Living with allergies can turn your world upside down. Whether you’re dealing with chronic sinus problems from environmental allergies or you live with all the issues that can come from food allergies, Asthma Allergy Center, located in Tigard, OR, is here to help. By utilizing allergy testing, we are able to effectively identify and treat your allergies so you can get back to living your life.
How Does Allergy Testing Work?
If you’ve been dealing with allergies for a while, you might already know what you are allergic to. However, this isn’t the case for everyone. Determining what you are allergic to is the first step in treating your allergies. Our office uses the skin prick test and food challenge test to help figure out exactly what substances are causing your allergies.
Skin Prick Test
The prick through the drop test, or skin prick test, are used to check for immediate allergic reactions. One reason they are so helpful is that your doctor can test as many as 50 different substances at once to check your reaction. This test is most often used to identify allergies to pollen, mold, pet dander, dust mites, and food. For adults, the test is usually done on the forearm, while children might be tested on the upper back.
First, the area of your skin that is being tested will be cleaned with alcohol. Then, the nurse will draw small marks on your skin to indicate where each drop of an allergen will be placed. Next, the nurse will put a drop of allergen extract next to each mark. Then, they will use a small lancet to prick the extracts into the skin’s surface. A new lancet is used for each allergen to ensure that there is no cross-contamination.
It’s important to note that this process isn’t painful – the lancets being used are so minuscule that you should barely be able to feel them.
In addition to allergens, the nurse will introduce two additional control substances to your skin to ensure that your body is reacting normally: histamine and saline. In most people, histamines cause an allergic reaction. That’s why anti-allergy medications are often called anti-histamines. If you don’t react to the pure histamine, your skin prick test might not reveal an allergy, even if you have one. This is called a false negative.
On the other hand, most people do not react to saline. If you do have a reaction to the saline, it may mean that you have very sensitive skin, and the test results will need to be interpreted with caution to ensure that you do not receive a false allergy diagnosis, also known as a false positive.
Interpreting the Results
After the nurse is done pricking all the allergens and control substances, you will wait for about 15 minutes to give your body time to react. The nurse will examine your skin for any signs of allergic reactions. If you are allergic to any of the substances that are being tested, you will notice that you have developed a raised, red bump that looks like a mosquito bite.
This bump is usually itchy. The nurse will measure it and record the results. Last, the nurse will clean your skin to remove the marks. The test sites, along with any wheals that may have developed, usually only take up to 12 hours to disappear, but can disappear instantly. If you had a relatively intense allergic reaction to one of the substances, it may take two or three days. If the bumps feel uncomfortable or itchy, you can take an antihistamine to help reduce the symptoms.
Medications That Can Interfere With Results
Before having a skin prick test, let your doctor know about any prescription or over-the-counter medications that you take. Some medications suppress allergic reactions and therefore can taint the results of your skin prick test. Medications clear out of your system at different rates, so your doctor will ask that you stop taking certain medications for up to 10 days before your test, while others you can continue taking until a few days before.
Some common medications your doctor will ask you to stop taking prior to your test are prescription and over-the-counter antihistamines, as well as tricyclic antidepressants. Certain heartburn medications, such as cimetidine and ranitidine, can also impact your test results, as can the asthma medication Xolair.
Food Challenge Tests
Food Challenge tests are used to identify food allergies. This highly accurate test can cause a serious allergic reaction, which is why it is done in the office. Generally, oral food challenge tests are done to confirm a suspected allergy to specific foods.
During this test, your doctor will feed you measured doses of the food being tested. They will start with very small amounts that are not likely to trigger a reaction. After each small dose of the suspect food, your doctor will observe you for a period of time for any allergic reaction. Assuming you have no symptoms, your doctor will gradually give you larger doses. The test stops as soon as signs of an allergic reaction are present.
The most common symptoms to experience during a food challenge test are mild, like developing some hives or becoming flushed. It’s uncommon to experience severe reactions because your doctor is feeding you very small, measured doses. If you develop symptoms that are uncomfortable, your doctor will give you medication to relieve your symptoms.
Allergic Reactions During the Food Challenge Test
If you do not develop any allergic reaction by the end of the food challenge test, the food will be ruled out as a possible allergy. On the other hand, if the test confirms that you do have an allergy, your doctor will discuss with you how to avoid this food. They may also prescribe medications to manage your allergy. Sometimes, a food challenge test is used to test an allergy that you already know you have. These tests are useful to determine if you have grown out of an allergy.
During food challenge tests, your doctor may give you either a test food or a control food. A test food is a food that you and your doctor believe you may be allergic to and are testing your reaction to. A control food, or placebo, on the other hand, is one that you and your doctor know you are not allergic to. Using a control allows your doctor to observe your normal reaction to foods you tolerate so that they can later compare it to your reaction to test foods.
Types of Food Challenge Tests
Having any sort of medical testing can be anxiety-provoking. This is especially true when the medical test includes the purposeful invoking of an allergic reaction. Symptoms of an allergic reaction and symptoms of anxiety can have some overlap, and anxiety can also work to exacerbate allergy symptoms. Because of this, doctors have created three different types of food challenges to help control reactions.
Open Food Challenge
In this kind of food challenge, both you and your doctor know whether or not you are receiving an allergen. This test is most likely to be used when your anxiety is unlikely to affect the results.
During the open food challenge, you will be given pre-measured doses of the allergen, or test food, and observed for a period of time. The doses will gradually increase in size over the course of an hour. After you have taken all the doses, you will be observed for another three hours to see if you have an allergic reaction.
Single-Blind Food Challenge
This version of the food challenge is called single-blind because while your doctor knows whether you are being fed a test food or a control food, you do not. The placebo and test food will either be given on separate days or hours apart. This allows the doctor to observe your reaction to both the placebo and possible allergen without any anxiety clouding the results.
You might think that you would be able to determine whether you are being given the placebo or allergen by what you’re eating, but that actually isn’t the case. For example, if your doctor is testing a milk allergy, you may be given a piece of a hamburger with milk powder on it. Then, for control, your doctor will give you a piece of a hamburger without milk powder. You won’t be able to visually determine or taste a difference between the two foods.
Double-Blind Food Challenge
When it comes to any scientific testing, double-blind tests are considered the “gold standard.” In a single-blind study, you are not aware of whether you are being given a placebo or an allergen. While your doctor will not tell you during the study which you are being given, it’s possible that they may engage in body language that indicates to you whether or not you are given the allergen.
In a double-blind study, however, your doctor is also unaware as to whether the food you are being given is the placebo or the allergen. This method helps to ensure that neither your doctor’s preconceptions nor your anxiety can affect the outcome of the test.
What Happens Next?
After allergy testing, what happens next? How do you get better? It depends on the types of allergy problems you’re having.
The best way to treat environmental allergies, such as allergies to pollen, animals, and dust mites, is with allergy injections. This treatment is also known as allergen immunotherapy and involves receiving shots on a monthly basis for at least three years.
This is an effective way to “turn off” your allergies by building up your immunity. As you build an immunity to the substances to which you have an allergic reaction, your reaction will begin to lessen in severity until it no longer exists.
If you’re hesitant to get shots, don’t worry! We also offer allergy desensitization with sublingual liquid extracts. It works in the same way as allergy injections, but rather than dealing with needles, you simply put liquid beneath the tongue. Sublingual extracts also offer the added benefit of being able to treat yourself at home. Lastly, sublingual tablets are a once-a-day treatment you can take for grass allergies.
Oral immunotherapy is the most effective method of food allergy desensitization. At first, you will receive micro-doses of the allergen. Your doctor will monitor your gradual increasing of the dose until a much higher dose is tolerated.
Get Rid of Allergy Suffering
Living with allergies is overwhelming. Whether you’re dealing with anxiety or sickness from food allergens, or environmental allergens are giving you sinus problems, there is another option. You can live at peace, without the constant worry and debilitating symptoms. Allergy testing is only the first step.
To schedule a consultation for allergy testing, or to have any questions answered, give us a call at Asthma Allergy Center, in Tigard, OR.