for mild itching, swelling,
rash, runny nose, or headache; available both by prescription and over the
counter in many cold, sinus, and allergy remedies. These include diphenhydramine
(Benadryl), clemastine (Tavist), chlorpheniramine (Chlor-Trimeton), loratadine
(Claritin), and astemizole (Hismanal). Possible side effects include drowsiness,
irritability, dry mouth, and heart palpitations. Hismanal when used with
erythromycin, clarithromycin, and antifungal medications such as Nizoral and
Sporanox can cause irregular heartbeat, fainting, dizziness, and, rarely,
cardiac arrest and death.
- Antispasmodics—such as hyoscyamine (Levsin,
Anaspaz) for diarrhea, nausea, abdominal bloating, and cramping.
- Adrenaline (epinephrine injection)—for
anaphylactic shock.
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Complementary and Alternative
Therapies |
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The key to treatment of food allergy is complete avoidance of allergens for
four to six months. Reducing inflammation, minimizing hypersensitivity
reactions, and restoring the integrity of the digestive tract are ways in which
alternative therapies may help resolve food allergies.
Hypersensitivity reactions may be associated with stress and anxiety.
Mind-body techniques such as meditation, tai chi, yoga, and stress management
may help normalize immune function. |
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Nutrition |
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Note: Lower doses are for children.
- Eliminate all food allergens from the diet. The most common
allergenic foods are dairy, soy, citrus, peanuts, wheat, fish, eggs, corn,
chocolate, and tomatoes.
- An elimination/challenge trial may be helpful in uncovering
sensitivities. Remove suspected allergens from the diet for two weeks.
Re-introduce foods at the rate of one food every three days. Watch for reactions
which may include gastrointestinal upset, mood changes, headaches, and
exacerbation of symptoms. Do not perform a challenge with peanuts if there is
history of anaphylaxis.
- A rotation diet, in which the same food is not eaten more than once
every four days, may be helpful in minimizing food allergies.
- Reduce pro-inflammatory foods in the diet including saturated fats
(meats, especially poultry, and dairy), refined foods, and sugar. For those with
sensitivities to antibiotics it is essential to eat only organic meats to avoid
antibiotic residues.
- Increase intake of fresh vegetables, whole grains, and essential
fatty acids (cold-water fish, nuts, and seeds).
- Flaxseed, borage, or evening primrose oil (1,000 to 1,500 mg one to
two times/day) are anti-inflammatory. Children should be supplemented with cod
liver oil (½ to 1 tsp./day).
- Zinc (10 to 30 mg/day) and beta-carotene (25,000 to 50,000 IU/day)
support immune function and encourage healing of mucosal tissues.
- Vitamin C (250 to 1,000 mg bid to qid) inhibits histamine release.
Vitamin C from rose hips or palmitate is citrus-free and
hypoallergenic.
- B-complex vitamins (25 to 100 mg/day) help to reduce the effects of
stress and normalize immune function.
- Selenium (50 to 200 mcg/day) helps to regulate fatty acid metabolism
and is a cofactor in liver detoxification.
- Bromelain (100 to 250 mg between meals) is a proteolytic enzyme that
decreases inflammation.
- Pancreatin (8X USP) one to two tablets with meals to enhance
digestion.
- Pro-flora supplements (one to three capsules/day) can help to
normalize bowel flora.
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Herbs |
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Herbs are generally a safe way to strengthen and tone the body's systems. As
with any therapy, it is important to ascertain a diagnosis before pursuing
treatment. Herbs may be used as dried extracts (capsules, powders, teas),
glycerites (glycerine extracts), or tinctures (alcohol extracts). Unless
otherwise indicated, teas should be made with 1 tsp. herb per cup of hot water.
Steep covered 5 to 10 minutes for leaf or flowers, and 10 to 20 minutes for
roots. Drink 2 to 4 cups/day. Tinctures may be used singly or in combination as
noted.
- Quercetin (100 to 250 mg tid before meals) minimizes reactions to
food.
- Rose hips (Rosa canina) tea is anti-inflammatory, high in
hypoallergenic vitamin C, and healing to the digestive tract. Drink 3 to 4
cups/day, 4 oz. tid to qid for children. This is particularly effective for
children.
- Marshmallow root tea (Althea officinalis) may soothe and
promote healing of gastrointestinal inflammation. Soak 1 heaping tbsp. of
marshmallow root in 1 qt. of cold water overnight. Strain and drink throughout
the day.
- Dandelion (Taraxacum officinale), milk thistle (Silybum
marianum), celandine (Chelidonium majus), and chicory (Cichorium
intybus) stimulate liver function.
- Soothing carminative herbs will enhance digestion and reduce spasm.
Choose three or more of the following to make a tea to sip before meals.
Chamomile (Matricaria recutita), peppermint (Mentha piperita),
passionflower (Passiflora incarnata), meadowsweet (Filipendula
ulmaria), fennel (Foeniculum vulgare), and catnip (Nepeta
cataria).
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Homeopathy |
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An experienced homeopath should assess individual constitutional types and
severity of disease to select the correct remedy and
potency. |
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Acupuncture |
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Acupuncture may help restore normal immune function and reduce the
hypersensitivity response. |
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Massage |
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Therapeutic massage may help reduce the effects of
stress. |
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Patient Monitoring |
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A diet based on vegetables, fruits, and high-fiber foods and one that is also
low in fat and refined sugar is considered best when addressing any type of
allergy. Because there seems to be a connection between the inflammatory process
and animal fat, it may help to reduce consumption of animal
products. |
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Other
Considerations |
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Prevention |
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Conservative introduction of solid foods as child is weaning may help prevent
hypersensitivity conditions. If there is a strong family history of allergies or
atopic conditions and/or if the child's immunity has been compromised in
infancy, delay the introduction of highly allergenic foods until one year or
older. |
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Complications/Sequelae |
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Some research suggests a link between food allergies and celiac disease,
arthritis, chronic infection, depression, anxiety, and chronic
fatigue. |
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Prognosis |
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Most infants outgrow their sensitivity to food by 2 to 4 years. Adults with
food allergies tend to retain them for years. While there is no cure for food
allergies, prognosis for remaining symptom-free is excellent as long as
offending foods are identified and avoided. |
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Pregnancy |
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Nutritional support may safely relieve symptoms during
pregnancy. |
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References |
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American College of Allergy, Asthma and Immunology. Accessed at
www.allergy.mcg.edu on January 1, 1999.
Carey CF, Lee HH, Woeltje KF, eds. The Washington Manual of Medical
Therapeutics. 29th ed. New York, NY: Lippincott-Raven; 1998:216-217,
223-225.
Dambro MD, ed. Griffith's 5 Minute Clinical Consult. Baltimore, Md:
Williams & Wilkins; 1998:400-401.
Fauci AS, Braunwald E, Isselbacher KJ, et al., eds. Harrison's Principles
of Internal Medicine. 14th ed. St. Louis, Mo: McGraw-Hill; 1997.
The Food Allergy Network. Accessed at www.foodallergy.org/ on January 1,
1999.
Klag MJ, ed. Johns Hopkins Family Health Book. Harper Resource;
1998.
Murray MT. Encyclopedia of Nutritional Supplements. Rocklin, Calif:
Prima Health;1996:448-449.
Murray MT, Pizzorno JE. Encyclopedia of Natural Medicine. 2nd ed.
Rocklin, Calif: Prima Publishing; 1998:321, 464-475.
National Institute of Allergy and Infectious Diseases. National Institute of
Health. Accessed at www.niaid.nih.gov/ on January 1, 1999.
Sampson HA. Food allergy. JAMA. 1997; 278:1888-1894.
Werbach M. Nutritional Influences on Illness. New Canaan, Conn: Keats
Publishing Inc; 1987:23-28. |
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Copyright © 2000 Integrative Medicine
Communications This publication contains
information relating to general principles
of medical care that should not in any event be construed as specific
instructions for individual patients. The publisher does not accept any
responsibility for the accuracy of the information or the consequences arising
from the application, use, or misuse of any of the information contained herein,
including any injury and/or damage to any person or property as a matter of
product liability, negligence, or otherwise. No warranty, expressed or implied,
is made in regard to the contents of this material. No claims or endorsements
are made for any drugs or compounds currently marketed or in investigative use.
The reader is advised to check product information (including package inserts)
for changes and new information regarding dosage, precautions, warnings,
interactions, and contraindications before administering any drug, herb, or
supplement discussed herein. | |