What is a food allergy?
A food allergy is a reaction by the body’s immune system to something you ate or drank. Food allergies are more common in young children and in people who have other allergies, such as hay fever and eczema (dry skin rash). Food allergies must be taken seriously. Very tiny amounts of a food can cause a reaction if you are allergic to it. A severe reaction can be sudden and life threatening.
How does it occur?
A food allergy occurs when the body’s immune system mistakenly believes that a harmless substance (a food) is harmful. In order to protect the body, the immune system creates substances called antibodies to that food. The next time you eat that particular food, your immune system releases huge amounts of chemicals, such as histamines, to protect the body. These chemicals trigger symptoms that can affect the respiratory and cardiovascular systems, gastrointestinal tract, and skin.
Many different foods can cause an allergic reaction. The foods that most often cause a reaction are:
- cow’s milk
- tree nuts, such as walnuts and cashews
- People who have asthma have an increased risk of a severe or fatal reaction.
What are the symptoms?
Reactions differ. They may happen right away or not for several hours. Symptoms may be mild, or they might be life threatening when the allergy causes breathing problems.
The symptoms of an allergic reaction depend on the type and severity of the reaction. Common symptoms of an allergy are:
- itchy, watery eyes
- stuffy or runny nose
- swelling–for example, swelling of the eyelids
- a rash or hives (raised, red, itchy areas on the skin)
- stomach cramps
Some of the symptoms of a severe allergic reaction are:
- trouble breathing, including wheezing
- swelling of the lips, tongue, or throat
- hives (itchy, blotchy, raised rash)
- feeling dizzy or faint
- nausea, vomiting, or diarrhea
The symptoms of a severe reaction generally occur within minutes to 2 hours after contact with the food causing the reaction. In rare instances symptoms may occur up to 4 hours later.
Some fresh fruits and vegetables can cause a mild allergic reaction called oral allergy syndrome. The itching or tingling of the mouth that occurs is not a true allergy. Instead, it is the result of cross-reactivity: These foods contain some of the same proteins that are found in certain pollens that you may be allergic to. For example, if you are allergic to ragweed, you may react to eating melons and bananas. An allergy to birch pollen may cause a reaction to apples, plums, and nectarines.
How is it diagnosed?
Your healthcare provider will ask about your personal and family history for allergies. You will be asked about your symptoms and the foods you eat. If your symptoms are not severe, your provider may suggest that you try to find which foods cause your symptoms by not eating certain foods for a while. Then you can carefully try eating these foods again, one at a time, to see if your symptoms come back. Ask your provider which foods you should avoid at first.
Your healthcare provider may recommend that you keep a food diary. This involves recording all of the food you eat and drink, when you eat or drink, and any symptoms you have.
If your symptoms are severe and there is no obvious cause, then it may be possible to have allergy skin tests or blood tests for common food allergies such as egg, cow’s milk, nuts, and shellfish.
How is it treated?
Mild symptoms may not need treatment. Or your healthcare provider may prescribe antihistamine medicine for you to use as needed.
For moderate symptoms your provider may also prescribe a steroid medicine for you to use for a few days. Using a steroid for a long time can have serious side effects. Take steroid medicine exactly as your healthcare provider prescribes. Don’t take more or less of it than prescribed by your provider and don’t take it longer than prescribed. Don’t stop taking a steroid without your provider’s approval. You may have to lower your dosage slowly before stopping it.
For severe reactions, you will need a shot of epinephrine. You may need additional medicine, depending how severe your reaction is. You should be watched wherever you are treated for 4 to 6 hours to make sure that the symptoms do not come back after the effects of the medicine have worn off.
Once your reaction has been successfully stopped, you should ask what food or foods most likely caused the reaction. You should avoid those foods until you have follow-up with your primary healthcare provider or an allergist.
How long will the effects last?
The effects of the allergic reaction last from several minutes to hours, depending on how much of the food you ate, the severity of your allergy, and how quickly you received treatment.
Some food allergies are outgrown while others are lifelong. Most children who are allergic to milk, eggs, soy, and wheat outgrow their allergies. However, allergies to peanuts, nuts, fish, and shellfish are almost never outgrown.
How can I take care of myself and help prevent another allergic reaction to food?
The only way to not have a reaction is to avoid the food that causes the allergy symptoms. When you know you are allergic to a specific food, you should avoid eating that food. Be sure to check the ingredients on food package labels and ask about the ingredients in foods prepared in restaurants when you eat out.
If you are breast-feeding a baby that has a food allergy, stop eating or drinking the food your baby is allergic to. Food allergens can get into your breast milk.
Follow all of your healthcare provider’s instructions.
Keep a record of all reactions you have to food or drink.
Substitute soy-based products for milk if you are allergic to milk but not to soy. If you are allergic to both milk and soy, substitute rice milk or nut-based milk. Look for rice or nut milks that are calcium enriched.
If you tend to have severe food allergy reactions, you should ask your healthcare provider about carrying medicine with you for emergency use, such as shots of epinephrine (EpiPen).
Tell others about your allergy–what you need to avoid, the symptoms of an allergic reaction, and how they can help if you are having a severe reaction.
Wear a medical ID bracelet or necklace that notes your allergy. Or you carry a card with this information in your wallet or purse.
Call 911 for emergency help if you have sudden, severe food allergy symptoms or your symptoms do not get better and you start having throat tightness or trouble breathing.
For more information, contact:
The Food Allergy & Anaphylaxis Network (FAAN)
Phone: (800) 929-4040
Web site: http://www.foodallergy.org.
The American Academy of Allergy, Asthma and Immunology
Web site: http://www.aaaai.org
How can I keep from having a food allergy?
There is no cure for food allergy, but research is ongoing. There are studies that suggest that gradual exposure to some food allergens may allow some tolerance to that food. These challenges should be done only under medical supervision, and this possible treatment for food allergy is still being studied. The current recommendation is that the only way to keep from having an allergic reaction is to avoid the food that causes it.
Feeding babies only breast milk for the first 4 to 6 months of life is recommended to help lower the risk of food allergy.
Patient story: Milk and egg allergy
The mother of a nine-year-old boy tells: My son is allergic to a lot of things, but the worst is the allergy to milk and egg. Just a tiny bit of milk in a chocolate pastille is enough to make him ill.
When he was three months old the problems with breathing started and the paediatrician diagnosed him having asthma. After that his milk allergy was diagnosed. He was very sensitive and small amounts of milk in the food got his nose running and gave him nettle rash. When nine month of age he got scrambled eggs for the first time.
A serious attack of nettle rash followed so the family assumed that he was also allergic to egg. Once a year he is challenged with milk and egg to see if his allergy is still there or he has outgrown the allergy. It takes 8-10 days before he is back to his normal self after these provocations.
Patient story: Peanut allergy
The mother of a five-year-old girl tells: My daughter has peanut allergy. She is so sensitive that just a very small amount of peanut is life threatening. She started getting asthma and nettle rash just before her 3 years birthday. Often, when I picked her up in kindergarten, part of her face and her ears, lips and around the eyes was swollen. The lung function was low and she got large amounts of asthma medicine. When she was tested for ordinary allergies the test was negative. Normally she would be fine at home but get symptoms in kindergarten.
At a birthday party she got a peanut for the first time. She did not chew it, but spat it out immediately, because she did not like the feeling in the mount. A few moments later her tongue, lips and eyes swelled, the nose began to run and she began to cough and had difficulty breathing. She was ill to an extent we had not seen before. We ended up in the local emergence room.
A new allergy test showed that she was severely allergic to peanuts. We assume that the symptoms in kindergarten can be explained by her being exposed to peanut via the other children. There are peanuts in many foods such as breakfast cereals, biscuits, cakes, ice cream and candy.
We were overwhelmed when we realised that we had to be very careful with even traces of peanuts in food. We now have an ‘epi-pen’ that contains adrenalin that my daughter shall have if she ingests peanut inadvertently. This is to prevent anaphylaxis.
What is food allergy testing?
Food allergy testing is a way to check your body’s reaction to certain foods. Along with a medical history and physical exam, one or more of the following tests may be done to see what foods you may be allergic to:
- skin prick test
- blood test
- elimination diet
- food challenge test
- Why is it done?
If you have a history of allergic symptoms after eating certain foods, your healthcare provider may recommend that you have tests to check for food allergies. This will help you know which foods you should avoid eating to prevent an allergic reaction.
You may need to be tested for food allergies if you have some of the following symptoms shortly after eating:
- redness of the skin
- swelling of the lips or eyelids
- throat tightness
- wheezing or other breathing trouble
- vomiting or diarrhea.
How do I prepare for the tests?
You may need to avoid taking certain medicines before the tests because they might affect the test result. For example, you may need to stop taking any antihistamines one to several days before the tests. Make sure your healthcare provider knows about any medicines, herbs, or supplements that you are taking. Don’t stop any of your regular medicines without first consulting with your healthcare provider. Talk to your healthcare provider if you have any questions.
How are the tests done?
One or more of the following tests may be done.
Skin prick test: A skin prick test is often used to help identify food allergies. For this test, a drop of food extract is put on the skin and then the skin is pricked with a small needle through the drop of the food extract. The test can also be done with a pricking device that has been presoaked in the food extract. Only the top layer of skin is pricked. The test is usually done on your back or arm. The skin test is ready to check in about 15 minutes. You may be allergic to the food in the extract if a red bump that looks like a mosquito bite appears at the spot where the food extract was placed. This test by itself is not enough for diagnosis of a food allergy.
Blood test (RAST test): Blood tests are not done as often as skin prick tests, but they can be useful at times. The RAST test checks a sample of your blood for antibodies your body makes when it is trying to fight off allergy-causing substances in food (allergens). This test by itself is also not enough for a diagnosis.
Misleading results can occur with both skin and RAST tests. That is, the test may indicate that you are allergic to a food that further tests show you are not allergic to (false positive results). A food challenge test may be necessary to confirm the results.
Elimination diet: Your healthcare provider may ask you to stop eating foods you may be allergic to for a week or two. Then you will add the foods back into your diet one at a time. This process can help connect your symptoms to specific foods. During this time, you will need to keep a record of the foods you eat and any symptoms you have. If you have had a severe reaction to foods, this method cannot be used for diagnosis.
Food challenge: A food challenge test is the best way to diagnose a food allergy. The test is usually done in your healthcare provider’s office. Sometimes it is done in the hospital. To do the test, you are given gradually increasing amounts of a food–either in colorless capsules or in a slush or pudding–while your provider watches for symptoms. This test should be done only by a trained professional who is ready to treat you if you have a serious reaction to the food. If you have symptoms of an allergy after the challenge that fit with your medical history and other test results, the diagnosis can be made.
How will I get the test result?
Ask your healthcare provider how you will get the result of your skin prick or blood test.
What do the test results mean?
If the skin or blood test is negative for a food, then you probably do not have an allergy to that food.
If the skin test is positive for a certain food, it may mean you are allergic to that food.
Sometimes the test can be positive even if you are not allergic to the food. The positive test result can be wrong sometimes because:
You can sometimes continue to have a positive test result for many years to a food allergy you have outgrown.
You are allergic to a different food or nonfood that has some components similar to the food you were tested for. For example, you might have a positive test for soy if you have peanut allergy, or a positive test to wheat if you have a grass pollen allergy.
Remember that test results are only one part of a larger picture that takes into account your medical history and current health. It’s important to confirm a suspected food allergy with careful testing and diagnosis. Many presumed food allergies are not really allergies.
- Tips to Remember Food Allergy http://www.aaaai.org/patients/publicedmat/tips/foodallergy.stm dated copyright 2010. accessed 4-29-2010.
- Food Allergy Symptoms http://www3.niaid.nih.gov/topics/foodAllergy/PDF/foodallergy.pdf Mayoclinic.com dated 2/14/09 accessed 4-29-2010.
- Food Alleries: What you Need to know Food Facts FDA 8-20-09 accessed http://www.fda.gov/Food/ResourcesForYou/Consumers/ucm079311.htm 4-29-2010.
- Food Allergens http://kidshealth.org/teen/food_fitness/nutrition/food_allergies.html# Kids health.org 1/2008 accessed 4-29-10.
- Allergic reactions http://www.nlm.nih.gov/medlineplus/ency/article/000005.htm. 4-2008 accessed 4-29-10.
- National Institute of Allergy and Infectious Diseases. “What’s in It for Patients?” National Institute of Allergy and Infectious Diseases Home Page. National Institute of Allergy and Infectious Diseases, 03 Dec. 2010. Web. 28 Dec. 2010. <http://www.niaid.nih.gov/topics/foodAllergy/clinical/Pages/patients.aspx>.
- “Food Allergy An Overview.” NIAID.gov. NIH NIAID, Nov. 2010. Web. 20 June 2011. <http://www.niaid.nih.gov/topics/foodAllergy/Documents/foodallergy.pdf>.
Riviera Allergy Medical Center offers general treatment for asthma, asthma treatment for children, skin allergy treatment, allergy asthma relief, allergy and asthma care, testing for food allergies and much more. Located in the South Bay, the allergy and asthma center is headed up by renowned seasonal allergy treatment specialist Dr. Ulrike Ziegner. The center safely administers allergy shots for those seeking seasonal allergy relief.
These are some of the things you will learn by visiting the Riviera Allergy Medical Center. If you are having problems with your allergies, you may benefit from a trip to see Dr. Z. Give us a call (310) 792-9050 or visit us at 1711 Via El Prado, Suite 101, Redondo Beach, CA 90277. We’re located in the heart of Riviera Village. See Map. www.RivieraAllergy.com
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