What is a food allergy?

A traditional food allergy is health condition involving the immune system, in which a person with a food allergy experiences adverse physical reactions to specific foods. Food allergies are distinctly different than food intolerances or sensitivities, and can cause more severe reactions.

What kinds of foods can cause allergic reactions?

Eight foods account for over 90% of food allergy reactions in the U.S.

• cow’s milk
• egg
• wheat
• soy
• fin fish
• shellfish (i.e. shrimp, lobster, crab)
• tree nuts (i.e. pecans, walnuts, cashews, almonds, pistachios, pine nuts, Brazil nuts)
• peanuts

How common are food allergies?

Estimates vary for the prevalence of food allergies in the U.S., but approximate numbers include up to 6-8% of children and 3% of adults.

What is anaphylaxis?

The definition of “anaphylaxis” is very broad to allow for a number of causes. Based on the Second Symposium on the Definition and Management of Anaphylaxis summary report, “Anaphylaxis is a serious allergic reaction that is rapid in onset and may cause death.”

What does an allergic reaction look like?

A reaction to a food can cause a variety of symptoms. Each time an individual experiences a reaction, the symptoms can vary, so it is important to be aware of all the possibilities. Symptoms can include:

• hives, rashes,
• itching, swelling of skin
• nausea, vomiting
• difficulty breathing, wheezing
• low blood pressure, loss of consciousness

How do I know if I have a food allergy?

A food allergy diagnosis is made based on the patient’s history and supported by food allergy testing, which may include blood tests or skin tests. An allergist is best qualified to make the diagnosis.

What's the difference between blood tests and skin tests?

Testing for traditional IgE mediated food allergies can be done with either blood testing (often called RAST or ImmunoCAP testing) or skin testing. Both can be helpful and both have advantages and disadvantages.

RAST (blood) tests measure the amount of allergic antibodies a person has to a particular food. They can be used to confirm an allergy if there is already a history of a reaction. A positive RAST test without a history of a reaction does not mean you have a food allergy. It's also important to know that a high RAST test result does not necessarily mean your food allergy is severe. Some individuals have very high RAST levels but relatively mild reactions, while other individuals have anaphylaxis with low RAST levels.

Skin tests can also confirm an allergy but their advantage is that they're more accurate at predicting whether you’ve outgrown your food allergy or not.

Could I have a non-traditional, less common food allergy?

Food Protein Enterocolitis Syndrome (FPIES) - A nontraditional food allergy most commonly seen in infants less than 6 months of age. The clinical picture is one where the child ingests particular food (more commonly cow’s milk, soy and rice) and within 1-3 hours after ingestion he/she develops vomiting which is intense and out of proportion to the amount of food eaten. The vomiting can go on for a number of hours and these children can drop their blood pressure, making this potentially life threatening. Regular blood allergy tests or skin test will not detect this type of food allergy. Diagnosis is made based on the history. This food allergy is often outgrown but usually not until 3+ years of age.

Eosinophilic Esophagitis - A nontraditional food allergy that starts in childhood but can persist until adulthood. Symptoms often include gastroesophageal reflux that can be severe and is often not completely helped by antacids. Chronic abdominal pain, heartburn, burping are other symptoms. Foods and environmental allergies are a contributing factor in some but not all cases. Skin testing to these allergens can identify potential triggers. Avoidance of the foods can help relieve symptoms. 

Food protein induced Proctocolitis - A nontraditional food allergy presenting in infants less than 6 months of age. The clinical picture is one of painless blood noted in the bowel movements. Usually there are a small number of blood streaks or mucous in the diapers. The most common trigger is cow’s milk. Having a breast-feeding mother avoid cow’s milk products often relieves the symptoms.

What is the treatment for allergic reactions?

For severe allergic reactions, the first line of treatment is injectable epinephrine (in the form of an EpiPen® or Twinject®). Anaphylaxis Action Plans should be written by physicians and given to patients to help them make decisions about handling potential reactions.

How does a person successfully avoid exposure to their allergens?

Avoidance of a food allergen includes structuring a person’s diet in a way that the implicated food(s) is removed, and there is no risk of cross contact with unsafe foods. That level of avoidance entails careful label reading, re-structuring food preparation in the kitchen, and educating friends, relatives, caregivers, and school personnel.

What is cross-contamination?

Cross-contamination occurs when an allergen is added to a safe food through the double use of utensils, cookware, or cutting boards.

Is there a cure for food allergies?

There is currently no cure for food allergies. A person diagnosed with food allergies must strictly avoid his/her allergens, and always carry emergency medications (epinephrine) to use in case of an accidental exposure.

What does the future hold for individuals with food allergies?

There is currently active research in progress, looking at oral desensitization, Chinese herbs, and possibly allergy shots. None of these treatments are available to the general public yet, except through research studies. Great hope lies in the research which may allow a more proactive approach to preventing food allergy reactions.