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Allergy FAQs 

You probably have questions about allergies and that’s why we’ve answered some of the most common questions below.



What is an allergy?

An allergy is when your immune system reacts to something that is harmless to most people. Generally, your immune system protects you from substances that can make you sick. But if you come into contact with something that your immune system views as a threat, it releases a chemical called histamine. This release of histamine and other substances is what causes allergy symptoms.

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What causes an allergic reaction?

Hundreds of ordinary substances can cause—or trigger—an allergic reaction. Among the most common things that can cause reactions are plant pollen, food, an insect sting, mold, dust mites, pet dander and medications.

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Who can develop an allergy?

Anyone can be affected by allergies, but some are more prone to them than others. Genetic and environmental factors play a role in a person’s susceptibility to developing allergies. While allergies are common in children, they can occur for the first time at any age.

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Is it possible to outgrow an allergy?

Some children stop reacting to allergens, like milk and egg, as they grow, but allergies to foods like nuts and fish tend to remain. It’s also possible to develop allergies at any age, even as an adult.

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How can a blood test help me know if I have allergies?

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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At what age can you have a blood test to help identify potential allergies?

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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What are the benefits to having a specific IgE blood test?

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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What is the difference between a whole allergen blood test and a component blood test?

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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How do I get an allergen component test?

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

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What is asthma?

Asthma is a chronic (long-term) lung disease that inflames and narrows the airways. Asthma causes recurring periods of wheezing (a whistling sound when you breathe), chest tightness, shortness of breath, and coughing. The coughing often occurs at night or early in the morning.

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What causes asthma?

Asthma and allergies often go hand-in-hand. The majority of people who have asthma suffer from allergies, too.1-3 Plus, allergies can trigger your asthma or make it worse. In fact, up to 90% of children and 60% of adults have allergies that may make their asthma worse.4,5 When allergies either trigger or worsen asthma, it’s known as allergic asthma or allergy-induced asthma.

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Who develops asthma?

Anyone, regardless of age, gender, race or socioeconomic status can be affected by asthma.

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Can asthma be cured?

There is no cure for asthma, so your best defense is to learn if you have underlying triggers and then limit your exposure to them. And while there’s a strong connection between allergies and asthma, there are many other triggers to be aware of, too. Some of the most common non-allergenic triggers are cold or dry air, exercise, exposure to cigarette smoke or strong scents, the flu and other respiratory infections. 

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Can reducing exposure to my allergic triggers help my asthma?

Yes. Reducing exposure to one or more of your allergic triggers may help reduce your symptoms. This can only be accomplished by working with your healthcare professional to understand your unique allergy profile.

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Dr. Lakiea Wright, a board-certified internist, allergist, and immunologist, answers the most commonly asked questions about food allergies.


What is the difference between food allergy and food intolerance?

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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Is it possible to develop food allergies as an adult?

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.

What’s the most important thing for newly diagnosed patients to know when it comes to reading food labels?

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.’

Can people have reactions to a food allergen by simply being in the same room as the allergen? In other words, can people have airborne allergic reactions?

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.

What does allergic sensitization mean in regards to my IgE test results?

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.

Can you tell how severe an allergic reaction will be based on skin- or blood-test results? What about component tests?

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.

What is anaphylaxis and how do know if I am experiencing it?

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

When should someone use epinephrine and how long does it take epinephrine to work?

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.

What informs your decision to have a patient participate in a food challenge?

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.

  1. Roberts G, Levi-Schaffer F, Gideon Lack, FRCPCH. Food allergy as a risk factor for life-threatening asthma in childhood: A case-controlled study. J Allergy Clin Immunol. 2003;112:168-174. 
  2. Liu AH, Levi-Schaffer F, Gideon Lack, FRCPCH. Food allergy as a risk factor for life-threatening asthma in childhood: A case-controlled study. J Allergy Clin Immunol. 2010;126:798-806 e13. 
  3. Murray CS, Poletti, G, Kebadze T et al. Study of modifiable risk factors for asthma exacerbations :virus infection  and allergen exposure increase the risk of asthma hospital admissions in children. Thorax. 2006;61:376-382. 
  4. Allen-Ramey F, Schoenwetter W, Weiss T et al. Sensitization to Common Allergens in Adults with Asthma. J Am Board Fam Pract. 2005;18(5):434-439. 
  5. Host A,Halken. S. The role of allergy in in childhood asthma. Allergy. 2000;55:600-608. 
  6. Gupta RS, Warren CM, Smith BM, et al. Prevalence and Severity of Food Allergies Among US Adults. JAMA Netw Open. 2019;2(1):e185630. 
  7. Davis CM, Gupta RS, Aktas ON et al.  Clinical Management of Seafood Allergy. J of Allergy and Clinical Immunology:In Practice. 2020; 8(1); 37-44.
  8. Sicherer SH, Simons ER. AAP section on Allergy and Immunology. Epinephrine for First-aid Management of Anaphylaxis.  Pediatrics. 2017; 139(3).
  9. LaHood NA, Patil SU.  Food Allergy Testing.  Clinics in Laboratory Medicine. 2019; 39(4): 625-642.