Currently, more than half of the North American population suffers with at least one type of allergy, and the numbers are on the rise. Allergic reactions to foods and environmental aggravators can result in a variety of bothersome symptoms, including: nasal congestion, asthmatic attacks, coughing, wheezing, shortness of breath, headaches, fatigue, hives and other types of skin rash, puffy eyes and anaphylactic episodes.
Almost any substance can provoke allergic reactions, and identifying personal allergens is vital, in order to keep symptoms under control and prevent further damage to your health. Unfortunately, the two most commonly used methods of detecting allergies are outdated and often yield false results. In fact, two leading allergists– Robert Wood of the Johns Hopkins Children’s Center and Scott Sicherer of Mt. Sinai Hospital in New York, are now advising all Doctors to avoid using these two traditional allergy tests as a stand-alone means of diagnosis.
Skin Prick and Allergy Blood Test Basics
Most allergic reactions are thought to be caused by the activation of immunoglobulin E (IgE) antibodies in response to a substance that the individual’s body has identified as harmful.
The skin prick test involves pricking the skin with minute amounts of an allergen and noting how the skin reacts. If a hive-like wheal at the injection site appears, it shows that the individual’s immune system has created IgE antibodies in response to that substance, and it is supposedly indicative of an allergy. Allergy blood tests, on the other hand, involve withdrawing blood and measuring the levels of specific IgE antibodies that are circulating within it. There are many problems with these two types of tests however.
Why These Tests are Futile
According to Wood and Sicherer in the January 2012 issue of Pediatrics Journal, the activation of IgE antibodies merely indicates sensitivity to that substance; it does not necessarily mean that there is an actual allergy to it. In fact, many patients who test positive to substances during the skin prick or blood test do not actually demonstrate any allergic reactions when exposed to the allergen outside of the clinic. According to past research, false positives are so common that up to 8% of children test positive for peanut allergies when given the skin prick or blood test, and yet only 1% of them demonstrate any clinical symptoms.
Another problem with these tests is that they have no way of foretelling what type of allergic reactions a person will experience, nor do they reveal how severe the allergy actually is, which could leave a severely allergic individual extremely vulnerable to extreme or even fatal allergic reactions. In addition, skin prick and blood tests are unable to detect antibodies to medications and are therefore useless when it comes to the detection of drug allergies. Additionally, certain medications, such as tricyclic antidepressants as well as corticosteroids, can prevent an IgE reaction from occurring and an individual’s allergy may remain undetected when given these two tests. Furthermore, commercial tests vary in sensitivity and different laboratories may interpret test results in different ways, possibly yielding very dissimilar results.
Finally, food sensitivities and food allergies are becoming increasingly common in North America, and the blood test and skin prick test are particularly ineffective at detecting them. According to allergy specialist L. DuBuske, the accuracy of skin food tests in predicting food allergies can be as low as 50%. Moreover, when it comes to food sensitivities, the blood test and prick test are pretty much useless because food sensitivities do not provoke an IgE response. Instead, consuming a food that you are sensitive to causes your immune system to create an overabundance of IgG antibodies and the blood test and skin prick test do not measure IgG levels.
As mentioned earlier, it is extremely important that allergies are accurately diagnosed. Continuous exposure to an unidentified allergen, can not only wear out and damage your immune system, it can also damage your overall health and diminish your vitality. Unfortunately, when it comes to detecting environmental allergies, there aren’t currently any tests which yield more reliable results. However, when it comes to food allergies, you should talk to your doctor about undergoing a food challenge, which is considered the gold standard for diagnosis. Finally, if you suspect that you have food sensitivities, talk to your healthcare practitioner about having an ELISA test done, or consider following an elimination diet; both of which can help you to identify the offending foods.