What is a trigger?
A trigger can be allergic or non-allergic, and is basically anything that causes you to have allergy-like symptoms.
What are common allergy symptoms?
Allergy symptoms affect your nose and lungs, which are part of your respiratory (breathing) system. Many times these symptoms are referred to as “hay fever” or sometimes just plain "allergies". The most common nasal symptoms are congestion, sneezing, coughing, and itchy-watery eyes. The most common lung symptoms are coughing, wheezing, shortness of breath, and chest tightness. When you have one or more of these symptoms, allergic triggers can make your symptoms worse.
What are common triggers?
Triggers come from many different sources. Common triggers include pet dander, pollen in the air, mold, pollution, smoke, grass, and trees - even exercise can be a trigger.
Can I be allergic to more than one allergen?
Yes. Most people with allergies are allergic to more than one allergen. Their symptoms might appear only when they are exposed to two or more triggers at once.
Can I guess my triggers based on my symptoms?
Not necessarily. Symptoms can be caused by many different allergic or non-allergic triggers. Using symptoms like congestion, sneezing, coughing, or wheezing to guess your triggers is not very helpful. There are many possible inhalant allergic triggers (indoor and outdoor, seasonal and perennial), so if you are allergic and you try to guess your allergic triggers, you might guess wrong. You also won’t have the whole picture.
If I have asthma, should I be checked for allergies?
Yes. That’s because if you have both conditions and the allergies go untreated, the combination could damage your delicate airways. Research shows that the majority of people with asthma (up to 60% of adults and up to 90% of children) also have allergies (1-3). Testing to identify your allergic triggers will help you and your healthcare provider better manage your symptoms.
How can a blood test help me know if I have allergies?
If you have allergies, your body produces an antibody called IgE that is specific to your allergic triggers. The blood test measures the amount of your IgE. Your healthcare provider can use your test results to identify the specific allergic triggers that may be contributing to your symptoms. Your specific IgE test results are as personal and unique as your fingerprint. After you receive your test results, you should review them with your healthcare provider and create a tailored plan to help reduce your exposure to your specific allergic triggers.
What are the benefits of having the allergy blood test?
- The test results will help you and your healthcare provider customize a treatment approach that’s right for you.
- Knowing your allergic triggers can help you take control and reduce your symptoms.
- Normal or negative results can help your healthcare provider rule out allergies in order to consider other possible triggers.
- A blood test requires only one blood sample.
Does reducing exposure to my allergic triggers help?
Yes. Reducing exposure to one or more of your allergic triggers can help reduce your symptoms and your need for medication (4). This can only be accomplished by working with your healthcare provider to learn your unique allergy profile.
What is the difference between food allergy and food intolerance?
It is common to confuse the terms food allergy and food intolerance. However, they do not mean the same thing. Food intolerance, unlike 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 usually include bloating, abdominal cramps and diarrhea.
Food allergy, on the other hand, does involve the immune system. It occurs when the body produces IgE antibodies to a certain food. Common symptoms are hives and asthma.
Can an allergic patient develop allergies to new allergens throughout life?
The development of allergy in relation to age can be described as an "allergy march". This means that there is often a given direction, once atopic immune responses associated with IgE antibodies have been initiated and induced the atopic state.
The manifestation of atopic disease varies considerably with the age of the child, as do the allergens involved. In infancy allergies to foods seem to be the most common, after the age of 3 allergy to inhalant becomes predominant. New causative allergens could be added due to higher concentrations of exposure, or as quite new allergens. However, the immune system tends to be less active in older days (5).
What is the prevalence of allergy?
Around 35% of the population have allergic symptoms, although the frequency of allergy may vary from country to country.
Why do some people become allergic and others not?
Genetic factors determine how easily and how strongly the individual will become sensitized and how much IgE antibodies will be produced. Sensitization, inflammation and irritation of tissue may develop differently in individual patients, subsequent to different exposures.
Why is it not possible to test for contact dermatitis with a blood sample?
Contact dermatitis is not mediated by antibodies but by lymphocytes. Instead a patch-test with a panel of suspected antigens can be used. It is put on the back of the patient for 48 hours and the reactions are finally read after 72 hours. (This type of reaction is also called delayed hypersensitivity).
Is it possible to "grow out" of allergy?
The child usually grows out of milk and egg white allergy, while allergies to foods such as nuts and fish tend to remain in later years. Specific IgE-antibodies to food allergens in younger years constitute an early predictor for developing atopic disease and for IgE production to inhalant allergens later in life.
What is the incidence of allergy to drugs?
The incidence of adverse reactions to drugs of the overall adult population is estimated to be around 15%. Numerous mechanisms are implicated in drug allergy and the incidence of immediate drug reactions (Type I) seems to be very low in comparison with allergy to more common allergens such as pollens and pets. The incidence of allergy to penicillins is 1/1000 administrations, i.e. 0.7 to 10% of treatments (6).
Can you become allergic as an adult, even if you have never been so before?
Yes, one can become allergic throughout life, but the symptoms more often occur early in life. However, it could happen later in life due to the introduction of new allergens or an increased allergen load.
Do skin prick tests (SPT) and IgE determinations give different results?
Skin tests and blood tests are both used to diagnose IgE-mediated reactions to allergens. Under ideal conditions, skin prick testing (SPT)provides results concordant with optimized in vitro IgE antibody tests. However, skin tests are not quantitative, and the result cannot be compared between clinics. In contrast to blood tests, skin tests depend on the status of the skin, and are influenced by medication and by the way the test is performed. There is a small but definite risk of systemic reactions induced by skin tests (7).
Another difference is the standardization. SPT results depend on the quality of the extract, the skill of the person performing the test, the location of the skin test site, and on medical treatment. To achieve good standardization, all these parameters must be well controlled, which is not easy. In contrast, ImmunoCAP IgE determinations are standardized by the test manufacturer and the testing laboratory is assessed by means of international or national quality assessment programs such as NEQAS in the UK. This ensures excellent standardization.
At what age can you start taking an allergy blood test?
Adults and children of any age can take an allergy blood test. For babies and very young children, a single needle stick for allergy blood testing is often more gentle than several skin tests.
References
- Allen-Ramey F, Schoenwetter WF, Weiss TW, Westerman D, Majid N, Markson LE. Sensitization to common allergens in adults with asthma. J Am Board Fam Pract. 2005;18:434-439.
- Milgrom H. Understanding allergic asthma [news release]. Milwaukee, WI: American Academy of Allergy, Asthma & Immunology; June18, 2003.
- Høst A, Halken S. The role of allergy in childhood asthma. Allergy. 2000;55:600-608.
- NIH. Guidelines for the Diagnosis and Management of Asthma, 2007. NIH publication 08-4051.
- Niemeier NR, de Monchy JG. Age-dependency of sensitization to aero-allergens in asthmatics. Allergy 1992;47:431-5.
- Daniel Vervloet, Michel Pradal. Drug Allergy. Sundbyberg: S-M Ewert AB, 1992:4, 55.
- Nelson HS. Variables in allergy skin testing. Allergy Proc 1994;15(6):265-8