Test for allergy

In order to get rid of allergies, you need diagnostic accuracy, that is, the identification of a specific allergen or a group of allergic provocateurs. The allergy test is a specific diagnostic method that is applied after the information about possible allergens and the general anamnesis have been collected.

The allergy test can be performed in a variety of ways, depending on the suspected antigen group, the patient's age and health status. Allergic tests can be dermal, which in turn are divided into quantitative and qualitative, direct and indirect, and testing is conducted in a provocative way. The principle of carrying out the tests is simple: the putative stimulus is introduced into the patient's body in various ways, after which all the nuances of the allergic reaction are evaluated. All tests are performed during remission, 2.5-3 weeks after the last exacerbation.

How dangerous is the allergy test?

Like any method of diagnosis, tests are conducted only in special laboratories under the supervision of specialists. Of course, an allergic reaction can not only be, but more often than not, it is inevitable, in fact the tests are directed at its provocation. However, to be afraid of complications or other troubles it is not necessary, as all procedures assume a minimum introduction of an allergen, besides, there are always both doctors and medicines nearby.

The allergy test is one of the important components of a comprehensive allergy test. It should be borne in mind that virtually all types of samples require a therapeutic "window" in 7-10 days, since taking antihistamines, corticosteroids or sedatives can distort the diagnostic picture of allergic tests.

What antigens help determine an allergy test?

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

1. Nutritional - this is a huge list of products, which includes almost all food components. Most often, a food allergy develops on 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 inclusion in the process of the immune system. 
2. Contact - this is most often chemicals that provoke allergies in direct contact with skin. 
3. Infectious - bacteria, parasites, viruses, and other microorganisms that cause a major inflammatory disease, and then an allergy. 
4. Inhalation - animal hair, pollen of flowers, plants, trees.

Classification and types of tests for allergy

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

• Qualitative skin test for allergy: Qualitative method allows to identify the presence of sensitivity to the drug being administered.

Direct test, when the antigen is administered externally by a drip or application method, as well as using a scarifier (scratch) or a needle (prick). The reaction is considered positive if blisters, redness, or slight puffiness form on the skin. The reaction should appear after 15-20 minutes, but it can develop and a little later - in a few hours and even a day.

• An indirect test for allergy is carried out by subcutaneous injection of blood serum allergy, and then the actual allergen. This method is rather complicated, since it requires the correspondence of not only the blood group of the subject and the blood of the allergic person, but also the constant monitoring of the patient for several days.
• Skin quantitative test for allergy allows you to clarify the degree of sensitivity to the allergen. Such a method in allergology is called allergometry or titration. When carrying out a quantitative test, the lowest dose of the allergen is detected, to which the patient's body is sensitive.

A provocative allergy test is needed to clarify the diagnosis, when skin tests give conflicting information that does not coincide with anamnestic data. Allergens are injected into the patient's organ or tissue, more precisely, into the zone that most reacts to the alleged provocative substance. Among the provocative tests the following are the most common: 

• Conjunctival or ophthalmic allergy test when an allergic substance is buried in the lower bag of the conjunctiva. The reaction, which should appear after 15-20 minutes, looks like an increased tear, redness, it feels like a strong itch. •
• Nasal or nasal allergy test, which is effective in the sense of determining the causative agent of pollinosis, allergic rhinitis. The control liquid by a dropwise route is introduced into one nostril, the antigen is introduced into the other. With a positive reaction to the allergen, there are signs of shortness of breath, shortness of breath and itching in the nostril. 
• Cold or heat test for allergy, helps to clarify subspecies quite rare allergy - cold, thermal, which is also called thermal urticaria. 
• Inhalation test for allergy is very effective in diagnosing bronchial asthma of allergic etiology. During the test, the patient is allowed to inhale the aerosol form of the allergen, and the lung volume is evaluated. If it decreases by 15 percent or more, the reaction to the allergen is considered positive. 
• Elimination test, which is considered one of the easiest among the diagnostic tests. From the menu of allergy sufferers, the "suspicious" products are gradually removed and the patient's health is monitored, as well as the presence or absence of an allergic reaction. In addition, you can eliminate household dust, wool and animal dander, but this option assumes stationary conditions. 
• The exposure test for allergy is carried out with idiopathic forms of allergy, that is, those whose cause is not established. The patient is consciously given the opportunity to contact the alleged provocateurs, but unlike the home conditions, allergies are monitored by doctors. 
• A leukocytopenic test, as well as a thrombocytopenic allergy test, is needed to determine the true pathogen from a group of drugs. Also these variants of tests are suitable for revealing the possible cause of false allergy, idiosyncrasy or, more precisely, intolerance of some food products.

[1], [2], [3], [4]