Preparing for an allergy test. What are skin tests for allergies in adults and where to do them? Indications for the appointment of the study

The term "allergy tests" or "allergy tests" refers to 4 types of tests:

• skin test,
• blood test to determine the total level of immunoglobulin E,
• blood test for the determination of specific antibodies,
• provocative tests.

Results from one or two of these tests are required to make an accurate diagnosis. The examination begins with skin tests. In the presence of contraindications, they resort to a safer diagnostic method - a blood test for antibodies. A provocative allergen test is used only in extreme cases: if there are discrepancies between the results of studies already conducted and the patient's medical history (for example, a survey shows that the patient is allergic to birch pollen, but skin tests do not confirm this).

Allergies to various substances most often manifest the same symptoms. It is difficult to determine the cause of an allergy without resorting to special skin tests, more commonly called allergy skin tests. This method is the most common in allergology, and is used to establish an accurate diagnosis.

Allergy tests are carried out for diseases such as:

• bronchial asthma, manifested by recurring signs of suffocation as a result of bronchial spasm when exposed to allergens;
• allergic dermatitis, characterized by rashes, redness and itching;
• hay fever or pollen allergy, which is manifested by rhinitis, conjunctivitis, sneezing and runny nose;
• food allergy, which is characterized by skin rashes, redness and itching.

How are skin tests done?

Skin tests for allergens are scarification, with skin piercing (prick tests) and intradermal. In the first two cases, the procedure is quite simple. On the skin of the patient's back or forearm, the doctor applies solutions of "interested" allergens - no more than 15-20 per procedure. Under the drops, using a special plate, scratches are made (scarification method) or shallow injections with a thin needle (prik method). It doesn’t take long to languish in ignorance - the doctor evaluates the results of the samples in 20 minutes.

Skin allergy tests are not carried out:

• during an exacerbation of any chronic disease (including allergies),
• during acute infectious diseases,
• children under 3 years old,
• pregnant and lactating women.

In addition, it is not recommended to resort to this research method for women in the first days of the menstrual cycle. Due to hormonal changes occurring in the body, test results may be unreliable. In order to take an allergy test, the patient is asked to prepare in advance:

2 weeks before the procedure, stop taking internal antihistamines,

stop using anti-allergic ointments for a week.

Animal allergens: animal dander, mixture (total result): cats, horses, golden hamster, dogs

Individual allergens (1 allergen)

Animal food panel (individual result): lamb, beef, turkey, shrimp, chicken, salmon, cow's milk, goat's milk, egg white, egg yolk, pork, cheddar cheese, cod, tuna, hake

The sensitivity of the body to certain aggressive substances is established by conducting allergy tests. This is a research method in which an allergen is applied to the skin or mucous membranes, after which the reaction to it is studied. It is usually prescribed in case of frequent, in the presence of a rash, and also before using anesthesia.

General information

Allergy tests, or allergy tests, are considered the most accurate method for diagnosing sensitization of the body. When they are performed, they take standardized allergens that have been approved for use. Getting on the skin or under the skin, depending on the method of research, they begin to interact with special cells that ensure their transportation to mast cells.

If, after this, the release of allergy mediators and the development of a local allergic reaction in the form of a rash, redness occurs, the injected chemical is recognized as an allergen.

Before the appointment of allergy tests, a complete examination of the body is performed. Due to the fact that this method of research is associated with the risk of developing severe allergic reactions, it should be carried out in the office of a specialist under his supervision.

Indications for allergy testing

Allergy tests are carried out for both adults and children in case of:

• development, manifested by regular attacks of suffocation due to bronchospasm provoked by allergens;
• accompanied by redness of the skin, rash, itching;
• , expressed by sneezing when inhaling pollen;
• drug allergy, manifested by a rash, itching of the skin and mucous membranes;
• - most often accompanied by skin rashes, although it is also possible - indigestion with the occurrence of discomfort and pain in the stomach.

Complaints of the patient, in which the doctor can write out a referral for allergy tests:

• causeless, runny nose, manifested repeatedly;
• itchy eyes or nose;
• a rash on the body that causes itching and does not go away for a long time;
• swelling of the mucous membranes or skin;
• shortness of breath, causeless attacks of suffocation, wheezing;
• redness and swelling of the skin, rash, difficulty breathing due to an insect bite;
• dry skin.

Such analyzes are primarily carried out in order to identify and exclude an allergen that undermines the immune system and worsens the quality of human life. In addition, they can be used to test new cosmetic products, as well as household chemicals.

Types of allergy tests

There are several types of tests to detect allergies. The choice of each of them is carried out by the doctor based on the patient's complaints.

Most often, the doctor prefers:

• immunological;
• skin allergy tests.

Due to the fact that skin tests do not give a 100% result, the allergist usually prescribes a blood test. In this case, antibodies to allergens are detected, which allow diagnosing an allergic reaction.

It is worth noting that blood tests are especially important if the allergy develops rapidly, within an hour. Then each new contact with the allergen can provoke the development of more severe consequences for the body.

note

There is also the concept of provocative tests. These are tests in which substances are applied directly to the conjunctiva or to the mucous membranes of the nasal cavity, for example, at the time of inhalation, and thereby provoke redness, itching, nasal congestion, and sneezing.

Such a diagnosis allows you to determine the presence of an allergic reaction at its first manifestations.

It implies the use of the following methods:

• tests for total immunoglobulin E;
• tests for specific immunoglobulins;
• tests for ImmunoCap.

The essence of such studies is to detect immunoglobulins E and G in the blood - these are antibodies that are formed in response to allergens entering the body.

Total IgE test

It is prescribed for children and adults when they have:

The total IgE test is performed by drawing blood from a vein. Before it, in the morning you can not eat or drink. Any medications taken during this period should be reported to the doctor in advance.

Preparation for diagnostics includes:

• refusal of alcohol, fatty and spicy, as well as products that can cause allergies (chocolate, citrus fruits, egg white) a few days before the date of the event;
• emotional and physical calmness 3 days before the analysis (physical activity, stress are not recommended);
• Stop smoking 60 minutes before the test.

Norms:

Tests for specific IgE and IgG4

Such methods are used when the clinical picture does not allow to determine which allergen provokes the development of an allergic reaction. They are also prescribed for common dermatitis.

The essence of the tests is to mix blood serum with allergens - pollen, animal saliva, dust, cosmetics. Additionally, enzymes and radioisotopes are used. If the rules of the procedure described in the previous subsection are observed, the specialist receives accurate results.

note

The main advantage of the test for specific immunoglobulins IgE and IgG4 is that it does not require the patient to come into contact with allergens. Thus, a safe and informative study is carried out.

In this case, the doctor may recommend a specific allergopanel(food, fungal, panel of alcohol allergens) depending on the anamnesis. Each of these panels includes 20 to 100 allergens to which sensitivity is being studied. If necessary, an in-depth allergy screening is performed, when the specialist selects several substances, one by one, for the test.

In time, such diagnostics can stretch for several days, depending on the work of the laboratory.

Norms:

Tests for ImmunoCap

They are carried out in cases where conventional diagnostics do not allow establishing accurate results. Their advantages lie in the ability to identify an intolerant substance, as well as cross-reaction between molecules of different types and determine the most powerful allergen.

Preparation for conducting such an analysis is no different from preparing for previous tests. However, due to the fact that a larger volume of blood is needed for the study, it is not prescribed for young children.

The procedure can take up to 3 days. It allows you to identify allergies to pollen, food, mites, fungi, plants, dust.

Skin allergy tests

During skin allergy tests, allergens are applied to the skin, after which the specialist observes its reaction. No more than 15 - 20 samples can be used at a time. Moreover, it is permissible to conduct an analysis for children and adults aged from 3 to 60 years.

note

At the age of 5, it is permissible to conduct a test with only two solutions of allergens.

According to the type of skin allergy tests, there are:

Allergens are applied to the area of ​​​​the forearms (where the arm is bent), rarely - to the back. It is recommended to have a snack before the procedure. Also, the doctor must be warned about all the medications that are currently being taken. A week before the analysis, it is worth stopping taking, and 2 weeks before, glucocorticosteroids.

There are several ways to perform quality allergy tests.:

Regardless of the method of performing allergy tests, all tests are carried out in a specialized institution, where, if necessary, the patient can be provided with qualified medical care.

The methodology for conducting high-quality allergy tests includes the following steps:

• Treatment of the skin with alcohol.
• Labeling to distinguish between different allergens.
• Directly performing the test - applying a drop of an aggressive substance or applying a tissue with it. In the case of choosing a scarification test, scratches up to 5 mm long or small skin punctures (up to 1 mm) are made.
• Monitoring the condition of the skin and the well-being of the patient.
• Evaluation of results - the stage can stretch for a period of 20 minutes to 48 hours.

The result of the analysis depends on the rate of occurrence of redness or blisters on the skin.

Additionally, the “-” and “+” marks reflect the degree of sensitivity to an aggressive substance. At the end of the procedure, the patient is advised to stay within the walls of the medical facility for another hour.

Causes of false results

False positive or false negative test results occur if:

• the analysis methodology is violated - for example, when scratches are made incorrectly (too close to each other - at a distance of less than 20 mm);
• the rate of manifestation of an allergic reaction decreases due to the use of antihistamines;
• the rules for storing allergen preparations are violated;
• the specialist applies / injects too low a concentration of the substance.

Provocative Tests

In medical practice, there are cases when the usual allergy tests do not reveal an allergic reaction, meanwhile, its signs are present. Then the doctor decides to conduct provocative tests. The principle of their action is reduced to the introduction of the allergen precisely in the area in which the allergic reaction manifests itself most clearly.

Before analyzing the issue of allergy tests, we will find out what an allergy is. An allergy is essentially an over-sensitivity to a substance. This disease has a lot of unpleasant symptoms (itching, sneezing, runny nose, rash), in addition, it can be fatal. Therefore, if you have allergies, you need to pass special tests as soon as possible.

When should you get tested for allergies?

An allergist is involved in the treatment of this disease. It will help you decide which analysis you need to pass in order to find out exactly what substance an individual reaction exists to. Allergies can be caused by many substances. It is difficult, and sometimes unsafe, to track the reaction of the human body to certain foods or drugs on your own.

To understand this issue in more detail, we list the main symptoms of allergies:

• itching, burning (read also -);
• sneezing, runny nose;
• rash, rashes;
• irritation;
• skin redness;
• peeling;
• edema, including Quincke's edema;
• rarely - shortness of breath.

If you have these symptoms, you should seek the help of a specialist. Now let's find out what types of tests for allergies are. They are needed in order to accurately prescribe the method of treatment.

Types of allergy tests

Types of allergy diagnostics are divided into:

• Blood analysis. It is widely used for various types of allergies. Its task is to establish the presence of antibodies to allergens in the blood and the level of immunoglobulin E. Using this method, the general group of allergens is first determined, in order to then establish a narrow group. The results are deciphered by a doctor; not only the level of indicators is important, but also their ratio.
• Skin tests. The advantages of this method are ease of implementation and fast results. Skin tests are performed by injection or scratching under the skin with the introduction of a small amount of allergens. The procedure is absolutely safe, the minimum amount of a substance is injected under the skin, which can only cause a local reaction. The result is ready in 40 minutes. If there is an allergy to the injected substance, the skin will turn red, slightly swollen, and a rash will appear.

• scarification test;
• prick test;
• subcutaneous;
• application.

Additional Information. Which type to apply in a particular case is determined by the specialist depending on the individual characteristics, age and severity of symptoms.

• nasal - used for. To do this, a potential allergen is injected into the nose, and the reaction is monitored (sneezing, itching, runny nose, swelling);
• conjunctival - used to determine allergic conjunctivitis. A solution with an allergen is instilled into the eyes, after which the reaction of the body is observed (lacrimation, itching, redness);
• inhalation - used to detect bronchial asthma. Such a test is carried out only in a hospital setting. To conduct it, the patient is inhaled with a solution of potential allergens and their breathing is monitored.
• sublingual - used to detect allergies to food, drugs. To do this, a special material impregnated with an allergen solution is placed under the tongue, and the reaction of the body is monitored.

Allergy prick test (video)

Preparing for allergy testing

We list the basic rules for preparing for the delivery of tests for allergies.

• For 3-4 days, you should stop taking all medications, including antihistamines. If the drugs are on the list of vital ones, or the refusal of antihistamines will cause a serious condition, then this issue is decided by the attending physician.
• Do not eat citrus fruits, nuts, honey, seafood, berries, exotic foods, eggs, milk, foods with a high content of dyes, flavors.
• Do not drink alcohol 2-3 days before the test.
• Stop contact with cats, dogs, birds and other animals.
• In the presence of a viral infection with a high temperature, the tests should be rescheduled until recovery.
• Tests should be taken in the morning on an empty stomach. If we are talking about a child, you need at least a 3-hour break from the last meal.
• On the eve, it is desirable to exclude a large physical activity, and how to get enough sleep.

Features of testing for allergies in a child

Note! No more than 5 potential allergens can be tested in one procedure.

Important! There is a contraindication: for children under 3 years old, only a blood test is performed. But sometimes the age limit is increased to 5 years. It depends on the severity of the symptoms.

Consider the most popular allergy tests.

Allergy testing for cats and dogs

Many people think that short-haired animals cannot cause allergies, but this is not the case. The fact is that allergies are caused not only by wool, but also by saliva, urine, feces, particles of exfoliated skin. The analysis is carried out by taking blood or skin samples.

Analysis for food allergies

For adults, from 10 to 300 species can be checked in one procedure. This test is performed by drawing blood from a vein. The results of the analysis are generated as a list of potential allergens with data on IgG antibodies. All foods are reduced to the following scale for evaluating the reaction of the body:

• low - with indicators less than 1000 ng / ml, that is, there is no allergy to this product;
• medium (from 1000 to 5000 ng / ml) - there is a slight allergy to this product, it can be consumed no more than 2 times a week;
• high (more than 5000 ng / mg), there is a strong allergic reaction to the product, it is banned.

Skin tests for allergens are one of the main ways to diagnose allergic diseases. The results obtained after a skin test allow the doctor to develop a treatment plan, and the patient to avoid allergens in the future. In the article, we will consider what an allergy examination is and how an allergy test is done for children and adults.

What are allergy tests?

Allergy tests on the skin are the most well-known diagnostic method for determining substances to which a person has an increased reaction of the body. Their popularity is due to the fact that they are carried out almost painlessly and cover a wide range of allergens, especially those related to airborne substances: pollen, animal dander, dust mites. Also, there is a test for food allergens, but often it requires additional diagnostic methods.

Skin tests for allergens: types

Scarification test

A scarification allergy test is a notch on the skin of the forearm, through which the alleged antigen, in the form of a solution, easily enters the human body.

Prick test for allergens

Prick tests for allergies are made by introducing an antigen under the patient's skin, that is, they are a kind of injection. A typical testing area is the skin of the forearm, less often the back.

This allergy test allows you to detect sensitivity to insect venom, antibiotics and is not used to diagnose food allergies due to high risks of false positive results and the risk of anaphylaxis.

Application allergological tests (patch test)

This allergy test involves placing antigen-treated patches on the skin of the back for 48 hours. This test is done to detect delayed-type allergies. That is, it checks for reactions that occur after several hours or days after skin contact with the allergen, for example, contact dermatitis.

Provocative tests in allergology

Oral or nasal provocative allergy tests are done when a person is suspected of having an allergic reaction to a food or drug.

The procedure is carried out as follows: the suspected allergen, starting with very small doses, is eaten or inhaled under the close supervision of an allergist. If there is no reaction, the dose is increased until a positive response of the body to the antigen occurs.

rinse test

This procedure involves the diagnosis of food or drug intolerance, used for both true and false allergies.

After contact of the antigen with the oral mucosa, the number of leukocytes is assessed. Sensitivity to the substance causes inhibition of neutrophil emigration, which indicates the presence of an allergy.

Allergy tests at home

Do not attempt allergy testing at home. A self-administered food allergy test can cause anaphylaxis, a life-threatening reaction. A drug allergy test should also be carried out only in a medical facility under the supervision of a highly qualified specialist who can provide emergency assistance in case of an unfavorable course of testing.

Blood test for allergens

In the event that a person has any kind of allergy, samples are not the only way used in medicine to diagnose the disease. If a person does not have the opportunity to undergo tests due to age or he has a disease in the acute stage, you can always use an alternative diagnostic method and take an allergy test.

You can take allergy tests using this method at any time of the year, without waiting for the remission of the disease, in contrast to classical diagnostics.

Allergy blood tests are called allergy screening. This is a study in which the determination of general or specific Immunoglobulin E (IgE) is performed.

Immunoglobulin E (IgE) is a class of antibodies (immune proteins) associated with allergic reactions. In a healthy person, they are contained in the blood in small quantities, but with the manifestation of an allergy, their number can increase many times over.

An analysis for total IgE shows the amount of antibodies present in the blood, that is, it informs the doctor whether the person really has an allergy or whether the symptoms that have arisen are signs of another disease.

In order to identify a reaction to a specific allergen, a blood test for specific Immunoglobulin E (PAST allergy test) is performed. With this testing, sensitivity to respiratory, food, medicinal, mold, household and other antigens can be determined.

The disadvantages of this testing include the cost and expectation of the result within a few days.

Allergopanels: types

Today, blood allergy tests can be tested immediately for a complex of a wide range of antigens, which is an allergopanel. For the convenience of the patient, depending on the laboratory, the following types of allergopanels can be offered:

• food (vegetables, fruits, spices, additives, etc.);
• respiratory (pollen, mold fungi, dust, household allergens, etc.);
• mixed (food and inhalation antigens);
• pediatric (the most relevant allergens found in pediatrics);
• pre-vaccination (allergens included in vaccines);
• preoperative (anesthetics, latex, formaldehyde, etc.);
• diagnosis of a specific disease (asthma, rhinitis, eczema, etc.).

Where to do allergy testing?

You can do allergy tests for free at the clinic at the place of residence, having previously received a referral from the therapist. And also, you can take allergy tests in private medical centers that have an allergist on staff. The price of the study is on average 300 - 600 rubles per allergen.

Preparation for allergy tests

In order to get a reliable result, it is necessary to properly prepare for allergic tests.

1. Two weeks before the designated date of the study, it is necessary to stop taking antihistamines.
2. A few days before the procedure, alcohol is not allowed, the intake of fatty, fried foods is reduced.
3. On the eve of the study, you should measure the body temperature and make sure that you feel well.
4. With regards to taking blood: it is done on an empty stomach. Food should be consumed no more than 8 hours before the analysis. Otherwise, the test result may be false.

How are allergy tests taken?

Many people are unaware of how allergy tests are taken. Below we consider the main testing methods that exist today.

Scarification test. This type of testing uses needles (lancets) that slightly break the surface of the skin. However, the discomfort is so minimal that the samples are easily tolerated even by small children.

The process of sampling for allergies is as follows: after cleaning the test area with alcohol, the doctor makes marks with a marker on the skin, then, next to each mark, forms a slight scratch and drips the allergen extract over it. In this case, for each new substance, its own lancet is used. The procedure takes about 30 minutes.

In order to evaluate how adequately the skin responds to the tested substances, two additional agents are applied to the surface:

Histamine, which in most cases causes a reaction to it. If there is no reaction, this may indicate that this test may not detect allergies, even if the person actually has one.

Glycerin or saline. As a rule, they should not cause any reaction. However, if a person reacts to these substances, this indicates an increased sensitivity of the skin. Therefore, test results must be interpreted with care to avoid misdiagnosis of allergy.

prick test carried out as follows: a solution containing a suspicious allergen is applied to the skin of the forearm in the form of drops, which are then pierced with a special needle, thereby allowing them to enter the body. After 10-15 minutes, the doctor notes the reaction of the immune system to the antigen.

Patch tests does not involve the use of needles. Instead, the allergens are applied to patches that are placed on the surface of the back for 48 hours. During this time, you should avoid swimming and activities that cause sweating.

How are allergy tests done for children?

Many parents are interested in the question of how to test their child for allergies? In general, skin allergy tests in children are carried out in exactly the same way as in adults. Only on condition that the child, at the time of the procedure, was 5 years old.

Early childhood is a contraindication to testing because the immunity of the child before this age is not yet fully formed. In addition, it will be difficult for the baby to endure this rather lengthy process.

You can find out exactly what the child has an allergic reaction to by passing an analysis for a specific Immunoglobulin E. In this case, blood is taken from the child, which is tested for sensitivity to any allergens, regardless of the stage of the disease and the time of year.

Indications for an allergy test

Allergy testing is prescribed to make a correct diagnosis and determine further treatment, which includes limiting contact with the allergen, following a hypoallergenic diet, or replacing a medication that causes an increased reaction of the body.

As a rule, allergological tests are performed if a person has:

• allergic rhinitis (hay fever);
• allergic asthma;
• eczema, dermatitis of various etiologies;
• allergies to food, insect venom, mold, inhalant antigens, penicillin, or other drugs.

Allergen test contraindications

1. Taking antihistamines or psychotropic drugs such as antidepressants or antipsychotics a few days before the procedure may give a false negative result. And beta-blockers can increase sensitivity to allergens and increase allergic reactions. Therefore, before allergy tests, it is necessary to consult with your doctor and allergist.
2. Allergy skin tests are performed only if the testing area is healthy, that is, the person does not have eczema and other skin lesions.
3. Viral infection (ARVI), stress, oncology, pregnancy, autoimmune diseases, diabetes, exacerbation of allergies are also contraindications.
4. Allergy tests are carried out only in late autumn or in winter, when the period of remission of the disease begins.
5. Allergy tests also have age restrictions: children under 5 years old and older people over 60 years old can only be tested for an allergic reaction by taking a blood test.

Side effects

The most common side effects are redness, swelling and itching at the site of violation of the integrity of the skin. As a rule, these symptoms disappear within a few hours after the procedure.

With the right approach to the test, serious immediate allergic reactions occur in exceptional cases and are stopped with the help of drugs available in the doctor's office.

Skin allergy tests: decoding

An allergen test is considered positive if redness and slight swelling of the skin occurs at the site of a scratch or puncture, and also when an itchy blister forms, with a diameter of 5 mm or more.

Deciphering a skin test for allergens

Deciphering a blood test for allergies

Interpretation of blood test results should only be done by an allergist, as reference values ​​may vary depending on the laboratory.

Now you know what allergy tests are, when it is better to do them and how to decipher them. We wish you good health!

Everyone who suffers from the manifestations of allergic reactions understands how important it is to establish the cause that causes them. The best way to identify an allergen is to take an allergy test, which allows you to take into account the individual characteristics of the patient and the forms of manifestation of the disease.

Only with early diagnosis is it possible, if not a complete cure for an unpleasant disease, then at least the prevention of its further development.

Carried out to determine the stimulus to which the body responds with an allergic reaction. Knowing the annoying factor, the patient will be able to minimize contacts with him or at least reduce them in a situation where it is not possible to completely avoid interaction.

With prolonged contact with the allergen, a person runs the risk of acquiring chronic forms of the disease in the form of asthma or incurable dermatitis. It should also be borne in mind that the daily intake of antihistamines is addictive to them.

Samples are performed if the patient has the following and their manifestations:

• hay fever- a reaction to plant pollen, manifested in sneezing, runny nose, nasal congestion and swelling of the mucosa. Usually hay fever is seasonal.
• Bronchial asthma: accompanied by attacks of suffocation, coughing, heavy and labored breathing.
• food and on certain types of products or drugs: it has various forms of manifestation: skin rash, urticaria, asthmatic manifestations, and even.
• accompanied by itching, with an unknown cause of their occurrence.
• Conjunctivitis, manifested by lacrimation, itching and redness of the eyes.

Contraindications

• There are age restrictions for both adults and children. People over 60 and children under three should not be tested for allergies. There are also contraindications for women.
• Do not test pregnant and lactating mothers, you should also not come to the allergen detection procedure in the first days of menstruation.
• Testing should not be performed if the patient is taking glucocorticosteroid or other hormonal drugs. It is recommended to do tests 2-3 weeks after stopping these medications.

They never do testing for those people who have had at least once. Testing should not be performed on patients suffering from diseases such as AIDS, diabetes mellitus, mental disorders and oncology.

Types of Allergy Tests

Before making tests, the allergist must analyze the previous reactions of the body and determine the group of allergens that will be used in testing.

The procedure is carried out taking into account the age of the patient, his heredity, manifestations of the seasonality of the disease. For the adult population, professional activity is also taken into account.

All samples can be divided into the following categories:

Allergy blood tests

Blood from a vein is taken for analysis to find out which antibodies are present in a person. Usually they take a test for immunoglobulins E and G. This procedure is performed if the rest of the allergy tests cannot be done for any reason. In this case, it is necessary to prepare for the procedure for taking blood.

You should limit yourself to physical activity, follow a diet for at least three days, in which it is forbidden to eat fried, fatty, and foods that can cause. A complete cessation of alcohol and smoking is required. The analysis is carried out on an empty stomach.

It is prescribed for the following diseases:

• dermatitis and eczema;
• bronchial asthma.

Skin tests

Skin tests for allergies consist in the introduction of a certain dose of a substance (allergic irritant), showing the susceptibility of the human body to it.

Testing can be qualitative (the type of allergen is determined) and quantitative (shows the sensitivity of a person to the dose received). No more than 15-20 allergy tests should be done at a time. Small children at the age of 5 are given 2-3 tests.

• Scarification test, or prick test, considered to be the most widely used verification method. On the forearm, which is pre-cleaned, the alleged allergens are applied in the minimum dosage, and small incisions are made on the skin at the site of application using a special device - a scarifier. Scarification tests are recommended for severe manifestations of dermatitis, Quincke's edema, bronchial asthma. The accuracy of this method is 85%.
• skin test, or applique, is performed most often on the back and is done in the form of fastening strips with a liquid allergen, which is covered with a film and fixed with a plaster. It is carried out with various kinds of dermatitis. Examine the results of the reaction on the skin after 20 minutes, after 5 hours of exposure, and also after a day.
• Intradermal tests do in rare situations. The method consists in introducing an allergenic irritant under the skin. Perform such a test when determining an allergy of fungal or bacterial origin.

Provocative tests

The study of allergic reactions by the method of provocative tests is to act directly on the organ that most suffers from negative symptoms.

This allergen detection technique is more accurate than skin tests. But it is carried out extremely rarely, only when it was not possible to identify the irritant by any other means.

• nasal test performed using a special inhaler. It contains the alleged irritant. It is administered through the nasal passage by spraying onto the mucosa. If no reaction is observed, then the procedure is repeated with an increase in the concentration of the allergen. The repetition can be carried out up to 10 times. If no reaction is found after this, the sample is considered negative.
• Conjunctival test is based on the introduction of physiological fluid into one eye, after which, after 1/3 hour, an allergen with the maximum allowable dosage is dripped into the second eye. If a reaction is detected, the sample is counted as positive. This test cannot be performed with inflammation of the mucous membrane of the eye or with inflammation of the eyelids.
• inhalation test rarely carried out. Its use allows you to identify the allergen that affects the appearance of bronchospasm. The patient inhales an aerosol with a minimum dosage of the allergen. The procedure is repeated 5 times within an hour with a frequency of 10-15 minutes. If no reaction is noticed, then testing is repeated with an increased dose of the allergen.

The specifics of the tests

Any allergen testing must be done under the following conditions:

• Performed strictly on an empty stomach.
• Be sure to conduct tests in a medical institution and only medical specialists.
• In the room where samples are taken, they should be available to help with an unpredictable reaction. The application of samples should be carried out in the presence of a doctor. Even at the minimum dose of the injected allergen, a response of the body in the form of Quincke's edema can occur.
• It is possible to conduct a test only when at least 2-3 weeks have passed since the last exacerbation. Also, the patient should not suffer from colds and infectious diseases.
• The day before testing, you should stop taking any antihistamines in order to obtain a reliable result.

Features of conducting tests in children

Before testing, parents should prepare the child for this procedure. Before the samples, a clinical analysis of blood and urine should be taken.

Testing for allergens in children has its own characteristics. Children are often vaccinated against various diseases. Allergy testing can only be done 3 months after the next vaccination.

The doctor can also prescribe allergy tests for children as a preventive measure. if the next of kin suffer from a severe form of an allergic reaction. This should be done in order to establish the possibility of an allergic reaction of the body at the initial stage to prevent its development. For example, if a mother has pollinosis, then the probability that the child will suffer from the same disease increases to 75%.

The allergist must determine what form of allergy the child has. This will determine the choice of method for conducting tests, as well as at what age this procedure can be done. Children with a passive form are recommended to be tested no earlier than 5 years, since at this stage the body can cope with allergies on its own. For special indications, tests at the age of 3-4 years can be prescribed.

Usually in children, an allergen is detected in the form of skin tests.

Sample evaluation

After testing, it is important to correctly evaluate the results obtained. The doctor evaluates the samples according to the reaction rate. If the skin at the injection site of the allergen turns red, blistered, swollen during the first hour of the examination, then the reaction is considered instantaneous, and the test is positive. If the reaction to the injected allergen occurs after a day, then the test result is considered weakly positive.

Also, the reaction is evaluated by measuring the amount of reddening of the skin:

• no changes are observed - a negative test;
• up to 3 mm - doubtful reaction;
• over 3 mm - a positive reaction.

Most often, allergies are associated with a violation of the immune system. Therefore, if any type of allergic reaction is detected, measures should be taken to strengthen immunity.

There are various methods for conducting allergy tests. Which method of establishing the allergen should be chosen should be determined by the allergist. The choice of method is influenced by factors such as age, heredity, type of allergic reaction, seasonality of its manifestation. Once the irritant is identified, the patient will be able to avoid contact with it, which will help maintain their health.