Skin tests in allergology. Carrying out skin tests for allergens Setting up allergy tests

An allergic reaction can occur to food, animal skin particles, dust, mold, pollen from various plants, and much more.

To determine what exactly provokes a pathological immune response, the doctor prescribes examinations.

These include: a clinical standard blood and urine test, a biochemical blood test to determine class E immunoglobulins, and skin tests for allergens.

Indications for allergy tests

Only a doctor can refer you for tests and choose a method based on the overall picture of the reaction. Allergy skin tests are considered the most common and fastest.

Important points to know before starting testing:

Is this the first time this reaction has occurred or have there already been cases?
Patient's lifestyle.
Products consumed.
Was there any contact with any animals?
Does any of your relatives have similar symptoms?
What kind of bedding does a person use?
When and how did the first allergy symptoms appear?
What medications is the patient taking or has taken in the near future?
Chronic diseases in the patient.
Are there any acute infectious diseases today?
Whether the patient has ever had anaphylactic shock is a very important point. If the patient answers in the affirmative, then skin allergy tests cannot be performed.

Then the doctor conducts a visual examination of the patient.

Indications for prescribing allergy tests are:

formations on the skin - rash, redness, blisters, roughness, itching;
causeless rise in temperature;
prolonged coughing attacks that cannot be treated;
sudden runny nose and nasal congestion;
causeless lacrimation, itching, redness of the eyes;
relatives with allergies;
the patient noticed a direct dependence of the manifestations on food products, medicines, after contact with animals, during a stormy moment of flowering;
A blood test showed an increase in eosinophils and basophils.

The appearance of any allergic manifestations is the reason for performing skin tests.

Video from Dr. Malysheva:

Types of allergy tests

All examinations are carried out exclusively in medical institutions, since the medical staff has a specialized focus and experience. In the event of sudden unexpected reactions, they will be able to provide first emergency aid, which can save the victim’s life.

The following methods are used to conduct allergy tests:

Application tests are special strips on which certain allergens are applied, or a gauze cloth soaked in a concentrate with an allergen. The application is applied to the body and fixed.
Scarification test - a certain allergen concentrate is applied to a person’s skin and a scratch is made at the site of application with a scarifier.
– this is the application of the concentrate to the skin, after which a 1 mm puncture is made at the site of application with a special instrument.
Provocative methods are when the allergen is applied to the mucous membrane of the eyes or nasal mucosa, or inhalation is used to introduce the causative agent of the reaction.

Allergological study results

If a test is carried out using a scarifier or a prick test, the result is assessed 20 minutes after applying the allergen.

If the application test is chosen as the method, the result is assessed after two days.

The brighter the skin reaction, the greater the likelihood that a specific allergen caused the immune system to attack.

If there is no inflammation at the site of skin contact with the allergen, then the reaction is negative.

If the inflammation is up to two millimeters in size, then the reaction is called doubtful. If the inflamed area is larger than three millimeters in size, then this reaction is considered exactly positive.

Based on the diagnostic results, you can accurately determine which substances cause allergies, after which the doctor will select the correct treatment.

How are allergy tests done in adults?

It is better to do skin tests for allergies on autumn or winter days. During this period, the general allergic background is significantly lower, which will make it possible to obtain more accurate information as a result of the analysis.

To obtain reliable results, you should properly prepare for the study:

carry out skin tests only in a state of stable remission;
skin tests are best carried out on an empty stomach, the last meal should be at least 8 hours ago;
the day before, exclude all suspected allergens;
the study should be carried out in the morning;
do not drink alcohol in advance and do not smoke on the day of the test;
limit the intake of medications, especially antihistamines and hormonal medications, several days before the test.

There are contraindications when the test should be abandoned or postponed until better times:

pregnancy and breastfeeding;
age 60+;
infectious diseases;
violation of skin integrity;
previously had anaphylactic shock;
acute period of allergy.

All instruments used during the procedure must be disposable and sterile.

The protective sheath must be removed in the presence of the patient.

The laboratory worker must wear new sterile gloves before each patient and treat their hands with special disinfectant solutions. Before applying concentrated allergens, the application site is treated with alcohol.

No more than fifteen types of allergens can be applied to a person at a time.

If the application method is used, then the person must wear the attached bandage for two days without removing it. It is necessary to avoid water procedures for these two days so as not to distort the results.

Compliance with hygiene rules and rules of preparation for analysis will protect your health and help you obtain reliable results.

Allergy tests in children

Skin tests in children look the same as in adults. The exception is age. This diagnosis is not indicated for children under three years of age. The risks are too great and the result may be false.

Indirect skin tests

If direct skin tests do not give any result, then doctors move on to indirect tests. A healthy person is injected with serum from the patient's blood plasma under the skin. Every other day, an analysis is taken for the presence of antibodies and an allergen concentrate is applied to the site where the serum is injected. And again blood is taken for analysis.

This procedure is almost never used nowadays, as there are great risks to health:

possible infection with hidden infections from the donor;
a violent reaction to an allergen is possible.

Therefore, the modern world is increasingly abandoning the indirect method for allergens.

Skin tests

Pediatric allergists often prescribe skin tests for allergens in children.

But there are a number of contraindications:

age up to 3 years;
acute period of allergy;
acute infectious and inflammatory disease;
long-term use of hormonal drugs;
previously had an anaphylactic condition.

In preparation for the analysis, it is necessary to remove possible allergens from the child’s daily life. Children can be tested three hours after eating.

It is important to use only sterile and disposable instruments when testing. In a medical institution where diagnostics are carried out, there must certainly be an anti-shock first aid kit in order to provide emergency assistance in a timely manner if a violent reaction to allergens occurs.

The results of the study can be assessed 20 minutes after applying the pathogen to the skin.

Allergen panels

For more accurate and safe diagnosis, pediatric allergen panels are used.

With their help you can identify the following allergens:

food;
vegetable;
animals;
for milk protein;
for dust mites.

This procedure is considered completely safe for the child, since there is no moment of child contact directly with the allergen. This test can be carried out on children almost from birth, but a more accurate result can be obtained from six months of age.

Post-diagnosis results can be obtained within a week after the blood is drawn. The laboratory's response must be assessed by a physician. According to reports, he will prescribe the required treatment.

Signs of allergies need to be suppressed at the earliest stages to prevent further deterioration of health. A qualified doctor will help determine the exact cause of the body’s violent reaction. He will prescribe the required studies, conduct a thorough examination and interview the patient, which will help him make an accurate diagnosis and prescribe the correct treatment.

What are skin tests? Any allergy manifests itself with similar symptoms, although its causes may be different. Sometimes it is difficult to find out the exact cause, and in some cases it is not possible at all. Doctors recommend skin tests. Skin prick testing is a very commonly used method in allergology; doctors use it to establish the correct diagnosis.

Medical indications

allergic rhinitis or dermatitis;
asthma;
food allergies;
atopic dermatitis;
seasonal allergies.

The procedure involves introducing an allergen through the skin; most often this analysis is recommended to be carried out during the remission stage, but not earlier than 30 days from the end of the acute stage of the disease.

In some cases, skin testing for allergens is not possible. For example, if the patient:

exacerbation stage;
decompensated asthmatic disease;
serious infectious processes;
if there are pathologies in the kidneys or liver;
for autoimmune diseases;
if there is a possibility of developing anaphylactic shock;
for oncology;
for psychoneurological diseases;
during pregnancy and lactation.

Types of skin tests

In modern medicine, there are several types of skin tests:

application - in which a tampon soaked in an allergen is applied to the skin;
scarification tests - the patient is sprayed or dripped with allergen into the forearm area, and then the skin is slightly injured by scratches;
prick tests - characterized by the fact that the irritant is dripped, after which a small puncture is made with a needle;
less often, provocateurs are injected under the skin.

After the procedure, the doctor evaluates the patient’s reaction to a particular stimulus. You can test for 15 allergens at one time. The solutions contain animal hair and skin particles, plant pollen, food products, insect poisons, chemicals, dust, etc. Sometimes such an analysis does not provide guaranteed confidence, and then the patient is prescribed a blood test. Skin tests are used if the reaction to the allergen occurs quickly. If the patient’s symptoms differ from the results obtained, then the doctor performs provocative tests.

How to prepare for the procedure?

Before registering a patient for skin testing, the doctor instructs the patient in detail about how the procedure will be performed, what complications may occur, and what not to do before the procedure. After the patient is tested, he must remain in a medical facility for some time so that he can receive help if his condition worsens. 24 hours before the test, the patient should stop taking antihistamines and antiallergic drugs. Skin tests are not performed for persons over 60 years of age.

There is no difference in performing a skin test on a child and an adult. However, provocative studies are contraindicated for children. In addition, such an analysis is not performed for children under 3-5 years of age, because a child’s body may, after a couple of years, produce a different reaction to certain allergens.

Additional diagnostic measures

It happens that skin tests do not reveal an allergen in a patient, but all the symptoms of an allergy are present. In this case, additional diagnostic methods are used. Provocative tests have already been discussed above, now let’s look at their types:

Conjunctival - in this case, the irritant is injected directly into the conjunctival sac of the eye.
Nasal - the allergen is injected directly into the nose.
Inhalation - used in diagnosing bronchial asthma. The patient is asked to inhale the allergen through the nose.
Exposure - the doctor simulates the situation, and the patient’s contact with the provoking factor occurs in a natural setting.
Temperature - a specialist studies how the body reacts to heat and cold.
Elimination - in this case, the suspected allergen is excluded from contact with a person.
Thrombocytopenic and leukocytopenic - after the introduction of an allergen into the patient’s blood, leukocytes and platelets are counted. Provided that their number decreases, we can say that the stimulus has been identified.
Radioallergosorbent test. A radioactive tracer is injected into the patient's blood. Based on how antibodies interact with the antigen, a conclusion is drawn about the concentration of the allergen.

The latter method is much more sensitive than all others and can detect even very small concentrations of the allergen. But its cost is quite high, and it is used when it is impossible to carry out other tests, or if they do not give accurate results.

Decoding the results

If there is no reaction, then the test is negative. If a slight redness appears on the skin, but without the appearance of papules, then it is considered that this is a questionable result, and a more accurate diagnosis is necessary. If a blister measuring 3 mm appears on the skin and the redness is more pronounced, then the result is considered weakly positive. The reaction is considered positive when there is severe redness and when the papule reaches 5 mm or more. If a papule of 10 mm is formed, then this result is considered sharply positive.

A false result may occur for the following reasons:

incorrect placement of scratches;
the properties of the allergen have changed as a result of their improper storage;
low skin reaction;
the patient is taking medications that inhibit the reaction.

Actions after research

Once the cause of the allergy is determined, the patient should stop contacting the allergen. If the allergy is caused by a medicine, then its use should be stopped, if it is some kind of food product, then it should be excluded from the diet, etc. After this, the doctor will prescribe antihistamines to the patient or suggest allergy vaccination.

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The drugs are taken during an exacerbation of the disease and can abruptly stop an allergic attack. But at the same time, they can cause some negative phenomena - problems with the gastrointestinal tract, drowsiness and depression may appear, appetite may increase; if such drugs are taken for a long time, their therapeutic effect is reduced. There are new generation drugs, they are also highly effective in use and have less pronounced side effects.

Allergy vaccination is the introduction of small doses of an allergen into the body, gradually the body gets used to the irritant and begins to produce antibodies. It must be said that this is a long process and can take several years. At first, 40 injections are given every other day, then gradually less and less. In the end, it comes to the point that the patient must receive a dose once a month, but no one can say how long it will take for the body to completely get used to it.

Skin tests for allergens are a highly informative method for determining the irritant in case of hypersensitivity of the body. The technique is simple and effective, with minimal discomfort for the patient.

It is important to know the indications and contraindications for performing prick tests, prick tests and special applications. Rules for preparing for the study, the course of the procedure, types of reactions, results are described in the article.

Skin tests: what are they?

The technique allows you to determine the type of allergen and the type of negative reaction:

when an allergen comes into contact with the skin, interaction with mast cells occurs;
local allergic signs occur after the penetration of an irritant into a wound on the skin, with the release of serotonin and histamine;
in the area where an irritant dangerous to the patient is applied, the epidermis turns red, itches, papules often appear, the site of a scratch, application or injection swells;
Based on the results of the appearance of allergenic foci, doctors determine the types of irritants, contact with which will have to be excluded.

Mandatory elements of skin tests are solutions and extracts of various types of allergens. Doctors use glycerin and histamine to determine if the test is correct. A reaction to histamine occurs in most cases; the absence of even a weak response on the skin indicates possible errors in skin testing. To apply irritants, use a needle, lancet or tampon applicator.

In what cases are studies prescribed?

Indications for skin tests:

(hay fever);
intolerance to certain products and substances in food (lactose, gluten);

Contraindications

Doctors do not conduct testing in the following cases:

infectious diseases with severe course: bronchitis, sore throat, pneumonia;
the patient has been diagnosed with AIDS or autoimmune pathologies;
high risk of anaphylactic reactions;
lactation period;
decompensated stage of asthmatic disease;
pregnancy;
a malignant tumor has been identified;
exacerbation of allergic symptoms;
mental disorders.

Note! There are relative and absolute contraindications. In some conditions and diseases (pregnancy, sore throat, pneumonia, relapse of allergies), even a minimal dose of the irritant cannot be administered, but after recovery or the birth of the baby, studies are allowed. In case of absolute contraindications, other diagnostic methods are used, for example, a safe, highly informative blood test for antibodies (food allergen panel).

Types of testing

To identify allergens, doctors conduct several types of testing:

scarification tests. The doctor applies irritant particles to the forearm and makes small scratches with a needle or lancet;
application tests. A safe method does not require even minimal damage to the epidermis: the doctor applies a tampon moistened with an allergen solution to the body;
prick tests. The healthcare worker applies a drop of irritant to the skin, then uses a special needle to carefully pierce the testing area.

What are direct and indirect samples?

Allergists conduct certain types of studies involving the upper layer of the epidermis in the process. The methods are effective in diagnosing allergic diseases, clarifying the diagnosis or type of irritant.

Features of skin tests:

direct allergy tests. The examination is carried out to diagnose diseases that develop due to intolerance to certain substances. During direct tests, the possible allergen and the epidermis are in close contact: applications, scarification tests, and prick tests are carried out;
indirect skin tests. The technique was developed to determine the type of allergic reaction. First, the suspected irritant is administered subcutaneously; after a certain period, the doctor prescribes a venous blood sample to determine the level of antibodies;
provocative tests. The technology is used only when other methods have low information content or false positive/false negative test results. The method allows you to clarify the diagnosis if the data from previous tests and anamnesis do not match. The Prausnitz-Küstren reaction is the injection of blood serum from an allergic person to a healthy person. A day later, the doctor determines the level of antibodies in the epidermis, then the same area is treated with an allergen and the reaction is observed.

Preparation for the procedure

discontinuation of glucocorticosteroids and antihistamines 14 days before testing;
compliance with previously assigned. Test results performed on an empty stomach may be incorrect.

The patient must strictly follow the rules determined by the doctor. False-positive and false-negative results of skin tests are possible if recommendations are not followed. If the picture is “blurred”, you will have to repeat the study again, using microdoses of allergens, which creates some discomfort for the patient. To clarify the diagnosis, additional medications are prescribed, many of which are not cheap.

How is allergen testing performed?

Features of the scarification test:

before scratching, the epidermis is wiped with 70% alcohol;
testing in children is carried out in the upper back, in adults - in the forearm area;
on the treated area of the epidermis, the doctor makes small scratches, the distance between them is from 4 to 5 cm. If the procedure is carried out incorrectly (the marks are too close), inaccurate results are often obtained);
Using a sterile needle or lancet, the doctor applies extracts or solutions of allergens. For each type of stimulus, the specialist takes a new tool;
for 15 minutes the patient must hold his hand motionless so that the drops of irritants do not mix, the result is reliable;
Based on the reaction on the surface of the epidermis in the scratch area, the doctor determines whether this substance is dangerous for a particular person or not. Papules, redness, itching, swelling in a certain area indicate a negative response to this component;
The test result is noticeable after a quarter of an hour. After taking measurements and analyzing the situation, the doctor removes the remaining drops of irritant from the scratches. A maximum of twenty allergens can be applied in one procedure.

A prerequisite for correct diagnosis and the absence of complications after the procedure is highly qualified medical personnel. Doctors and nurses must have diplomas and certificates confirming the right to conduct special research. Experience is an important point that you should pay attention to when choosing a medical institution: the body of some patients reacts violently to the management of allergens, anaphylactic reactions develop, and prompt and competent medical assistance is required to prevent serious consequences.

Diagnostic results

Skin tests are a highly informative method that allows you to determine the degree of danger of a substance for a particular patient:

sharply positive test result- pronounced redness, papule measuring 10 mm or more;
positive reaction- redness is clearly visible, the papule reaches 5 mm;
weakly positive result- severe hyperemia, papule no more than 3 mm in size;
dubious outcome- there is no papule, but the skin is red. To clarify the diagnosis, a blood test is prescribed for comparison with a panel of allergens or another type of study at the discretion of the doctor;
negative result- there are no skin reactions on the surface of the epidermis in the scratch area.

False results: reasons

Doctors identify several factors against which inaccurate data is possible:

taking or taking other medications that inhibit the development of an allergic reaction;
incorrect procedure;
decreased skin reaction in a particular patient during a certain period, more often in children and the elderly;
storage of allergen extracts in violation of instructions, which leads to changes in properties;
testing for a substance that is not the main irritant;
The concentration of the solution prepared by the nurse is too low.

For this reason, personnel must quickly respond to acute symptoms and competently stop signs of life-threatening manifestations. With timely desensitization of the body, negative symptoms decrease after a certain time. The period of disappearance of pronounced swelling, normalization of pressure, elimination of blisters depends on the severity of the case.

Skin tests using extracts and solutions of irritants can determine in 15-20 minutes whether a particular substance is an allergen or not. The technique is quite safe, the procedure is simple, discomfort is minimal, and complications occur in rare cases. An important condition is that skin testing be carried out by competent personnel in a medical institution.

How are skin tests performed and what do they show to determine the allergen? Find out more after watching the following video:

Skin allergy tests are a diagnostic method for identifying specific sensitization of the body by introducing an allergen through the skin and assessing the magnitude and nature of the swelling or inflammatory reaction that develops. Skin tests (ST) are usually performed during the period of remission. There are qualitative and quantitative, direct and passive skin tests.

Quantitative tests give an idea of the degree of sensitization. They are placed to identify individual sensitivity and resolve the issue of initial doses of the allergen when carrying out specific hyposensitization.

In direct skin allergy tests, the allergen is administered to the patient being studied. In passive or indirect skin allergy tests, the patient’s blood serum is injected intradermally into a healthy person, and then the allergen is injected into the injection sites of the serum (Prausnitz-Küstner reaction).

The time at which a skin reaction appears after exposure to an allergen and its nature depend on the type of allergic reaction. With the reagin type, the reaction appears in the first 10-20 minutes. It is a round or irregular blister with pseudopodia. The color of the blister is pinkish or pale with an area of arterial hyperemia around it. Its development is based on acutely developing limited swelling of the papillary layer of the skin due to increased vascular permeability. This reaction is called a wheal, urticarial or immediate type reaction. In allergic processes of types III and IV, the skin reaction is an acute inflammation with all its signs - redness, swelling, increased temperature in the area of inflammation and pain. The difference between type III and IV lies in the time of development and intensity of inflammation. In type III, inflammation is more pronounced, it appears after 4-6 hours and goes away after 12-24 hours. In type IV, inflammation reaches its maximum development after 24-48 hours. Thus, using skin allergic tests, you can determine the type of allergic reaction to this allergen.

Depending on the specifics of the case, different methods of performing skin allergy tests are used. The choice of method depends on:

type of disease;
expected type of allergic reaction;
the presumed group affiliation of the allergen.

What are allergy tests?

Allergy tests on the skin are the most well-known diagnostic method for determining substances to which a person exhibits an increased reaction of the body. Their popularity is explained by the fact that they are practically painless and cover a wide range of allergens, especially those related to airborne substances: pollen, animal dander, dust mites. There is also a test for food allergens, but it often requires additional diagnostic methods.

Skin tests for allergens: types

Scarification test

A scarification allergy test consists of incisions on the skin of the forearm, through which the expected antigen, in the form of a solution, easily penetrates the human body.

This type of study allows you to check for respiratory and household allergens.

Prick test for allergens

Prick allergy tests are performed by introducing an antigen under the patient’s skin, that is, they represent a kind of injection. A typical testing area is the skin of the forearm, less often the back.

It is worth noting that intradermal tests are more sensitive than prick tests.

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

Allergy patch tests (patch test)

This allergy test involves applying antigen-treated patches to the skin of the back for 48 hours. This examination is carried out to identify delayed-type allergies. That is, reactions that occur after several hours or days after skin contact with an allergen are tested, for example, contact dermatitis.

The patch test allows you to check your reaction to latex, metals, fragrances, medications, preservatives, resins, hair dyes, etc.

Provocative tests in allergology

Oral or nasal allergy provocation tests are performed when there is a suspicion that a person has an allergic reaction to food or medications.

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 the body shows a positive response to the antigen.

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 tests at home. Self-administered food allergy testing can cause anaphylaxis, a life-threatening reaction. A drug allergy test should also be carried out only in a medical institution 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 exhibits any kind of allergy, tests are not the only method used in medicine to diagnose the disease. If a person is unable to undergo tests due to age or his disease is 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 remission of the disease, unlike classical diagnostics.

You can donate blood for allergy tests at a specialized medical center. The advantage of this method is that it is not able to provoke anaphylaxis, and taking antihistamines does not affect the result.

Blood tests for allergies are called allergy screening. This is a test in which total or specific Immunoglobulin E (IgE) is determined.

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 when an allergy occurs, 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 a 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 is performed for specific Immunoglobulin E (PACT allergy test). With this testing, it is possible to determine sensitivity to respiratory, food, drug, mold, household and other antigens.

The disadvantages of this testing include the cost and waiting for results within several days.

Allergy panels: types

Today, blood allergy tests can be tested immediately for a complex of a wide range of antigens, which is an allergy panel. For the convenience of the patient, depending on the laboratory, the following types of allergy panels may 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 can I get allergy tests done?

Allergy tests can be done free of charge at the clinic at your place of residence, having previously received a referral from a therapist. You can also take allergy tests at private medical centers that have an allergist on staff. The cost of research on average is 300 - 600 rubles per allergen.

Preparing for allergy tests

In order to get a reliable result, you should properly prepare for allergy tests.

Two weeks before the designated date of the study, you must stop taking antihistamines.
A few days before the procedure, alcohol consumption is not allowed, and the intake of fatty and fried foods is reduced.
On the eve of the study, you should measure your body temperature and make sure that you are feeling normal.
Regarding blood collection: it is done on an empty stomach. Food should be consumed no more than 8 hours before the test. Otherwise, the result of the test may be false.

How are allergy tests taken?

Many people have no idea how allergy testing is done. Below we will consider the main testing methods that exist today.

Skin tests for allergies are carried out in different ways, depending on the method of diagnosis.

Scarification test. This type of testing uses needles (lancets) that lightly damage the surface of the skin. However, the discomfort is so minimal that the tests can be easily tolerated even by small children.

The process of taking an allergy test is as follows: after cleaning the test area with alcohol, the doctor makes marks on the skin with a marker, then, next to each mark, creates a minor scratch and drips the allergen extract on top of it. At the same time, each new substance uses its own lancet. The procedure takes about 30 minutes.

In order to assess how adequately the skin reacts 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 the test may not detect an allergy, even if the person actually has one.

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

Prick test is 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 penetrate the body. After 10-15 minutes, the doctor notes the reaction of the immune system to the antigen.

Patch tests do not involve the use of needles. Instead, allergens are applied to patches that are placed on 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 check for allergies in their child? In general, allergy skin tests in children are carried out in the same way as in adults. Only provided that the child is 5 years old at the time of the procedure.

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

The most common allergy test for children is a blood test for specific IgE.

You can find out what exactly the child is allergic to by taking a test for specific Immunoglobulin E. In this case, the child’s blood is taken and tested for sensitivity to any allergens, regardless of the stage of the disease and the time of year.

Indications for allergy testing

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, allergy tests are performed if a person has:

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

Contraindications for allergen testing

Taking antihistamines or psychotropic medications, such as antidepressants or antipsychotics, several 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 testing, it is necessary to consult with your doctor and allergist.
Allergy skin tests are performed only if the testing area is healthy, that is, the person does not have eczema or other skin lesions.
Viral infection (ARVI), stress, oncology, pregnancy, autoimmune diseases, diabetes, exacerbation of allergies are also contraindications.
Allergy tests are carried out only in late autumn or winter, when the period of remission of the disease begins.
Allergy tests also have age restrictions: children under 5 years of age and elderly people over 60 years of age 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 the skin break. As a rule, these symptoms disappear a few hours after the procedure.

With the correct approach to the test, serious immediate allergic reactions occur in exceptional cases and can be treated with medications available in the doctor’s office.

Skin allergy tests: explanation

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

Photo: positive allergen test result

Deciphering the skin test for allergens

Interpretation of the scarification allergy test

Interpretation of intradermal allergy test

Interpretation of a blood test for allergies

Interpretation of blood test results should only be carried out by an allergist, since reference values may vary depending on the laboratory.

Normal level of Immunoglobulin E in blood serum.

Increased levels of Immunoglobulin E in pathological conditions.

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