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.). Scientists estimate that approximately 12 million Americans suffer from food allergies.

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 (.pdf ~ 30kb).

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®).

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?

For one to two weeks, 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 or RAST test?

The skin prick test or a blood test, such as the RAST (or radioallergosorbent test), is commonly used to begin to determine if an allergy exists. (The RAST is sometimes called the CAP-RAST or ImmunoCap test.)

A skin prick test is usually cheaper 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 needle, allowing a tiny amount to enter the skin. If the patient is allergic to the substance, a wheal (mosquito bite-like bump) will form at the site within about 15 minutes.

A RAST test requires a blood sample. The sample 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 one is better than the other. Many doctors use a RAST for young children or for patients who have 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 and a food challenge, to determine whether a food allergy exists. Learn more about Food Allergy Testing (.pdf ~70KB).

How is food allergy related to eosinophilic esophagitis?

Eosinophilic esophagitis (EE) is a disorder characterized by the infiltration of a large number of eosinophils, a type of white blood cell, in the esophagus (the tube connecting the mouth to the stomach). EE can be triggered by food allergies. Once a diagnosis of EE is confirmed, allergy testing is typically required. In many situations, avoiding the allergens that trigger the eosinophils will be an effective treatment. Skin allergy testing will include skin prick testing and may also include patch testing (to look for delayed reactions). To learn more about EE, please visit the American Partnership for Eosinophilic Disorders website at www.apfed.org.

Additional information

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