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.

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.

• Family history of allergies, asthma, or atopic dermatitis
• Personal history of asthma, atopic dermatitis, or other allergies

• 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

• Food intolerance or food poisoning
• Seasonal or environmental allergies or asthma
• Mononucleosis
• Viral hepatitis
• Parasitic infection
• Urticarial vasculitis
• Skin malignancy
• Connective tissue disease

Physical assessment includes noting characteristic symptoms, signs, and pattern of reaction, as well as a history of past exposures and reactions to related foods.

The blood tests radioallergosorbent (RAST) and enzyme-linked immunosorbent assay (ELISA) are generally more useful in ruling out a food allergy than diagnosing one.

Blood tests reveal elevated levels of IgE antibodies or the presence of eosinophilia.

In rare cases of gastric inflammation, an upper GI series may be needed.

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.

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.

• 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.

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.

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.

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).

An experienced homeopath should assess individual constitutional types and severity of disease to select the correct remedy and potency.

Acupuncture may help restore normal immune function and reduce the hypersensitivity response.

Therapeutic massage may help reduce the effects of stress.

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.

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.

Some research suggests a link between food allergies and celiac disease, arthritis, chronic infection, depression, anxiety, and chronic fatigue.

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.

Nutritional support may safely relieve symptoms during pregnancy.

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