More than 50 million Americans have an allergy of some kind. You probably know one of those people or are one yourself. Food allergies are estimated to affect 4% – 6% of children and 4% of adults, according to the Centers for Disease Control and Prevention.
Food allergy symptoms are most common in babies and children, but they can appear at any age. You can even develop an allergy to foods you have eaten for years with no problems.
The body’s immune system keeps you healthy by fighting off infections and other dangers to good health. A food allergy reaction occurs when your immune system overreacts to a food or a substance in a food, identifying it as a danger and triggering a protective response.
While allergies tend to run in families, it is impossible to predict whether a child will inherit a parent’s food allergy or whether siblings will have a similar condition. Some research does suggest that the younger siblings of a child with a peanut allergy will also be allergic to peanuts.
Symptoms of a food allergy can range from mild to severe. Just because an initial reaction causes few problems doesn’t mean that all reactions will be similar; a food that triggered only mild symptoms on one occasion may cause more severe symptoms at another time.
The most severe allergic reaction is anaphylaxis — a life-threatening whole-body allergic reaction that can impair your breathing, cause a dramatic drop in your blood pressure and affect your heart rate. Anaphylaxis can come on within minutes of exposure to the trigger food. It can be fatal and must be treated promptly with an injection of epinephrine (adrenaline).
While any food can cause an adverse reaction, eight types of food account for about 90 percent of all reactions:
Sesame is the 9th most common food allergen and is found in many popular dishes, including hummus, under the name “tahini.” According to the FDA, “Under the FASTER Act of 2021, sesame is being added as the 9th major food allergen effective January 1, 2023. Until that time, manufacturers do not have to list it as an allergen, although in most cases it must appear in the ingredient statement. An exception is when sesame is part of a natural flavoring or spice.”
Symptoms of an allergic reaction may involve the skin, the gastrointestinal tract, the cardiovascular system and the respiratory tract. They can surface in one or more of the following ways:
Most food-related symptoms occur within two hours of ingestion; often they start within minutes. In some very rare cases, the reaction may be delayed by four to six hours or even longer. Delayed reactions are most typically seen in children who develop eczema as a symptom of food allergy and in people with a rare allergy to red meat caused by the bite of a lone star tick.
Another type of delayed food allergy reaction stems from food protein-induced enterocolitis syndrome (FPIES), a severe gastrointestinal reaction that generally occurs two to six hours after consuming milk, soy, certain grains and some other solid foods. It mostly occurs in young infants who are being exposed to these foods for the first time or who are being weaned. FPIES often involves repetitive vomiting and can lead to dehydration. In some instances, babies will develop bloody diarrhea. Because the symptoms resemble those of a viral illness or bacterial infection, diagnosis of FPIES may be delayed. FPIES is a medical emergency that should be treated with IV rehydration.
Not everyone who experiences symptoms after eating certain foods has a food allergy or needs to avoid that food entirely; for instance, some people experience an itchy mouth and throat after eating a raw or uncooked fruit or vegetable. This may indicate oral allergy syndrome – a reaction to pollen, not to the food itself. The immune system recognizes the pollen and similar proteins in the food and directs an allergic response to it. The allergen is destroyed by heating the food, which can then be consumed with no
The primary way to manage a food allergy is to avoid consuming the food that causes you problems. Carefully check ingredient labels of food products, and learn whether what you need to avoid is known by other names.
The Food Allergy Labeling and Consumer Protection Act of 2004 (FALCPA) mandates that manufacturers of packaged foods produced in the United States identify, in simple, clear language, the presence of any of the eight most common food allergens – milk, egg, wheat, soy, peanut, tree nut, fish and crustacean shellfish – in their products. The presence of the allergen must be stated even if it is only an incidental ingredient, as in an additive or flavoring.
Some goods also may be labeled with precautionary statements, such as “may contain,” “might contain,” “made on shared equipment,” “made in a shared facility” or some other indication of potential allergen contamination. There are no laws or regulations requiring those advisory warnings and no standards that define what they mean. If you have questions about what foods are safe for you to eat, talk with your allergist.
Be advised that the FALCPA labeling requirements do not apply to items regulated by the U.S. Department of Agriculture (meat, poultry and certain egg products) and those regulated by the Alcohol and Tobacco Tax and Trade Bureau (distilled spirits, wine and beer). The law also does not apply to cosmetics, shampoos and other health and beauty aids, some of which may contain tree nut extracts or wheat proteins.
Avoiding an allergen is easier said than done. While labeling has helped make this process a bit easier, some foods are so common that avoiding them is daunting. A dietitian or a nutritionist may be able to help. These food experts will offer tips for avoiding the foods that trigger your allergies and will ensure that even if you exclude certain foods from your diet, you still will be getting all the nutrients you need. Special cookbooks and support groups, either in person or online, for patients with specific allergies can also provide useful information.
Many people with food allergies wonder whether their condition is permanent. There is no definitive answer. Allergies to milk, eggs, wheat and soy may disappear over time, while allergies to peanuts, tree nuts, fish and shellfish tend to be lifelong.
Be extra careful when eating in restaurants. Waiters (and sometimes the kitchen staff) may not always know the ingredients of every dish on the menu. Depending on your sensitivity, even just walking into a kitchen or a restaurant can cause an allergic reaction.
Consider using a “chef card” – available through many websites – that identifies your allergy and what you cannot eat. Always tell your servers about your allergies and ask to speak to the chef, if possible. Stress the need for preparation surfaces, pans, pots and utensils that haven’t been contaminated by your allergen, and clarify with the restaurant staff what dishes on the menu are safe for you.
Symptoms caused by a food allergy can range from mild to life-threatening; the severity of each reaction is unpredictable. People who have previously experienced only mild symptoms may suddenly experience a life-threatening reaction called anaphylaxis, which can, among other things, impair breathing and cause a sudden drop in blood pressure. This is why allergists do not like to classify someone as “mildly” or “severely” food allergic – there is just no way to tell what may happen with the next reaction. In the U.S., food allergy is the leading cause of anaphylaxis outside the hospital setting.
Epinephrine (adrenaline) is the first-line treatment for anaphylaxis, which results when exposure to an allergen triggers a flood of chemicals that can send your body into shock. Anaphylaxis can occur within seconds or minutes of exposure to the allergen, can worsen quickly and can be fatal.
Once you’ve been diagnosed with a food allergy, your allergist should prescribe an epinephrine auto-injector and teach you how to use it. You should also be given a written treatment plan describing what medications you’ve been prescribed and when they should be used. Check the expiration date of your auto-injector, note the expiration date on your calendar and ask your pharmacy about reminder services for prescription renewals.
Anyone with a food allergy should always have his or her auto-injector close at hand. Be sure to have two doses available, as the severe reaction can recur in about 20 percent of individuals. There are no data to help predict who may need a second dose of epinephrine, so this recommendation applies to all patients with a food allergy.
Use epinephrine immediately if you experience severe symptoms such as shortness of breath, repetitive coughing, weak pulse, hives, tightness in your throat, trouble breathing or swallowing, or a combination of symptoms from different body areas, such as hives, rashes or swelling on the skin coupled with vomiting, diarrhea or abdominal pain. Repeated doses may be necessary. You should call for an ambulance (or have someone nearby do so) and inform the dispatcher that epinephrine was administered and more may be needed. You should be taken to the emergency room; policies for monitoring patients who have been given epinephrine vary by hospital.
If you are uncertain whether a reaction warrants epinephrine, use it right away; the benefits of epinephrine far outweigh the risk that a dose may not have been necessary.
Common side effects of epinephrine may include anxiety, restlessness, dizziness and shakiness. In very rare instances, the medication can lead to abnormal heart rate or rhythm, heart attack, a sharp increase in blood pressure and fluid buildup in the lungs. If you have certain pre-existing conditions, such as heart disease or diabetes, you may be at a higher risk for adverse effects from epinephrine. Still, epinephrine is considered very safe and is the most effective medicine to treat severe allergic reactions.
Other medications may be prescribed to treat symptoms of a food allergy, but it is important to note that there is no substitute for epinephrine: It is the only medication that can reverse the life-threatening symptoms of anaphylaxis.
No parent wants to see their child suffer. Since fatal and near-fatal food allergy reactions can occur at school or other places outside the home, parents of a child with food allergies need to make sure that their child’s school has a written emergency action plan. The plan should provide instructions on preventing, recognizing and managing food allergies and should be available in the school and during activities such as sporting events and field trips. If your child has been prescribed an auto-injector, be sure that you and those responsible for supervising your child understand how to use it.
In November 2013, President Barack Obama signed into law the School Access to Emergency Epinephrine Act (PL 113-48), which encourages states to adopt laws requiring schools to have epinephrine auto-injectors on hand. As of late 2014, dozens of states had passed laws that either require schools to have a supply of epinephrine auto-injectors for general use or allow school districts the option of providing a supply of epinephrine. Many of these laws are new, and it is uncertain how well they are being implemented. As a result, ACAAI still recommends that providers caring for food-allergic children in states with such laws maintain at least two units of epinephrine per allergic child attending the school.
A food allergy will usually cause some sort of reaction every time the trigger food is eaten. Symptoms can vary from person to person, and you may not always experience the same symptoms during every reaction. Allergic reactions to food can affect the skin, respiratory tract, gastrointestinal tract and cardiovascular system. It is impossible to predict how severe the next reaction might be, and all patients with food allergies should be carefully counseled about the risk of anaphylaxis, a potentially fatal reaction that is treated with epinephrine (adrenaline).
While food allergies may develop at any age, most appear in early childhood. If you suspect a food allergy, see an allergist, who will take your family and medical history, decide which tests to perform (if any) and use this information to determine if a food allergy exists.
To make a diagnosis, allergists ask detailed questions about your medical history and your symptoms. Be prepared to answer questions about:
After taking your history, your allergist may order skin tests and/or blood tests, which indicate whether food-specific immunoglobulin E (IgE) antibodies are present in your body:
Your allergist will use the results of these tests in making a diagnosis. A positive result does not necessarily indicate that there is an allergy, though a negative result is useful in ruling one out.
In some cases, an allergist will recommend an oral food challenge, which is considered the most accurate way to make a food allergy diagnosis. During an oral food challenge, which is conducted under strict medical supervision, the patient is fed tiny amounts of the suspected trigger food in increasing doses over a period of time, followed by a few hours of observation to see if a reaction occurs. This test is helpful when the patient history is unclear or if the skin or blood tests are inconclusive. It also can be used to determine if an allergy has been outgrown.
Because of the possibility of a severe reaction, an oral food challenge should be conducted only by experienced allergists in a doctor’s office or at a food challenge center, with emergency medication and equipment on hand.