What is the mechanism of action of skin tests
These tests involve the examination of a skin reaction (depending on the presence of specific IgE antibodies) - for example after administration of an inhalant allergen extract to the skin. The test is usually carried out in specialist centers.
How to prepare for a skin test?
First, before the test, antihistamines should be discontinued, and earlier, for about 2 weeks, avoid allergy dishes and other sensitizing factors. The condition for skin tests is age above three years of age. The rule that applies to allergy during the test is "health" - no burden of inflammation resulting from allergic urticaria or other allergic disease.
How does contact allergen testing work?
On the unchanged skin is applied paper discs (with dimensions 1x1cm) soaked in an allergen of the right concentration and a control test with a neutral substrate and leave for 48 hours. Then the discs are removed and assessed where the eczema changes occurred. Skin changes induced in this way are in the form of allergic eczema. The degree of intensity of these changes - in the face of a neutral control - should reveal a list of substances that are contact allergens.
Other methods
Testing antibodies in the blood is an accurate diagnostic method. Unfortunately, this method is, but by the way and therefore not available to the public. It allows for precise detection of allergy to individual allergens in a patient of all ages, regardless of the drugs used. Verbal, conjunctival and intrabronchial provocative tests are expensive, labor-intensive and time-consuming. They can be performed only in allergy surgeries to diagnose the cause of allergy.
Eosinophilia in peripheral blood as an asthma test.
In the course of asthma, there is usually an increase in the number of immune cells - eosinophils in the peripheral blood. Eosinophils, or eosinophils, are one of the types of white blood cells distinguished by the presence of large granules in the cytoplasm, colored red with eosin. The study of the number of eosinophils in the blood may be one, but not the only one of the diagnosis parameters, as well as monitoring the effectiveness of treatment. The use of anti-inflammatory agents (glucocorticoids) leads to a reduction in eosinophilia. The number of eosinophils, as well as the concentration of total IgE, may be increased for other disease reasons (eg parasitic infections, haematological diseases). Therefore, it is not a specific test for asthma.
Are the diagnostic methods used sufficient for an error-free diagnosis of an allergen?
The test does not always adequately reflect the body's sensitivity to a given allergen. Ultimately, the final medical history is decisive, showing a relationship between the contact with a particular allergen and the severity of individual symptoms of rhinitis. For example, allergy to dust mites teases most immediately after waking up and clearly intensifies when cleaning the premises with a traditional vacuum cleaner. Therefore, it is best to determine - through a series of detailed questions - the circumstances accompanying the appearance of allergic rhinitis and select suspected allergens, and then confirm this diagnosis with test results.
Ed. Edward Ozga Michalski, MA
Consultation Dr hab. Med. Andrzej Danysz
