Tests to check for an allergic reaction can help to find out what is the causative agent of asthma symptoms. These tests can help your doctor identify asthma triggers and make the right treatment program that solves breathing problems. If the doctor suspects that any allergen causes an exacerbation of allergic asthma, he will recommend taking a test to check for an allergic reaction.
Tests for allergy and asthma
There are several types of tests for checking for an allergic reaction, including a skin test, a blood test and other diagnostic tests in the laboratory. These tests can determine if you have any other infections or problems. After passing the tests, the doctor will be able to determine what causes asthma and allergies and will be able to prescribe a more effective treatment.
A skin test is quick, relatively reliable, inexpensive and helps determine what triggers an exacerbation of asthma. The test results are usually known within an hour. It is very important to follow all the doctor’s instructions. It is necessary to stop taking the antihistamine before starting the test. The doctor can also report on other measures to prepare for this test.
A skin test is necessary if there are strong suspicions that a particular allergen or a group of allergens causes an exacerbation of asthma and allergies. The skin test is the injection of an injection with a certain allergen under the skin to reveal the response of immunoglobulin E. This substance, which can be found only in the body of people suffering from allergies, activates the mast cell (fat cells) on the skin. Mast cells then produce substances called mediators, such as histamine, causing swelling, redness, and itching. Increased level of immunoglobulin E shows that the body is very sensitive to certain allergens.
Your attending physician may use one of these tests on the skin: an injection skin test, an intradermal test and a scarification (skin allergic) test. (Note: if you have poorly controlled asthma, reduced lung capacity, or a predisposition to anaphylactic reactions to allergens, be sure to tell your doctor. )
Injectable skin test
An injectable skin test is the most common type of allergic test. A few drops of the allergen drip onto the skin, most often on the back. Then each drop is pierced by a needle. After 15 minutes, a rash may appear if your body has immunoglobulin E, which reacts to a certain allergen. Surely the doctor will want to confirm the test results with the history of your illness or hold a new test.
Reaction to a test with a diameter greater than 3 mm is considered positive (ie, the presence of allergies in the body). This small rash can also blush and itch.
The intradermal sample can be used if the result of the injectable skin test is negative. The doctor injects the allergen directly into the skin. The technique is the same as that used in the Mantoux sample to detect tuberculosis. The intradermal test is often used to detect allergies to external factors and/or medications. This type of test is not suitable for determining food allergy or allergy to latex.
Although the intradermal test reveals a greater sensitivity of the body, but at the same time there is a high level of false results. Intradermal tests can cause a systematic allergic reaction and are therefore only used when the injectable skin test does not produce the desired result.
During the scarification test (skin allergic test), a doctor drops a few drops of a certain allergen onto the bandage and places the bandage on the skin. Sometimes this type of test can help determine the pathogen of skin allergy. If the skin reddened, there was irritation and itching, then you are allergic to this allergen.
There are several types of blood tests (including those listed below) that your doctor can suggest if your skin test is not possible. Although the blood test is less sensitive and more expensive than skin tests, a blood test also determines the presence of immunoglobulin E.
Radioallergosorbent test – a blood test, which is used to determine the reaction of immunoglobulin E to certain pathogens. It is carried out in a test tube. Although this test is not as accurate as a skin test, a radioallergosorbent test is recommended for people who are hypersensitive when the skin test is a threat to human health. This test is much more expensive than skin tests, but the medications that you take to treat asthma, can not affect the test results in any way. The test is also recommended for children to rule out an allergy to the respiratory tract.
Radioallergosorbent test on paper
If you have a chronic sinus-pulmonary disease (including rhinitis, sinusitis, bronchitis and non-allergic asthma), the attending physician can recommend a radioallergosorbent test on paper. This test provides an accurate picture of the level of immunoglobulin E in the body. Immunoglobulin E – antibodies found in the mast cells of the skin. An increased number of antibodies indicates the presence of an allergy or infection in the body. Observation of the level of immunoglobulin E helps to monitor the effectiveness of treatment of certain allergic diseases. (The normal level of antibodies to immunoglobulin E does not exclude the diagnosis of allergic diseases.)
Quantitative assay of immunoglobulin E
A quantitative test of immunoglobulin E determines the presence of immunoglobulin or various antibodies in the blood.
Take a blood test to determine the level of immunoglobulin. If the level of immunoglobulin E is high, then you can assume an allergic cause of the symptoms, for example, rhinitis or asthma. If there is a high level of other types of immunoglobulin, then probably in the body there are other infections, for example, pneumonia or fungus. A reduced amount of a specific type of immunoglobulin can signal that the body’s immune system is struggling with certain infections caused by bacteria or viruses.
Allergic injections and asthma symptoms
If medications are not effective in treating allergy and asthma symptoms, the doctor may prescribe allergic injections (immunotherapy). Injections are quite effective in reducing allergic symptoms associated with reaction to pet hair, pollen, house dust mites, mold and red ants bites. A regular injection of an allergen into the body in an ever-increasing dose stimulates changes in the immune system, which leads to a decrease in the allergic reaction in the future.