Many people experience allergies caused by an inappropriate reaction of the immune system, for example, to plant pollen in the spring or animal hair and any food products. But how to find out what you are allergic to, and what are the common provocateurs.
Pravda.Ru told about it manager CDL Laboratory and diagnostic complex NAKFF Vera Barinova.
Why does an allergy occur?
The immune system of people suffering from allergies sees an aggressor in a foreign substance (allergen) and begins to fight it, producing specific antibodies of the type immunoglobulin E. These antibodies activate the cells of the immune system and induce them to secrete various biologically active substances – histamine, leukotrienes and cytokines, that cause an allergic reaction. Type E antibodies are unique to various specific allergens, so some people may be allergic to weed pollen, while others may be allergic to cat dander, nuts, or paint.
Seasonal allergies, or pollinosis, or hay fever, differ in that it manifests itself at a certain time of the year – in the spring-summer season, when many plants bloom and pollen flies in the air and enters the body through the nose and mouth. Since seasonal allergies are respiratory diseases, the allergic reaction occurs due to the contact of pollen with the respiratory system, therefore, are most susceptible to its influence.
- nose (rhinitis),
- sinuses and airways (asthma),
- as well as the eyes (conjunctivitis).
Therefore, this time of year is especially difficult for people who are allergic to spring flowering. Between periods of exacerbation, there are “periods of silence.”
The first place among allergenic trees is occupied by birch, followed by
The fact that poplar is one of the most allergenic trees is a well-known misconception. Its fluff, collecting pollen from flowering trees and grasses, is a good means for its transportation through the air. Thus, there is a mechanical transfer of allergenic pollen.
How to identify an allergen: diagnostic methods
Special scarification skin tests
The proportion of people with respiratory allergies is about 30% of the population. Seasonal allergies can develop at any age, but symptoms usually first appear during childhood and adolescence, between the ages of 4 and 15.
The diagnosis of seasonal allergies is made by an allergist based on
- questioning the patient
- and carrying out special scarification skin tests.
Their holding is possible only in the “period of silence”, that is, in those months when there is no influence of the alleged allergen – at the end of autumn or in winter.
For this, special solutions are prepared from
- tree and herb pollen extracts,
- house dust mites,
- animal fur,
- fungal mold,
- insect venom,
- and some antibiotics.
A drop of each solution is placed on a person’s skin and the skin is pierced with a needle. If a person is allergic to one or more of these allergens, then he develops a skin reaction of the “bloom” type: within 15-20 minutes, a pale, slightly raised swelling appears at the injection site – a papule, which is surrounded by a clearly defined area of redness – hyperemia. Most allergens can be identified in this proven way.
Method for determination of immunoglobulin E
In some cases, skin tests cannot be performed – for example, with a profuse spread of the rash throughout the body. In such cases, it can be used method for determining immunoglobulin E. However, the accuracy of this method is not very high, since total IgE may also increase in other pathological conditions.
Analysis for specific IgE
For a more accurate diagnosis, analysis for specific IgE, which is an antibody produced by the body against a specific antigen. To detect them, the patient’s blood serum is mixed with the antigen being determined, this allows you to accurately determine the allergy to a particular substance. For diagnosis, mixtures of allergens are primarily used, for example, weed pollen, pollen from early flowering trees, etc., followed by identification of the specific antigen that caused the allergy. The disadvantage of this method is only that it cannot be used in children under the age of six months.
Western blotting method
Enough for now Western blot method is widely used. Immunoblotting (immunoblot) is a highly specific and highly sensitive method for detecting antibodies to individual antigens (allergens), based on the production of enzyme immunoassay on nitrocellulose membranes, on which specific proteins are applied in the form of separate bands.
If there are antibodies against certain allergens, a dark line appears at the corresponding locus. The uniqueness of the immunoblot lies in its high information content, the reliability of the results obtained and the absence of contraindications. Most often, standard panels are used, each of which contains a certain set of allergens.
The “gold standard” in allergy diagnostics is ImmunoCAP technology. Its idea lies in the possibility of detecting ultra-low concentrations of specific IgE antibodies in an ultra-small amount of blood. This is a highly accurate and fully automated IgE antibody test system developed by Phadia. The high sensitivity of the tests is due to the use of a special porous substrate, on which an automatic analyzer can detect even the smallest amount of IgE.
Clinical hospital on Yauza, st. Volochaevskaya, 15
Clinical Diagnostic Center MEDSI on Belorusskaya