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FOOD ALLERGY OVERVIEW — People with food allergies can have serious or even life-threatening reactions after consuming certain foods. The most important strategy in the management of food allergies is to avoid eating these foods.
However, it is not always easy to know if packaged foods or meals at restaurants contain allergens, so it is also crucial to know how to treat an allergic reaction if one happens.
This article will discuss tips for living with food allergies, potential non-food sources of allergens, and the importance of having a food allergy emergency action plan and being prepared to treat a reaction. The symptoms and diagnosis of food allergies and the use of epinephrine to treat serious allergic reactions are discussed separately. (See "Patient education: Food allergy symptoms and diagnosis (Beyond the Basics)" and "Patient education: Using an epinephrine autoinjector (Beyond the Basics)".)
GENERAL FOOD ALLERGY CONSIDERATIONS — People with food allergies are typically told to completely avoid that food. However, it is often difficult to do this in real life. As a result, anyone with food allergies must be prepared to treat an unexpected allergic reaction at any time and in any setting.
How careful do I need to be? — In general, people with food allergies must strictly avoid eating or drinking anything that contains even a minuscule amount of a food allergen. It is usually not possible to know what amount of the allergen will trigger an allergic reaction. Some people only react to a food they are allergic to if they drink alcohol, take nonsteroidal antiinflammatory drugs (NSAIDS; like aspirin or ibuprofen), or exercise shortly after eating that food. This can be managed by avoiding the "trigger" (eg, alcohol, medication, or exercise) for a period of time, usually at least a few hours, after consuming the food. Some people who have a reaction related to exercise also need to avoid exercise before eating particular foods. If you think you might have any of these triggers, talk to your allergist about what to do.
In some cases, a person can safely eat a food when it is cooked, but not in its raw form. (See 'What about cooked or baked products?' below.)
Eating, touching, and inhaling allergens — Most people with food allergies react after eating a food. Just touching the food may lead to localized skin reactions such as hives. However, this is unlikely to cause severe reactions in most people with food allergies.
Smelling foods is also unlikely to cause a severe reaction. As an example, the smell of peanut butter is related to volatile organic compounds (VOCs), substances that evaporate easily. The smell of peanut butter is not related to particles of peanut butter in the air, so it is not likely to trigger an allergic reaction.
However, inhaling tiny food particles (as a result of steaming, boiling, frying, grating, shedding, or grinding) can potentially trigger an allergic reaction in highly sensitive people. Thus, people who are very sensitive should avoid situations in which aerosolized food could be inhaled (for example, being in close proximity to boiling or steaming milk or shellfish or frying fish or eggs). Although peanut protein does not easily become airborne from peanut butter, it may from peanut flour or "dusty" roasted peanuts. Similarly, touching an allergenic food and then touching your eyes, nose, or mouth can cause an allergic reaction.
What about cooked or baked products? — Some people are able to tolerate an allergen if it is cooked or baked (ie, extensively heated). This is most commonly seen with milk/dairy, egg, fruits, and vegetables. Tolerance is typically determined through a controlled "food challenge," in which the person is fed increasing amounts of a baked food in a supervised clinical setting. If you or your child has successfully passed this challenge, these cooked and/or baked products should be introduced into the diet and consumed regularly.
LIVING WITH FOOD ALLERGIES — Adults and caregivers of children with food allergies must learn to carefully read food labels, prepare meals at home, and talk to others about their condition.
Managing allergies in school — If your child has a food allergy, you will need to provide the school with their medications and a copy of their food allergy action plan. Speak with the school nurse about the school's policies on managing allergies, for example, whether they have any rules about eating in the classroom or separating children with allergies at lunch time.
Food labeling — Laws regarding food labeling vary by country. People with food allergies must consider not only a food's ingredients, but also any potential cross-contact (also called "cross-contamination") that can occur as the food is prepared. It is also important to know that ingredients may change over time, and you should check labels each time you purchase a product, even if it's something you have had before.
In the United States, the Food Allergen Labeling and Consumer Protection Act mandates that nutritional labels on food packages clearly identify nine specified food allergy sources (milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, sesame, wheat, and soy), although other foods may still appear under multiple names. Additionally, for tree nuts, crustacean shellfish, and fish, the specific type (eg, walnut or cashew, shrimp or lobster, tuna or salmon, etc) must be labeled.
This law applies to all packaged foods manufactured in the United States and also to foods that are imported for sale in the United States. However, the law does not apply to packaged fresh meat, poultry, or egg products. Updates to this law are available online from the Center for Food Safety and Applied Nutrition, a branch of the US Food and Drug Administration (FDA; www.fda.gov/food).
Potential allergens other than the "top nine" listed above may still be listed on food labels with unclear names (for example, garlic may be listed as a spice, natural flavor, or even an artificial flavor). If the label is unclear, call the manufacturer to clarify the ingredients. The Food Allergy Safety, Treatment, Education, and Research (FASTER) Act of 2021 declared sesame as the ninth major food allergen recognized by the United States. This change resulted in the requirement to declare sesame on labels as of January 1, 2023. Products on store shelves labelled prior to that date will not include this declaration. Thus, some caution is needed during this transition period.
In addition, it is important to understand that "substitute" foods, which are used to remove fats or other components of a food, may not remove the allergenic proteins. As an example, some egg substitutes (which are lower in cholesterol) still contain egg white proteins.
Advisory labeling — A manufacturer may use certain phrases when a particular allergen is not an intended ingredient but the ingredient may come in contact with the food during the manufacturing process. As an example, a blueberry muffin may not intentionally contain nuts but may be made in a bakery where banana nut muffins are made. Manufacturers may use phrases such as "may contain," "processed in a facility with," "manufactured on shared equipment with," and others. There are no laws regarding when this type of label should be used.
Although manufacturers use a variety of label terms in their voluntary advisory warnings, these do not necessarily reflect the level of risk. As an example, a muffin that says that it "may contain nuts" is no more or less likely to contain nuts than a muffin that says "processed in a facility with nuts."
Advisory labeling may help to reduce the risk of an allergic reaction but may also significantly reduce the food choices available to people with food allergies. Most allergists recommend avoiding foods that have an advisory label because it is impossible to know the actual risk. Serious allergic reactions have occurred as a result of cross-contact. Ask your allergy specialist if this is a concern for you.
Alcoholic beverages — Alcoholic beverages may contain allergens. Labeling laws do not currently apply to these beverages. People with food allergies are advised to call the manufacturer if there are questions about the ingredients.
Preparing meals at home — Some families avoid bringing food allergens into the home if one person is allergic. Other families keep the food in the house but are careful to avoid cross-contact.
Avoiding cross-contact requires thoroughly cleaning utensils, cookware, glassware, storage containers, and other food preparation materials used with a food allergen before the item is used to prepare or serve "safe" meals. (See 'Cleaning' below.)
All members of the family, including children, must be careful if allergenic foods are brought into the house. As an example, if a child uses a single knife to prepare a peanut butter and jelly sandwich, they could introduce peanut allergen into otherwise safe jelly and subsequently cause a reaction in a peanut-allergic sibling who eats the jelly.
Other tips for preparing meals at home include preparing the safe meal first, keeping food containers covered to prevent spills, and designating specific containers of food for the allergic person only.
Cleaning — Washing food storage containers and dishes in a dishwasher or hand washing with hot water and liquid dish soap is generally adequate to remove food allergens.
Tabletops and other surfaces may be cleaned with a household cleaner or commercial wipe. Bar or liquid soap, but not alcohol-based antibacterial hand gel, can remove peanut allergen from adults' hands. Studies of other (non-peanut) food allergens have not been performed, although these cleaning methods are probably adequate for other allergens as well.
Traveling and eating out — Dining out can be challenging for people with food allergies. The table includes tips to ensure that the risk of contact with a food allergen is minimized (table 1).
Nuts are sometimes served on airplanes, increasing the risk of an allergic reaction. In addition, other travelers bring their own food on board. If you are traveling with a young child who has a food allergy, clean the tray tables and inspect the seating area for foods that your child might find and eat. Some airlines provide additional accommodations when requested in advance (eg, a flight where peanuts are not served).
FOOD ALLERGENS IN NON-FOOD ITEMS — Non-food items, such as medications, cosmetics, vaccines, and craft supplies, may contain ingredients normally found in foods. Labeling laws do not apply to these products. If there are questions about a product's ingredients, it is often helpful to call the manufacturer.
Vaccines — Gelatin, egg, and other potential allergens may be used in the production of certain vaccines:
●Gelatin – Gelatin is included in measles, mumps, rubella (MMR), varicella, yellow fever, zoster, some rabies, and some Japanese encephalitis vaccines.
●Egg – Egg protein is present in yellow fever vaccine. People with egg allergies can be given the egg-based influenza vaccine safely.
Medications — Nonprescription and prescription medications (in tablet, capsule, and inhaler form) can contain food allergens. Always talk to your doctor or pharmacist to make sure you understand what is in your medications.
One example is lactose, a sugar derived from milk. Although lactose used in medications is unlikely to contain milk proteins, some experts recommend that people who are highly allergic to milk avoid using products that contain lactose (for example, they can use metered dose inhalers rather than dry powder inhalers that contain lactose).
Cosmetics and crafts — Cosmetics may contain a variety of food-derived ingredients, including milk, nut oils, wheat, and soy. Craft items, such as modeling dough, may contain wheat. Egg white is sometimes used to smooth finger paints. If you have a question about a product's ingredients, call the manufacturer.
PERSONAL CONTACT AND FOOD ALLERGIES — Saliva and other bodily fluids can potentially expose an allergic person to food allergens. Kissing or sharing straws, glasses, or utensils are the most likely ways of spreading an allergen through saliva. Based upon a study of peanut butter, waiting several hours after eating an allergenic food and then eating a nonallergenic food(s) seems to reduce the level of allergen in the saliva; this is a good way for a nonallergic person to minimize risk to a person with an allergy.
It is theoretically possible to have a food allergy reaction after other forms of contact, such as sexual intercourse or a blood transfusion. However, this type of reaction is uncommon.
FOOD ALLERGY TREATMENT PLAN — Because it is not always possible to avoid food allergens, it is important to develop a plan for dealing with this type of emergency before it happens. Serious allergic reactions are often unexpected, develop suddenly, and require immediate treatment. This is discussed in more detail separately. (See "Patient education: Anaphylaxis treatment and prevention of recurrences (Beyond the Basics)".)
The best treatment for an anaphylactic reaction is epinephrine, which is available in a device that can be used to inject yourself or someone else. If you or your child has a severe food allergy, you will need to carry an autoinjector with you at all times. The use of epinephrine autoinjectors is also discussed separately. (See "Patient education: Using an epinephrine autoinjector (Beyond the Basics)".)
WHERE TO GET MORE INFORMATION — Your health care provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our website (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for health care professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Allergic and asthmatic reactions to food additives
Clinical manifestations of food allergy: An overview
Clinical manifestations and diagnosis of oral allergy syndrome (pollen-food allergy syndrome)
Management and prognosis of oral allergy syndrome (pollen-food allergy syndrome)
Diagnostic evaluation of IgE-mediated food allergy
Management of food allergy: Avoidance
Food allergy in schools and camps
Experimental therapies for food allergy: Immunotherapy and nonspecific therapies
Oral food challenges for diagnosis and management of food allergies
Primary prevention of allergic disease: Maternal diet in pregnancy and lactation
Respiratory manifestations of food allergy
Seafood allergies: Fish and shellfish
The impact of breastfeeding on the development of allergic disease
Food allergy in children: Prevalence, natural history, and monitoring for resolution
Anaphylaxis in infants
Management of food allergy: Nutritional issues
Influenza vaccination in persons with egg allergy
The following organizations also provide reliable health information.
(https://medlineplus.gov/foodallergy.html, available in Spanish)
●National Institute of Allergy and Infectious Diseases
●American Academy of Allergy Asthma and Immunology
●Food Allergy Research and Education
●American College of Allergy, Asthma, and Immunology
●American Academy of Pediatrics
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