How Food Allergy Is Treated

If you have been diagnosed with a food allergy, the simplest and most effective way to prevent a reaction is to avoid the foods that cause problems. This can be harder than it sounds given that there is no perfect test to diagnose food allergies. Even if a food allergen is identified, it can often be hidden in the foods you buy, making it all the more difficult to remain vigilant.

In some cases, medications may be needed to treat acute allergy symptoms. Mild to moderate food allergies often respond to over-the-counter antihistamines. Severe reactions may require an injection of epinephrine to prevent a potentially life-threatening, whole-body allergic reaction known as anaphylaxis, along with supportive care.

People at risk of anaphylaxis may benefit from immunotherapy, a procedure used to desensitize the immune system to a an inhalant or venom. Food immunotherapy (SLIT, OIT, EPIT,) is being utilized by some allergists, but it's not currently approved by the Food and Drug Administration (FDA).

A number of experimental drugs are also being studied to prevent or treat allergies in new and novel ways.

There is no cure for food allergies, nor are there any medications that can prevent reactions. The only sure-fire way to avoid an allergic response is to omit known food allergens from your diet. This is not always a straightforward process.

Skin-prick tests are used to diagnosed allergies and can used on any food allergen, including eggs, fish, milk, peanuts, shellfish, soy, tree nuts, and wheat. Similarly, elimination diets (in which suspected foods are removed from the diet and gradually reintroduced to see if a reaction occurs) don't always provide a clear picture of which foods are you are truly allergic to and which you are not.

Moreover, people with "true" food allergies are often cross-reactive to a wide range of other foods. These challenges can make avoidance diets both difficult to design and hard to adhere to.

At the early stages of treatment, it often helps to work with a certified dietitian to formulate a sustainable self-management strategy. This not only includes adhering to dietary restrictions but also learning how to read ingredient food labels and avoid cross-contamination.

The biggest challenge of any avoidance diet is the sudden and often extreme restriction of foods you cannot eat. If your reactions are severe or your allergy profile is anything less than certain, your doctor may throw a wide net over the foods you should no longer consume This may include foods, including spices, that are likely to cause a cross-reaction. 

Allergic cross-reaction occurs between closely related foods that the immune system sees at the same. Peanuts, soybeans and other legumes have high rates of cross-sensitization but low rates of cross-reactivity (5%). Fish and shellfish allergies don’t cross-react. These are completely different allergens. While this may suggest that you can no longer eat entire food groups—a daunting prospect for even the most severe allergy sufferer—most avoidance diets are not nearly so restrictive.

As such, the food you need to eliminate at the onset of an avoidance diet may be extensive but can be gradually whittled down once you gain better control over your symptoms.

This is why allergists will recommend keeping a food diary when first starting an avoidance diet. This not only allows you to track foods that cause problems but offers you the means to test cross-reactive foods in small amounts to see if a reaction occurs. (As a general rule, never test a cross-reactive food without first speaking with your doctor.)

By keeping an accurate record of your dietary history, you may be able to gradually expand the range of foods you eat (or find hypoallergenic alternatives you can tolerate). In the end, the more foods you can consume without incidence, the more likely you will be to adhere to the restrictions.

We live in a processed food culture. According to a 2016 study in the Journal of Nutrition, no less than 61% of calories consumed by Americans come from highly processed foods and beverages.

Beyond the nutritional concerns, eating packaged or processed foods increases the risk of exposure to hidden food allergens. This requires people to be especially vigilant when reading food labels. Even raw meats and dairy are subject to additives, preservatives, and flavorings to which you may be allergic.

Some food allergens are easier to spot than others. The Food Allergy Labeling and Consumer Protection Act of 2004 (FALCPA) mandates that manufacturers prominently indicate if any of the eight most common food allergens are included in their product, even if they are only additives. In addition, the manufacturer must state the specific type of nut, fish, or crustacean used so that the consumer can make an informed choice.

In addition, people with food allergies need to educate themselves about the alternative names of food allergens as well as certain everyday ingredients that contain allergens. Examples include:

• Dairy: Casein, caseinate, cheese, curds, ghee, kefir, lactalbumin, rennet, whey
• Egg: Albumin, globulin, mayonnaise, meringue
• Fish and shellfish: Crabsticks (processed pollack), crevette, puttanesca sauce (anchovies), scampi, Worcestershire sauce (anchovies)
• Peanuts and tree nuts: Marzipan, nougat, pignoli, satay sauce (peanuts)
• Soy: Edamame, miso, tempeh, tamari, textured vegetable protein (TVP), tofu
• Wheat: Bulgar, couscous, durum, einkorn, emmet, farina, Kamut, seitan, semolina, spelt

Although dairy, eggs, fish, peanuts, shellfish, soy, tree nuts, and wheat account for 90% of food allergies in the United States, less common ones can be just as serious. To be safe, you need to know the scientific and alternative names of any food to which may be reactive.

If you are prone to food allergies, you would need to take steps to avoid cross-contamination at home and in restaurants. Cross-contamination is a serious for some people, particularly those with peanut allergies. It is not uncommon, for example, to hear of reactions that occur with as little as 10 micrograms (0.001 milligrams) of peanut.

In households where a family member is at high risk of anaphylaxis, every effort should be made to control the types of food that can be brought into the house, including snacks or gifts from friends. Other measures may be needed, including:

• Limiting problematic foods to certain parts of the kitchen
• Having dedicated storage, preparation, and dining spaces for allergen and allergen-free foods
• Having allergen-free utensils, preparation spaces, containers, cabinets, and drawers
• Teaching everyone how to properly clean surfaces and store problematic foods

If planning to dine out at a restaurant, do not hesitate to call in advance to advise them if your dietary concerns. Gluten-free restaurants are generally well educated about the risks of cross-contamination and may be better able to accommodate your needs.

As a general rule, avoid salad bars, buffet-style restaurants, and ice cream parlors where the risk of cross-contamination is high.

Mild to moderate food allergies will commonly manifest with stomach pain, nausea, a runny nose, sneezing, and an itchy mouth or skin. Mild hives and diarrhea can also develop.

In cases like these, an over-the-counter oral antihistamine can often help. Also known as H1 blockers, antihistamines work by inhibiting the action of a chemical known as histamine that the immune system produces in response to an allergen.

These include first-generation (non-selective) antihistamines that tend to cause drowsiness and second-generation (peripherally-selective) antihistamines are non-drowsy. Among the choices:

• First-generation H1 blockers include Benadryl (diphenhydramine), Chlor-Trimeton (chlorpheniramine), and Tavist (clemastine).
• Second-generation H1 blockers include Allegra (fexofenadine), Claritin (loratadine), and Zyrtec (cetirizine).

Although both have been found to have similar efficacy in treating food allergies, first-generation drugs like Benadryl may be useful if the allergy symptoms interfere with sleep. By contrast, antihistamines like Zyrtec are more appropriate if you have to work or drive.

Other side effects of antihistamines include dry mouth, dizziness, nausea, restlessness, blurred vision, vomiting, and difficulty urinating.

Food allergies can sometimes be severe and require prescription medications, including injectable drugs used in anaphylactic emergencies.

Food allergies are the leading cause of anaphylaxis outside of a hospital setting in the United States. Even if you have had only minor allergy symptoms in the past, you can still develop anaphylaxis, often without warning.

Generally speaking, all severe food allergies are treated as medical emergencies even if they do not appear to be life-threatening. This is because the symptoms of anaphylaxis are highly unpredictable and can suddenly turn deadly if not treated immediately.

Epinephrine (adrenaline) is the first-line treatment for anaphylaxis and the only drug that can reverse acute symptoms. It is delivered by intramuscular injection into the thigh, ideally within minutes of the appearance of symptoms.

Epinephrine works by inducing vasoconstriction (the narrowing of blood vessels). This rapidly reverses the swelling of tissues and the often-severe drop in blood pressure. It also relaxes the muscles of airways, easing respiration.

The effects of epinephrine are fast, but they don't last long. Once injected, emergency medical attention is needed without exception.

Although anaphylaxis has been known to occur 24 hours after exposure to an allergen, it more often develops rapidly within minutes. Quicker reactions are generally more severe. If left untreated, anaphylaxis can lead to shock, coma, heart or respiratory failure, and death.

Side effects of epinephrine include rapid heartbeats, sweating, shakiness, nausea, vomiting, dizziness, and anxiety. Epinephrine should be used with caution in people with severe heart conditions, but its benefits in treating anaphylaxis almost universally outweigh the risks.

Once epinephrine has been delivered, other drugs may be needed to control the severe allergic reaction. Among the options:

• Corticosteroid drugs, like hydrocortisone or prednisone, may be given orally or intravenously (into a vein) to reduce inflammation and prevent a recurrence of symptoms.
• Intravenous antihistamines, such as diphenhydramine, may also be used to support the reduction of inflammation.
• Short-acting bronchodilators, popularly known as rescue inhalers, can be used to relieve asthma symptoms once epinephrine has been delivered. Inhalants like albuterol are especially useful.

Anyone who is at high risk of anaphylaxis should be prescribed a prefilled epinephrine auto-injector (like EpiPen or Symjepi) and taught how to use it.

Always check the expiration date of your auto-injector, note the date on your calendar, and ask your pharmacist about automated reminders when refills are needed.

Although the avoidance of food allergens remains the first-line approach to managing food allergies, newer therapeutic options are being explored. Food immunotherapy is among the most popular of these emerging interventions.

Known more precisely as allergen immunotherapy (AIT), the procedure involves the daily administration of a food allergen to gradually reduce your sensitivity. The allergen can either be given as a fixed-dose or in gradually increasing doses.

Fixed-dose AIT is delivered epicutaneously (using an adhesive patch applied to the skin)., which increasing-dose AIT is delivered either orally (by mouth) or sublingually (under the tongue). The choice of AIT is based on the type of food allergy you have.

According to a 2016 review of studies in the journal Children, oral AIT was by far the most effective of the three methods used and has been shown to successfully treat milk, egg, peanut, tree nut, fruit, and vegetable allergies. Daily allergen doses start at around 300 milligrams (mg) per day, gradually increasing to 4,000 mg per day.

By contrast, sublingual AIT was only moderately effective in treating milk, peanuts, hazelnut, and kiwi allergies, while epicutaneous AIT achieved variable results with milk and peanut allergies.

According to the investigators, between 70% and 90% of treated individuals were fully desensitized to the food allergens after AIT treatment. Infants and children achieved better desensitization rates than adults, who have a roughly 50/50 chance of overcoming a food allergy.

The effectiveness of treatment tends to increase the longer AIT is prescribed (between nine and 12 months). Side effects tend to mild to non-existent.

A number of experimental therapies are being studied that scientists hope will one day prevent or reduce the severity of food allergies.

One agent edging closer to approval is Palforzia, a standardized peanut powder product used to reduce peanut allergy symptoms in children ages 4 to 17 as part of oral AIT treatment. Palforzia is not intended to cure peanut allergies but is rather used on an ongoing basis to reduce the frequency and severity of symptoms as well as the risk of anaphylaxis.

The FDA is expected to approve Palforzia. The wholesale price is anticipated to be as high as $4,200 per year.

Complementary and alternative medicines (CAM) are widely used in the United States to treat all types of allergies. At present, there is little evidence that they offer any significant benefit to people with food allergies.

One of the more touted alternative therapies is a Chinese herbal remedy known as FAHF-2. The oral drug is based on the classical Chinese formula Wu Mei Wan and contains nine herbal ingredients, including gan giang (ginger) and dang gui (angelica root).

As with We Mei Wan, FAHF-2 is believed to treat a host of unrelated health conditions, including asthma, chronic diarrhea, endometriosis, glaucoma, insomnia, irritable bowel syndrome, and type 2 diabetes.

A 2016 study in the Journal of Allergy and Clinical Immunology reported that FAHF-2, taken three times daily for six months, appeared to alter the skin-prick response in 29 adults with a diagnosed food allergy. However, when compared to adults given a placebo, there was no improvement in either the frequency or severity of allergy symptoms.

Other studies have suggested that acupuncture can reduce the severity of hives or prevent the activation of basophils (specialized white blood cells that release histamine). Most of the supporting evidence is either small or of poor quality.

Given the limited research and potential harms, it is too soon to recommend any complementary or alternative therapy for people with food allergies.