Frequently Asked Questions
What is a food allergy?
Food allergy occurs when the immune system mistakenly attacks a food protein. Ingestion of the offending food may trigger the sudden release of chemicals, including histamine, resulting in symptoms
of an allergic reaction.
The symptoms may be mild (rashes, hives, itching, swelling, etc.) or severe (trouble breathing, wheezing, loss of consciousness, etc.). A food allergy can be potentially fatal. Scientists estimate that approximately 12 million Americans suffer from food allergies, or one in 25. One in 17 children age 3 and under has a food allergy.
FAAN’s Do You Have a Food Allergy? brochure, distributed at health fairs throughout the country, is available thanks to a grant from the American College of Allergy, Asthma & Immunology (ACAAI).Download a copy.
What are the common symptoms of a reaction?
Symptoms may include one or more of the following: a tingling sensation in the mouth, swelling of the tongue and the throat, difficulty breathing, hives, vomiting, abdominal cramps, diarrhea, drop in blood pressure, loss of consciousness, and even death. Symptoms typically appear within minutes to two hours after the person has eaten the food to which he or she is allergic.
What is the best treatment for food allergy?
Strict avoidance of the allergy-causing food is the only way to avoid a reaction. Reading ingredient labels for all foods is the key to avoiding a reaction. If a product doesn’t have a label, individuals with a food allergy should not eat that food. If you have any doubt whether a food is safe, call the manufacturer for more information.
Is there a cure for food allergies?
Currently, there are no medications that cure food allergies. Strict avoidance is the only way to prevent a reaction. Many people outgrow their food allergies, although peanut, tree nuts, fish, and shellfish are often considered lifelong allergies. Research is being done in this area, and advances are being made. Click here for research information.
Should I stop eating a food if I think I’m allergic to it?
Removing a food from your diet can leave you with an unbalanced diet, which may cause other health problems. Seek a doctor’s assistance before making significant changes in your diet.
What is the best treatment for a food allergy reaction?
Epinephrine, also called adrenaline, is the medication of choice for controlling a severe reaction. It is available by prescription as a self-injectable device (EpiPen® or Twinject®). If you have been prescribed this medication, carry it with you at all times!
What is the difference between food allergy and food intolerance?
Many people think the terms food allergy and food intolerance mean the same thing; however, they do not. Food intolerance, unlike a food allergy, does not involve the immune system and is not life-threatening. Lactose intolerance, trouble digesting the milk sugar lactose, is a common example. Symptoms may include abdominal cramps, bloating and diarrhea.
A food allergy occurs when the immune system reacts to a certain food. The most common form of an immune system reaction occurs when the body creates immunoglobulin E (IgE) antibodies to the food. When these IgE antibodies react with the food, histamine and other chemicals (called “mediators”) are released, causing hives, asthma, or other symptoms of an allergic reaction.
What information should I provide my doctor when being evaluated for a possible food allergy?
Let your doctor know all of the details of any symptoms and their timing with relation to foods. It is often helpful to write down your observations and questions you may have so they can be discussed during the visit. If symptoms developed in association with a packaged food or restaurant meal, collect as many details as possible beforehand. For one to two weeks, you may wish to keep a food diary of everything you eat, the symptoms you experience, and how long after eating the symptoms occur. This information, combined with a physical examination and lab tests, will help the doctor determine which food, if any, is causing your symptoms.
What is the difference between a skin prick test and a blood test for allergy?
A skin prick test or a blood test are designed to measure a protein called IgE that is involved in many types of food allergic reactions. The tests detect the IgE antibodies that are specific for a particular food. The blood tests are most properly called “serum food-specific IgE tests” but are often called “RAST” (radioallergosorbent test) or referred to by various brand names.
A skin prick test is usually less expensive and can be done in the doctor’s office. The doctor places a drop of the substance being tested on the patient’s forearm or back and pricks the skin with a probe, allowing a tiny amount to enter the skin. If the patient is possibly allergic to the substance, a wheal (mosquito bite-like bump) will form at the site within about 15 minutes. The test is only slightly uncomfortable, generally not painful and there is no bleeding.
The blood test is sent to a medical laboratory, where tests are done with specific foods to determine whether the patient has IgE antibodies to that food. The results are usually received within one week.
Which test is better?
Although both tests are reliable, there are instances where your doctor may prefer one or another, and sometimes both are performed. A doctor might choose the blood test, for example, with a patient who has eczema or other skin problems that would make if difficult to read the results of a prick skin test. The results of either test are combined with other information, such as a history of symptoms to determine whether a food allergy exists. Sometimes, when tests and history are inconclusive, a supervised feeding test is performed under direct medical supervision (a food challenge) to definitively determine if there is an allergy.
It is important to know that allergy skin and blood tests do not necessarily show whether an allergy exists. Some allergies occur despite negative tests in part because some allergies do not involve IgE antibodies. Many times, a test is slightly positive but the person can eat the food without symptoms. Lastly, the tests do not tell how severe an allergy may be. This is why it is so important to work with your doctor (typically an allergist) to put together the history and test results to obtain a proper diagnosis.
Learn more about Food Allergy Testing.
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