- About Food Allergies: Overview
- Peanut Allergy
- Egg Allergy
- Milk Allergy
- Shellfish Allergy
- Wheat Allergy
- Tree Nut Allergy
- Soy Allergy
- Fish Allergy
- Seed Allergy
- Food Allergen Labeling & Consumer Protection Act
- Anaphylaxis
- Diagnosis
- Unproven Diagnostic Tests
- Treatment
- Eosinophilic Esophagitis
Overview
If you or someone you care about has a food allergy, you’re not alone. The national Centers for Disease Control estimates that some 12 million Americans have food allergies of varying degrees of severity: 6% of children under age 3, and 3.5-4% of the overall population.
Having a food allergy shouldn’t stop you from enjoying life to the fullest. But it does present challenges for you and your family. Since we don’t yet have a medication that can prevent an allergic reaction, you will have to take every precaution to avoid problem foods. That means that you will have to make changes in your day-to-day life—at home and away, when eating out, at work or in school.
A reaction to food can range from a mild response to anaphylaxis, a severe, sometimes even life-threatening, condition. Fortunately, once an anaphylactic reaction starts, a medication called epinephrine can stop it in its tracks. You can protect yourself by learning the symptoms of a severe reaction and knowing what steps to take if you have one.
All this may sound complicated and scary, especially if you have just been diagnosed. But it’s important to remember that the overwhelming majority of people with food allergies lead healthy, active lives. Educating yourself, your family and friends, and others in your circle is the key to coping and living well with food allergies. We hope that, as you explore this site, you’ll find the information you need to do just that. This overview will help you get started.
What is a food allergy?
Who gets food allergies?
What are the symptoms of an allergic reaction?
How are food allergies diagnosed and treated?
Can you have a reaction after touching or smelling a problem food?
What is the difference between a food allergy and a food intolerance?
What can I do to avoid an allergic reaction to food?
What is a food allergy?
The job of the body’s immune system is to identify and destroy germs (such as bacteria or viruses) that make you sick. A food allergy results when the immune system mistakenly targets a harmless food protein (an allergen) as a threat and attacks it.
Specifically, if you have a food allergy, your immune system produces abnormally large amounts of an antibody called immunoglobulin E (IgE), which fights the “enemy” food allergen by releasing histamine and other chemicals. These chemicals cause the symptoms of an allergic reaction. If you are very sensitive to a certain allergen, eating even a tiny amount of a problem food can cause a severe reaction.
Although a person can be allergic to any food, eight allergens are responsible for 90% of all reactions:
In addition, allergies to seeds—especially sesame—seem to be increasing in many countries.
Who gets food allergies?
Food allergies affect children and adults of all races and ethnicity. Your risk is higher if you have a parent who suffers from any type of allergic disease (asthma, eczema, food allergies, or environmental allergies such as hay fever).
A food allergy can begin at any age. However, cow’s milk, egg, and soy allergies typically begin in childhood and eventually may be outgrown. In the past, most children outgrew these allergies by school age. A recent study, conducted by researchers at Johns Hopkins University School of Medicine, indicated that children are taking longer to outgrow milk and egg allergies. Fortunately, the majority are allergy-free by age 16.
Peanut and tree nut allergies, which also tend to develop in childhood, usually are life-long. In the U.S., approximately three million people report allergies to peanuts and tree nuts. A study showed that the number of children with peanut allergy doubled from 1 in 250 to 1 in 125 between 1997 and 2002.
Fish and shellfish allergies also tend to be life-long. More than 6.5 million adults are allergic to finned fish and shellfish.
Food allergies appear to be on the rise in all industrialized countries. The World Health Organization (WHO) describes them as “important health issues.” Interestingly, environmental allergies (e.g., hay fever) along with asthma and other diseases caused by a defect in the immune system, also have been increasing. Researchers worldwide are trying to discover the reason for the growing incidence of these diseases.
Learn more about food allergy research.
What are the symptoms of an allergic reaction?
An allergic reaction to food can affect the skin, the gastrointestinal tract, the respiratory tract, and, in the most serious cases, the cardiovascular system. Reactions can range from mild to the severe and potentially life-threatening condition known as anaphylaxis. Food-allergic reactions are estimated to send 125,000 Americans to emergency rooms every year. Of these, 14,000 have anaphylaxis and more than 3,000 are hospitalized.
The foods most likely to cause anaphylaxis are peanuts, tree nuts, and shellfish. People who have both asthma and a food allergy are at the greatest risk for severe reactions.
Mild symptoms may include one or more of the following: hives (reddish, swollen, itchy areas on the skin); eczema (a persistent dry, itchy rash); an itchy mouth; nausea or vomiting; diarrhea; abdominal pain; and nasal congestion or a runny nose.
Symptoms of anaphylaxis may include: obstructive swelling of the lips, tongue, and/or throat; trouble swallowing; shortness of breath or wheezing; turning blue; drop in blood pressure; loss of consciousness; chest pain; and/or a weak pulse. People sometimes use the terms “anaphylaxis” and “anaphylactic shock” interchangeably. This is incorrect: “Anaphylactic shock” means that a patient’s blood pressure has dropped to a dangerously low level—an extremely serious condition. However, any one of the symptoms listed in this paragraph is a sign of a dangerous reaction that requires urgent medical attention.
Thanks to the effectiveness of epinephrine and a growing awareness of the seriousness of food allergies, deaths from anaphylaxis are not common. Those at highest risk for fatal reactions appear to be teenagers or young adults who have both asthma and a food allergy and who do not receive epinephrine in time. The longer the delay in receiving this life-saving medication, the more severe a reaction is likely to become.
For this reason, anaphylaxis should always be treated as a medical emergency. If you have a food allergy, you should always carry self-injectable epinephrine and wear medical alert jewelry. At the first sign of a reaction, you should take your medication and call 911. Even if medication seems to control the reaction, you should get to an emergency room as quickly as possible so you can receive more care. These steps save lives, even in the most serious cases.
Learn more about anaphylaxis.
How are food allergies diagnosed and treated?
If you suspect that you have a food allergy, you should see an allergist for a definitive diagnosis. After reviewing your medical history in detail, your allergist may perform skin or blood tests to help determine which foods are causing the allergy.
Learn more about diagnosis.
There is no therapy that can prevent an allergic reaction, although promising research is underway. In addition to epinephrine (adrenaline), the primary treatment for anaphylaxis, there are several other medications that help control mild to moderate reactions and relieve symptoms.
Learn more about food allergy treatments.
Can you have a reaction after smelling or touching a problem food?
Yes—but it is reassuring to know that these reactions normally are far less severe than reactions caused by eating foods that contain allergens. Although it is possible to have a severe reaction in these circumstances, the risk is generally low.
Airborne, or inhalant, reactions occur when food proteins are released into the air, especially in confined spaces. If you can smell a problem food, it doesn’t necessarily mean you’re in any danger. For example, if your peanut-allergic teenager is having lunch with a friend who is eating a peanut butter sandwich, he is likely to be fine. Your son may be able to smell the peanut butter, but there are no significant peanut allergens in the air. On the other hand, if he’s watching TV with a roomful of friends who are cracking open peanut shells, he might have symptoms. That’s because the dust from the shells discharges allergens into the air.
Contrary to what some people believe, cooking food does not remove all traces of an allergen. In fact, being near problem foods while they are cooking can cause an inhalant reaction, because heat releases food proteins (from frying eggs, boiling milk, or steaming fish, for example) into the air. Small exposures to airborne food allergens are unlikely to result in severe symptoms, and once food has cooled off, it should be safe to be near the food.
Similarly, if an allergen touches your skin, you may have a localized reaction (e.g., itching, swelling, or redness), but it is unlikely that this type of contact will trigger a serious reaction. In a study of 30 children with peanut allergy, a small amount of peanut butter was rubbed on the skin. Some of the children experienced a mild redness and rash in the area that the peanut butter touched, but nothing more. If you do touch a problem food, however, it is important that you wash your hands, using soap and water. Otherwise, rubbing the food into your eyes might cause your eyelids to swell. Worse, if you put your hands to your mouth or eat another food that you have touched, you could have a serious reaction. For this reason, young children should be closely watched to be sure they don’t put contaminated objects in their mouths.
A study at New York’s Mount Sinai School of Medicine evaluated how long peanut stays in the mouth after a peanut meal. The study was done because of concerns about passionately kissing a partner who has eaten peanut. The researchers found that simple brushing and rinsing was not fully adequate to remove the allergen. They found that after four hours and a peanut-free meal, the allergen was not detectable. However, the researchers advised partners of food-allergic people to prevent problems by avoiding the allergen altogether.
What is the difference between a food allergy and a food intolerance?
Although food intolerances share some of the symptoms of food allergies, they do not involve the immune system. They can cause great discomfort but are not life-threatening. People with food intolerances are not able to digest certain foods because their bodies lack the specific enzyme needed to break down that food. For example, if you are lactose intolerant, you are missing the enzyme lactase, which breaks down lactose, a sugar found in milk and other dairy products. The words “gluten intolerance” are sometimes used to describe Celiac disease. However, Celiac disease does involve the immune system and can cause serious complications if left unchecked.
What can I do to avoid an allergic reaction to food?
Be vigilant! Read the ingredient labels on all packaged foods to make sure that they do not contain any allergens. If you’re not sure whether a product contains a problem ingredient, call the manufacturer to find out. When dining out, make sure the dishes you order are allergen-free. If you are in doubt about any food, don’t eat it. Remember, people sometimes are exposed to problem foods in spite of their best efforts and the good will of everyone around them. Be sure to carry your medication and wear emergency identification jewelry at all times.
At first, trying to cope with your food allergy may be overwhelming. There will probably be times when eating will feel like a difficult task, rather than a pleasure. But eventually, managing your food allergies will become part of your daily routine, and you’ll find that life is sweet—even if you do have to pass up those chocolate nut brownies!