Know the basics
What is food allergy?
Food allergy is an immune system reaction that occurs soon after eating a certain food. Even a tiny amount of the allergy-causing food can trigger signs and symptoms such as digestive problems, hives or swollen airways. In some people, a food allergy can cause severe symptoms or even a life-threatening reaction known as anaphylaxis.
Food allergy affects an estimated 6 to 8 percent of children under age 3 and up to 3 percent of adults. While there’s no cure, some children outgrow their food allergy as they get older.
It’s easy to confuse a food allergy with a much more common reaction known as food intolerance. While bothersome, food intolerance is a less serious condition that does not involve the immune system.
How common is food allergy?
Food allergy is extremely common. It can affect patients at any age. It can be managed by reducing your risk factors. Please discuss with your doctor for further information.
What are the symptoms of food allergy?
For some people, an allergic reaction to a particular food may be uncomfortable but not severe. For other people, an allergic food reaction can be frightening and even life-threatening. Food allergy symptoms usually develop within a few minutes to two hours after eating the offending food.
The most common food allergy signs and symptoms include:
- Tingling or itching in the mouth
- Hives, itching or eczema
- Swelling of the lips, face, tongue and throat or other parts of the body
- Wheezing, nasal congestion or trouble breathing
- Abdominal pain, diarrhea, nausea or vomiting
- Dizziness, lightheadedness or fainting
In some people, a food allergy can trigger a severe allergic reaction called anaphylaxis. This can cause life-threatening signs and symptoms, including:
- Constriction and tightening of airways
- A swollen throat or the sensation of a lump in your throat that makes it difficult to breathe
- Shock with a severe drop in blood pressure
- Rapid pulse
- Dizziness, lightheadedness or loss of consciousness
Emergency treatment is critical for anaphylaxis. Untreated, anaphylaxis can cause a coma or even death.
Exercise-induced food allergy: Some people have an allergic reaction to a food triggered by exercise. Eating certain foods may cause you to feel itchy and lightheaded soon after you start exercising. In serious cases, an exercise-induced food allergy can cause certain reactions such as hives or anaphylaxis. Not eating for a couple of hours before exercising and avoiding certain foods may help prevent this problem.
Pollen-food allergy syndrome: In many people who have hay fever, fresh fruits and vegetables and certain nuts and spices can trigger an allergic reaction that causes the mouth to tingle or itch. In some people, pollen-food allergy syndrome — sometimes called oral allergy syndrome — can cause swelling of the throat or even anaphylaxis. Cooking fruits and vegetables can help you avoid this reaction. Most cooked fruits and vegetables generally don’t cause cross-reactive oral allergy symptoms.
There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.
When should I see my doctor?
Seek emergency treatment if you develop any signs or symptoms of anaphylaxis. You should contact your doctor if you have any of the following:
- Constriction of airways that makes it difficult to breathe
- Shock with a severe drop in blood pressure
- Rapid pulse
- Dizziness or lightheadedness
If you have any signs or symptoms listed above or have any questions, please consult with your doctor. Everyone’s body acts differently. It is always best to discuss with your doctor what is best for your situation.
What causes food allergy?
When you have a food allergy, your immune system mistakenly identifies a specific food or a substance in food as something harmful. Your immune system triggers cells to release antibodies known as immunoglobulin E (IgE) antibodies to neutralize the culprit food or food substance (the allergen). The next time you eat even the smallest amount of that food, the IgE antibodies sense it and signal your immune system to release a chemical called histamine, as well as other chemicals, into your bloodstream.
These chemicals cause a range of allergy signs and symptoms. They are responsible for causing allergic responses that include dripping nose, itchy eyes, dry throat, rashes and hives, nausea, diarrhea, labored breathing, and even anaphylactic shock.
The majority of food allergies are triggered by certain proteins in:
- Shellfish, such as shrimp, lobster and crab
- Tree nuts, such as walnuts and pecans
In children, food allergies are commonly triggered by proteins in:
- Tree nuts
There are a number of reactions to food that cause similar symptoms to a food allergy. Depending on the type of food intolerance you have, you may be able to eat small amounts of problem foods without a reaction. By contrast, if you have a true food allergy, even a tiny amount of food may trigger an allergic reaction.
Because a food intolerance may involve some of the same signs and symptoms as a food allergy does — such as nausea, vomiting, cramping and diarrhea — people may confuse the two.
One of the tricky aspects of diagnosing food intolerance is that some people are sensitive not to the food itself but to a substance or ingredient used in the preparation of the food.
Common conditions that can cause symptoms mistaken for a food allergy include:
- Absence of an enzyme needed to fully digest a food. You may not have adequate amounts of some enzymes needed to digest certain foods. Insufficient quantities of the enzyme lactase, for example, reduce your ability to digest lactose, the main sugar in milk products. Lactose intolerance can cause bloating, cramping, diarrhea and excess gas.
- Food poisoning. Sometimes food poisoning can mimic an allergic reaction. Bacteria in spoiled tuna and other fish also can make a toxin that triggers harmful reactions.
- Sensitivity to food additives. Some people have digestive reactions and other symptoms after eating certain food additives. For example, sulfites used to preserve dried fruit, canned goods and wine can trigger asthma attacks in sensitive people. Other food additives that could trigger severe reactions include monosodium glutamate (MSG), artificial sweeteners and food colorings.
- Histamine toxicity. Certain fish, such as tuna or mackerel, that are not refrigerated properly and that contain high amounts of bacteria may contain high levels of histamine that trigger symptoms similar to those of food allergy. Rather than an allergic reaction, this is known as histamine toxicity or scombroid poisoning.
- Celiac disease. While celiac disease is sometimes referred to as a gluten allergy, it isn’t a true food allergy. Like a food allergy, it does involve an immune system response, but it’s a unique immune system reaction that’s more complex than a simple food allergy. This chronic digestive condition is triggered by eating gluten, a protein found in bread, pasta, cookies, and many other foods containing wheat, barley or rye. If you have celiac disease and eat foods containing gluten, an immune reaction occurs that causes damage to the surface of your small intestine, leading to an inability to absorb certain nutrients.
What increases my risk for food allergy?
There are many risk factors for Food Allergy, such as:
- Family history. You’re at increased risk of food allergies if asthma, eczema, hives or allergies such as hay fever are common in your family.
- A past food allergy. Children may outgrow a food allergy, but in some cases it returns later in life.
- Other allergies. If you’re already allergic to one food, you may be at increased risk of becoming allergic to another. Likewise, if you have other types of allergic reactions, such as hay fever or eczema, your risk of having a food allergy is greater.
- Food allergies are most common in children, especially toddlers and infants. As you grow older, your digestive system matures and your body is less likely to absorb food or food components that trigger allergies. Fortunately, children typically outgrow allergies to milk, soy, wheat and eggs. Severe allergies and allergies to nuts and shellfish are more likely to be lifelong.
- Asthma and food allergy commonly occur together. When they do, both food allergy and asthma symptoms are more likely to be severe.
Factors that may increase your risk of developing an anaphylactic reaction include:
- Having a history of asthma
- Being a teenager or younger
- Waiting longer to use epinephrine to treat your food allergy symptoms
- Not having hives or other skin symptoms
Diagnosis & treatment
The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.
How is food allergy diagnosed?
There’s no standard test used to confirm or rule out a food allergy. Your doctor will consider a number of things before making a diagnosis. The following may help determine if you’re allergic to a food or if your symptoms are caused by something else:
- Description of your symptoms. Be prepared to tell your doctor a history of your symptoms — which foods, and how much, seem to cause problems — and whether you have a family history of food allergies or other allergies.
- Physical examination. A careful exam can often identify or exclude other medical problems.
- Food diary. Your doctor may ask you to keep a food diary of your eating habits, symptoms and medications to pinpoint the problem.
- Skin test. A skin prick test can determine your reaction to a particular food. In this test, a small amount of the suspected food is placed on the skin of your forearm or back. Your skin is then pricked with a needle to allow a tiny amount of the substance beneath your skin surface. If you’re allergic to a particular substance being tested, you develop a raised bump or reaction. Keep in mind, a positive reaction to this test alone isn’t enough to confirm a food allergy.
- Elimination diet. You may be asked to eliminate suspect foods for a week or two and then add the food items back into your diet one at a time. This process can help link symptoms to specific foods. However, this isn’t a foolproof method.
- Psychological factors as well as physical factors can come into play. For example, if you think you’re sensitive to a food, a response could be triggered that may not be a true allergic one. If you’ve had a severe reaction to a food in the past, this method may not be safe.
- Blood test. A blood test can measure your immune system’s response to particular foods by checking the amount of allergy-type antibodies in your bloodstream known as immunoglobulin E (IgE) antibodies. For this test, a blood sample taken in your doctor’s office is sent to a medical laboratory, where different foods can be tested. However, these blood tests aren’t always accurate.
- Oral food challenge. During this test, done in the doctor’s office, you’ll be given small but increasing amounts of the suspect food. If you don’t have a reaction during this test, you may be able to include this food in your diet again.
How is food allergy treated?
The only way to avoid an allergic reaction is to avoid the foods that cause signs and symptoms. However, despite your best efforts, you may come into contact with a food that causes a reaction.
For a minor allergic reaction, over-the-counter or prescribed antihistamines may help reduce symptoms. These drugs can be taken after exposure to an allergy-causing food to help relieve itching or hives. However, antihistamines can’t treat a severe allergic reaction.
For a severe allergic reaction, you may need an emergency injection of epinephrine and a trip to the emergency room. Many people with allergies carry an epinephrine autoinjector (EpiPen, Twinject, Auvi-Q). This device is a combined syringe and concealed needle that injects a single dose of medication when pressed against your thigh.
If your doctor has prescribed an epinephrine autoinjector:
- Be sure you know how to use the autoinjector. Also, make sure the people closest to you know how to administer the drug — if they’re with you in an anaphylactic emergency, they could save your life.
- Carry it with you at all times. It may be a good idea to keep an extra autoinjector in your car or in your desk at work.
- Always be sure to replace epinephrine before its expiration date or it may not work properly.
Lifestyle changes & Home remedies
What are some lifestyle changes or home remedies that can help me manage food allergy?
The following lifestyles and home remedies might help you cope with Food Allergy:
- Don’t assume. Always read food labels to make sure they don’t contain an ingredient you’re allergic to. Even if you think you know what’s in a food, check the label. Ingredients sometimes change. Food labels are required to clearly list whether they contain any common food allergens. Read food labels carefully to avoid the most common sources of food allergens: milk, eggs, peanuts, tree nuts, fish, shellfish, soy and wheat.
- When in doubt, say no thanks. At restaurants and social gatherings, you’re always taking a risk that you might eat a food you’re allergic to. Many people don’t understand the seriousness of an allergic food reaction and may not realize that a tiny amount of a food can cause a severe reaction in some people. If you have any suspicion at all that a food may contain something you’re allergic to, steer clear.
- Involve caregivers. If your child has a food allergy, enlist the help of relatives, baby sitters, teachers and other caregivers. Make sure they understand how important it is for your child to avoid the allergy-causing food and that they know what to do in an emergency. It’s also important to let caregivers know what steps they can take to prevent a reaction in the first place, such as careful hand-washing and cleaning any surfaces that might have come in contact with the allergy-causing food.
Research on alternative food allergy treatments is limited. However, many people do try them and claim that certain treatments help.
- Herbal remedies. A few small studies of herbal remedies have shown some benefit in reducing symptoms and preventing anaphylaxis, including some Chinese medicine formulas. However, there’s no reliable proof yet that these work. In addition, concerns exist about the quality of some herbal preparations from China. If you do take an herbal remedy, be sure to tell your doctor about it. It may affect test results or interact with other medications you take.
- Acupuncture and acupressure. There’s little academic research on acupuncture for food allergies, and the studies that do exist don’t show a clear benefit from these techniques. If you decide to try one of these treatments, be sure you work with an experienced and certified provider.
If you have any questions, please consult with your doctor to better understand the best solution for you.
Hello Health Group does not provide medical advice, diagnosis or treatment.
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Food Allergy. http://acaai.org/allergies/types/food-allergy. Accessed 10 Feb, 2017.
Food allergy. http://www.mayoclinic.org/diseases-conditions/food-allergy/basics/definition/con-20019293. Accessed 10 Feb, 2017.
Review Date: February 13, 2017 | Last Modified: February 13, 2017