Specialists in Allergy Testing
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Information About the Field of Allergy Testing
What is an Allergy?
Every allergy is always an expression of an imbalance or a disorder of the human immune system. They are hypersensitivity reactions triggered by actually harmless substances. In the case of an allergy, the person cannot develop tolerance to the allergy-triggering substances. Instead, the immune system feels attacked and forms defense substances such as antibodies, inflammatory mediators, or other cell groups.
The substances that trigger allergies are called allergens. According to statistics from the German Society for Allergology and Clinical Immunology, nearly 20 million Germans currently suffer from some form of allergy. However, only about half of them are aware of their condition.
The constantly growing number of allergy sufferers shows how the immunological tolerance capacity of industrialized nations is declining, but it also highlights the irresponsible lifestyle of Western countries. An allergy diagnosis is always helpful and can best contribute to successful therapy.
The fundamental problem in the diagnosis of allergic diseases is to think the allergy has a certain pattern because there are more than 20.000 potential allergens, from which the causative one for the patient has to be found. To do so, complex diagnostic procedures are used, which can be applied according to a four-step allergy diagnostic principle.
Allergy Tests: Which Tests Are Used for Allergy Diagnostics?
Stage I of Allergy Diagnostics: The Patient's Medical History
Valuable information about a potential allergen can already be obtained by taking the medical history for allergies. Lifestyle habits, the professional and private environment, and the psychosocial environment and diet can be used as an approximate orientation of social status.
Particularly important are also self-observed relationships between potential allergens and allergic symptoms and the environmental conditions at the private and professional levels. The onset of the disease and possible initial signals that arose from contact with the potential allergen are also significant.
Stage II of the Allergy Diagnostics: The Allergy Tests of the Skin
Skin tests form the framework of any allergy diagnosis (scratch, rub, prick, or intracutaneous). During these tests, the dermatologist applies specific substances suspected of causing an allergy to the skin and observes the skin reactions, for example, if wheals or pustules develop.
In this way, depending on the diagnostic test, the specialist can narrow down his search and, for example, test for suspicious allergens based on the patient's medical history and disprove or confirm their diagnosis (a confirmation test). In most cases, however, these are not confirmatory tests but search diagnostics. The specialist uses various group extracts to cover a broad allergenic spectrum, preferably in a single session. Skin tests provide more precise results.
- The prick test: A test solution is applied to the arm. Then this spot is pierced one millimeter deep with a prick lancet. A wheal should have developed after about 20 minutes if the test is positive. The prick test is today's standard method for allergies of the immediate type.
- Intradermal test: As the name implies, the potential allergen is injected directly into the skin with the help of a needle. The test is, therefore, almost 10,000 times more accurate than the prick test, but due to this fact, it also delivers false-positive results more frequently, which often occur with food allergens.
- Scratch test: The test solution is applied to the skin and lightly scratched. However, since the skin is irritated by the scratching, this test provides only limited good results and has fallen into the background of many dermatologists today.
- Rubbing test: The test solution is rubbed repeatedly on the patient's forearm. This test is used when the patient has a very high sensitization. Since this test uses a natural allergen, it is possible to use it even if the substance causing the allergy is not present in an industrially prepared form.
- Epi-cutaneous test: This test is also called a patch test. In this test, the specialist applies a patch containing a potential allergen to a part of the body, preferably the patient's back, and observes the skin reaction after about 1-3 days. The epi-cutaneous test is very commonly used to detect type IV allergens.
Stage III - The Laboratory Results
Blood samples are taken and brought into contact with a possible allergen at this stage. The readiness to react and the sensitization of the blood sample to the allergen are observed. Special attention is paid to the body's immunoglobulin E (IgE). This antibody is produced in the immune complex in response to the potentially allergenic substance that the body recognizes as a foreign object.
In allergic patients, this system reacts hypersensitive, and numerous IgE antibodies are formed. Therefore, these blood tests are mainly used in infants and small children because here, the burden of the tests is the lowest: only one blood sample is needed. On the other hand, there is no great danger for the small patient in case of an exaggerated immune reaction, and the intake of anti-allergic drugs can continue since these do not change the blood picture. At the same time, taking these drugs can very well alter skin tests.
Blood tests are also excellent because the dermatologist can usually predict the direction in which the patient's allergy is heading based on the blood test alone and initiate prophylactic countermeasures accordingly.
Stage IV - Evaluation of the Tests and Follow-up Medical History
In the last procedure, the tests and laboratory values are analyzed again. This is because the specialist also wants to determine if the patient has been exposed to the potential allergen and if the patient's symptoms match the test results. Finally, the specialist can only determine if the positive skin tests or the IgE antibodies determined by blood values do justice to their clinical expression of the allergen with a provocation test. The provocation test is on the organ in question and can provide clarity.
A provocation test is an imitation of the allergic symptoms - for example, allergic asthma, rhinitis, allergic conjunctivitis, eczema, and skin rashes - by administering the natural allergens.
What Should Be Considered Before Carrying Out an Allergy Test?
An allergy test will give false results if anti-inflammatory drugs such as antihistamines or cortisone are taken. Therefore, these preparations should not be taken for at least five days before the test.
Which Doctor Carries Out Allergy Tests?
Allergists carry out allergy tests. Allergology is a further qualification that dermatologists, lung specialists, ENT specialists, internists, or pediatricians can complete to call themselves specialists in allergology. These are the appropriate doctors to contact for allergy testing and assessment.
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