Allergy Questions and Answers

If you are atopic, or have a predisposition toward developing allergic reactions, your body may produce an antibody called Immunoglobulin E (IgE) that is specific to what causes your allergic reactions. Immunoglobulin E (IgE) is a protective mechanism that is produced when you exposed to a substance that your body views as a threat. These tests measure the amount of IgE to that specific substance in your blood. Your specific IgE test results are as personal and unique as your fingerprint and your healthcare professional can use your results to identify any underlying allergic triggers that may be contributing to your symptoms. It is a simple blood test that is easier and less risky to perform than a Skin-Prick Test (SPT) or Oral Food Challenge (OFC).

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Anyone experiencing allergy-like symptoms can receive specific IgE (sIgE) blood testing. For babies and very young children, one blood sample collection is often less traumatic than the several scratches of a skin-prick test (SPT).

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Unlike a skin-prick test, a blood test can be performed on anyone no matter the condition of their skin—even during an eczema flare-up. A blood test can also be performed on someone while currently on medication, including antihistamines. It is also safe to perform on someone who is pregnant.

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A whole allergen blood test shows what type of allergen you may be sensitized to, while an allergen component test can determine―down to the molecular level―what components (proteins) could be causing the reaction. Allergen components can help 1) assess the risk for suffering severe, systemic reactions versus experiencing more benign symptoms, 2) explain symptoms due to cross-reactivity, and 3) increase diagnostic accuracy. Both tests rely on a simple blood draw.

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If appropriate, a specific IgE test for allergen components can be prescribed by your healthcare provider.

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Many people confuse food allergies with a food intolerance. They have many similar symptoms, but they’re not the same thing, and the differences between the two are important. Food intolerances usually involve the digestive tract, with uncomfortable symptoms like bloating and cramping, but with no risk of anaphylaxis. However, food allergic reaction could be life-threatening, which makes avoiding the offending food extremely important.

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Yes, adults can develop food allergies. In a U.S. population-based survey, it was estimated that 26 million adults have a suspected food allergy.⁶ If you suspect you have a food allergy, it is important to talk to your healthcare provider and get tested to confirm the diagnosis.

I tell my patients to always read labels. If a patient has been diagnosed with an allergy (based on his or her clinical history and confirmatory testing), I always recommend strict avoidance of a diagnosed food allergen. This includes avoiding the “may contain” statement. Patients often ask me, “I have tolerated this ‘may contain’ product before, so can I continue to eat it?” My answer is always “no, it isn’t worth the risk.” ‘May contain’ should be treated the same as ‘definitely does.’

Food allergy reactions primarily occur via ingestion. Reactions to allergens can occur when the allergen comes into contact with your mucus membranes, which line your mouth, eyes, and nose. If you are in the same room as your food allergen, and you happen to get some of that allergen on you, you can have an allergic reaction if you touch your mouth, eyes, and nose. Some allergens can also become airborne when cooking. Shellfish is a good example of an allergen whose proteins can become airborne when cooking.⁷ If the allergens land on your mouth, eyes, and nose, they can trigger an allergic reaction.

If you have an allergy, your immune system overreacts to an allergen by producing antibodies called IgE. These IgE antibodies bind to cells that, when triggered by the allergen, release chemicals that cause an allergic reaction. This reaction usually causes symptoms in the nose, lungs, throat, gut, or on the skin. Specific IgE blood tests measure the presence of IgE in a person’s blood directly. Skin prick testing instead measures the consequence of having elevated IgE; it measures the wheal and flare response a person has in response to an allergen.

Each specific IgE molecule has a specific “radar” for a particular allergen. That is why some people are only allergic to milk (they only have the IgE antibodies specific to milk); while others have allergies to multiple allergens because they produce many more types of IgE antibodies.

No, testing cannot predict the severity of a reaction, since reactions can be different each time a person is exposed. However, based on clinical studies, allergen component testing can be used to help assess if someone is at risk of a more severe, systemic reaction or a mild reaction. Click here to learn more about the value of component testing and how it can help patients better understand their allergy.

Anaphylaxis is defined as a systemic (occurring throughout the body) allergic reaction typically involving two or more organ systems—which means two or more of the following symptoms: hives, swelling of lip or tongue, nausea/vomiting, diarrhea, lightheadedness, shortness of breath, sensation of throat closing or wheezing.⁸ However, if you experience any respiratory symptoms, this may qualify as anaphylaxis as well. These are symptoms such as the acute sensation that your throat is closing, or that you have shortness of breath.⁸

You should use epinephrine in the setting of a severe allergic reaction including anaphylaxis. There is a saying, “Use epi first and use epi fast.” Epinephrine is the first line treatment for anaphylaxis. It’s important to use epi and then call 911. Epinephrine works fast and you should experience improvement in symptoms within minutes.⁸ However, the effects of epinephrine are short lived and that’s why most epinephrine comes in a two pack, and that is also why calling 911 should be part of your emergency plan.

A detailed patient history remains paramount in the diagnosis of food allergy. Diagnosis of food allergy can be complicated. A combination of diagnostics is often used, including skin testing, specific IgE blood testing for the whole allergen, allergen component testing and oral food challenges. Oral food challenges are considered the gold standard and highly definitive,⁹ but risks of severe allergic reactions exist. Clinicians must take steps, including accurate pretest risk assessment, to mitigate that risk before initiating an oral food challenge.

Allergen component testing can help healthcare providers refine the diagnosis and help guide their decision.⁹ This information can offer more assurances when considering a food challenge.⁹ It’s a complicated decision. Clinicians don’t want to restrict a patient from normal eating without strong evidence, but they certainly don’t want to clear the patient to eat any foods that may trigger a reaction.