Allergy test

In order to get rid of allergies, diagnostic accuracy is necessary, i.e. identifying a specific allergen or group of allergic triggers. An allergy test is a specific diagnostic method that is used after collecting information about possible allergens and a general anamnesis.

An allergy test can be performed in various ways, depending on the suspected group of antigens, the patient's age and health condition. Allergy tests can be skin tests, which in turn are divided into quantitative and qualitative, direct and indirect, and testing is also carried out in a provocative way. The principle of testing is simple: the suspected irritant is introduced into the patient's body in various ways, after which all the nuances of the allergic reaction are assessed. All tests are carried out during the remission period, 2.5-3 weeks after the last exacerbation.

How dangerous is an allergy test?

Like any diagnostic method, tests are carried out only in special laboratories under the supervision of specialists. Of course, an allergic reaction is not only possible, but most often it is inevitable, because the tests are aimed at provoking it. However, there is no need to be afraid of complications or other troubles, since all procedures involve minimal introduction of an allergen, and doctors and medications are always nearby.

An allergy test is one of the important components of a comprehensive examination of an allergy sufferer. It should be taken into account that almost all types of tests require a therapeutic "window" of 7-10 days, since taking antihistamines, corticosteroids or sedatives can distort the diagnostic picture of allergy tests.

What antigens does an allergy test help detect?

Allergenic substances that can trigger an aggressive response from the immune system are divided into the following categories:

1. Food - this is a huge list of products, which includes almost all food components. Most often, food allergies develop to cow's milk protein in children under two years of age, in adults, the reaction to food is most likely caused by a false allergy, that is, intolerance to certain substances without the inclusion of the immune system in the process.
2. Contact substances are most often chemical substances that provoke allergies upon direct contact with the skin.
3. Infectious – bacteria, parasites, viruses, and other microorganisms that cause the underlying inflammatory disease, and then allergies.
4. Inhalation - animal hair, pollen from flowers, plants, trees.

Classification and types of allergy tests

Skin tests that help to more accurately determine sensitivity to an allergen and the intensity of an allergic reaction. A skin allergy test is performed by introducing a small dose of the allergen into the patient's skin.

• Qualitative skin allergy test: The qualitative method allows to detect the presence of sensitivity to the administered drug.

Direct test, when the antigen is applied externally by drop or application, as well as with a scarifier (scratch) or needle (prick). The reaction is considered positive if blisters, redness or slight swelling form on the skin. The reaction should appear after 15-20 minutes, but it can develop a little later - after several hours or even days.

• An indirect allergy test is performed by subcutaneously injecting the allergy sufferer's blood serum and then the allergen itself. This method is quite complicated, as it requires not only the blood group of the person being tested and the allergy sufferer to match, but also constant monitoring of the patient for several days.
• A quantitative skin allergy test allows you to clarify the degree of sensitivity to an allergen. In allergology, this method is called allergometry or titration. When conducting a quantitative test, the smallest dose of an allergen to which the patient's body is sensitive is detected.

A provocative allergy test is needed to clarify the diagnosis when skin tests provide contradictory information that does not coincide with the anamnestic data. Allergens are introduced into the patient's organ or tissue, or more precisely, into the area that reacts most to the suspected provocative substance. The most common types of provocative tests are:

• Conjunctival or eye allergy test, where an allergic substance is dropped into the lower sac of the conjunctiva. The reaction, which should appear after 15-20 minutes, looks like increased lacrimation, redness, and feels like severe itching. •
• A nasal or nose allergy test that is effective in terms of identifying the causative agent of hay fever, allergic rhinitis. The control liquid is dripped into one nostril, the antigen is introduced into the other. With a positive reaction to the allergen, signs of shortness of breath, difficulty breathing and itching in the nostril appear.
• A cold or heat allergy test helps to clarify the subtypes of a rather rare allergy – cold, heat, which are also called temperature urticaria.
• An inhalation allergy test is very effective in diagnosing bronchial asthma of allergic etiology. During the test, the patient is given an aerosol form of the allergen to inhale, and the lung volume is assessed. If it decreases by 15 percent or more, the reaction to the allergen is considered positive.
• Elimination test, which is considered one of the simplest diagnostic tests. "Suspicious" products are gradually removed from the allergy sufferer's menu and the patient's health condition, as well as the presence or absence of an allergic reaction, are monitored. In addition, household dust, hair and animal dander can be eliminated, but this option requires stationary conditions.
• An exposure test for allergies is performed for idiopathic forms of allergy, i.e. those whose cause has not been established. The patient is consciously given the opportunity to contact the suspected provocateurs, but unlike at home, the allergy sufferer is monitored by doctors.
• The leukocytopenic test, as well as the thrombocytopenic allergy test, are needed to determine the true causative agent of the reaction from a group of drugs. These test options are also suitable for identifying the possible cause of a false allergy, idiosyncrasy, or, more precisely, intolerance to certain foods.

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