If after eating a certain food there is discomfort, or itching in the nose in the spring, which is accompanied by sneezing, this does not mean that you have an allergy and you need to take medicine. Its symptoms can easily be confused with other diseases - an intestinal infection, a cold. In addition, antihistamines do not eliminate the cause, they stop the attack for a while.
Allergy is the reaction of the body to any substance-irritant, which can be both internal and external. Having detected a threat, immune cells begin to fight it, while attacking the body of its own host.
It is impossible to establish the diagnosis of "allergy" based only on the patient's complaints. In addition, in order to accurately determine the substance that is an irritant, it is necessary to conduct an examination - a comprehensive or in the context of certain tests - the doctor will tell.
When requiredneed to get tested?
Allergen tests must be done at:
- Reactions to food (manifested as itching and skin rash).
- Seasonal or year-round exacerbation - hay fever.
- Drug reactions.
- Asthma.
- Symptoms that may indicate the development of an allergy.
You should know that an allergy in an adult manifests itself suddenly, if the immune system is weakened, or the person first encountered the allergen.
Before prescribing tests for allergens, the doctor interviews and examines the patient. This is necessary to prevent misdiagnosis (very similar symptoms in bronchial asthma or dermatitis).
When interviewing a patient, not only his complaints are taken into account: the doctor finds out if someone in the family suffers from allergies, resulting in a reaction, as soon as it makes itself felt. In addition, before the examination, it is necessary to pass a general blood test, the results of which can be used to judge whether there is an allergy or another disease (high levels of eosinophils in the blood indicate an allergy).
Types of tests
Substances that can cause the development of allergies - tens of thousands. It is almost impossible to establish from the first time what exactly causes such a reaction. As a rule, doctors prescribe a comprehensive examination.
So, the types of tests for allergens:
1. Skin tests. The local (skin) reaction of the body to the allergen is evaluated. This kindanalysis does not give complications and does not provoke strong adverse reactions. The maximum that can develop is a slight swelling and a slight burning sensation.
The analysis is carried out in the absence of contraindications, which include:
- Acute phase of allergy.
- Exacerbation of a chronic disease.
- Pregnancy.
- Convulsions.
With a skin test for an allergen, you can test the reaction to no more than 15 substances at a time. The analysis is prescribed if the cause of the allergy is unknown, and the doctor needs to study the body's reaction to the most aggressive allergens.
Skin testing methods used for allergens:
- Animal wool.
- Dust.
- Food.
- Medicines.
The skin of the hands is treated with an allergen solution. And the application method depends on the type of analysis:
- Skin tests - the solution is applied directly to the skin.
- Prick test - the skin is processed with the composition, after which a puncture is made in this area with a thin needle to a depth of 1 mm.
- Scarification tests - the solution is applied to the skin, after which small scratches are made.
You should know that the analysis method is absolutely bloodless, all punctures and scratches are shallow, and the allergen does not enter the bloodstream.
The result of this type of analysis appears in the interval from 30 minutes to 2 days and can be:
- Positive - redness and swelling are pronounced.
- Negative - skin reaction tono allergen.
- Doubtful - there is a slight swelling, which can be attributed to microdamage to the skin or swelling from a neighboring allergen.
- Mild - there is a reaction to the allergen, but weak.
You should know that skin tests are allergen tests in adults. As a rule, they are not done to children due to the fact that the child's body can react very strongly to additional contact with an irritant.
2. Blood analysis. There are cases when skin tests do not give a result or are contraindicated, then they do a blood test for an allergen - the method consists in detecting specific IgE, IgG, IgG4 antibodies to various types of allergens in the blood.
You can pass such tests in any laboratory. But the type should be selected by a pulmonologist (allergist). Recently, comprehensive studies have been carried out that reveal a reaction to a group of alleged allergens.
3. elimination research. It is carried out if the patient often comes into contact with the alleged allergen, for example, dust, food, animal hair. It is supposed to exclude contact with the irritant for a period of two weeks, and if the patient's condition improves, the allergen has been identified. This method is used by most mothers whose children react to a particular food product. According to their reviews, the allergen test is the safest for the child. Watching the reaction of the baby and excluding possible irritants, mothers remove high-risk foods from the diet and monitorbaby's condition.
4. provocative method. It is performed only in the hospital and is used in rare cases when other methods have proven ineffective. A solution with an allergen is applied to the mucous membranes, and the doctor observes which reaction occurs and after how long. If suddenly the reaction turns out to be strong and there is a risk to life, the doctor will take measures to save the patient.
The advantage of the test is the high reliability of the results. There are also disadvantages - the most dangerous of all research methods.
How to prepare for the test?
Analyses are carried out under the condition:
- The patient is he althy and has not been sick for the past 2 weeks.
- If the person has not taken medication (special ban on hormonal and antihistamines).
- When contact with the alleged allergen is excluded for several days.
- Recently, there have been no exacerbations of allergies or chronic diseases.
- The test is done on an empty stomach, a three-hour interval after the last meal is allowed before donating blood.
- If a person has not been engaged in physical labor for several days, loads.
- If the patient has not smoked or taken alcohol for a day
You should also be aware of the restrictions: skin tests are not performed on children under 4 years old, the elderly over 65, lactating women, pregnant women. This is because additional direct exposure to the allergen can cause a serious aggravation of the condition.
Main types of allergens
Allergens are substances that provokeallergic reaction. And the reaction depends on the person's immunity. Most common allergen groups:
- Food - the most common reactions in patients are nuts, cereals, seafood, citrus fruits, milk, eggs, cocoa and chocolate, honey.
- House dust allergens - dust mites cause allergies.
- Animal allergens - cause allergies to hair and dander of dogs, cats, horses, rodents, birds. Sensitivity to these allergens is determined by skin testing.
- Pollen - a reaction to plant pollen. Manifested in the form of seasonal exacerbation, asthma, rhinitis. Allergies are caused not only by flowers, but also by trees, cereals, weeds.
- Inhalation allergens - insects and their waste products (bees, ants, cockroaches), latex, metal s alts cause a reaction.
- Parasitological - allergies are caused by ticks, bacteria, fungi, as well as Trichomonas, Ascaris, Giardia and other microorganisms.
- Drug-related – drug allergies are easily confused with adverse reactions. Allergies typically develop to blood products, enzymes, vaccines, sulfonamides, and antibiotics.
Reaction to one component is very rare, usually the body reacts to several substances. It's just that a person in everyday life either does not encounter allergens, or the body's reaction is weak and goes unnoticed.
You should also know that there are groups of interrelated allergens, if there is an allergy to nuts and wormwood, then a person will also be allergic to chamomile and cereals.
Features of the analysis for allergensin children
Examination of babies is no different from diagnosing a condition in adults. But there are, of course, a number of features that should be considered in pediatrics:
- Under 6 months of age, an allergen test in children with the determination of E antibodies is unreliable. At this age, the baby has mother's antibodies in the blood.
- In older children, a blood test helps confirm or refute the influence of a particular allergen.
- Skin testing is strictly prohibited for children under 4 years of age.
Explanations to the results obtained
The test done is analyzed in the laboratory within 1-4 days, the age feature of the patient is taken into account, since the number of antibodies in the human body changes with age. So, for example, the norm of immunoglobulin E is 0.001 of the total content. The increase in the indicator is associated with the growth of antibodies.
Deciphering indicators
An experienced specialist who compares all the data and determines the exact picture of reactions in the patient's body is engaged in decoding tests for allergens. The data is evaluated according to the age of the patient.
A significant excess of the norm indicates the presence of antigens to allergens and the presence of an allergic reaction, but may also indicate other reactions in the body. That is why it is impossible to interpret the tests on your own, and even more so to self-medicate.
Panels
Nowadays, panels are used for analysis - these are standardkits with allergen markers applied in a specific order.
Most often uses the following panels:
- Mixed. It includes such allergens: pollen of alder, hazel, birch catkins, various herbaceous plants, inflorescences of wormwood, plantain, hair and skin cells of a dog, cat, horse, soybeans, chicken egg protein, milk, wheat flour, nuts, carrots, dust tick.
- Inhalation. It includes allergens: mite, pollen of alder, hazel, birch, forest oak, pollen of plantain, rye, wormwood, fungi, particles of skin and hair of a cat, horse, dog, guinea pig, rabbit, hamster.
- Food panel. Food allergy testing includes: nuts, dairy, egg yolk and white, casein, celery, potatoes, tomatoes, carrots, soy, seafood, cod, apples, sesame, oranges, rye and wheat flour.
- Pediatric panel: dust mite, birch pollen, grass pollen, animal hair, fungus, casein, egg white and yolk, milk, carrot, soybean, potato, peanut, wheat flour, hazelnut.
The data obtained as a result of the analysis are estimated in the range from 0.35 to 100 kU/l. Indicators below the limit mean that there are no signs of allergy. The higher the indicator, the more sensitive the body to the allergen.
After the test and the identification of the substance that provokes an allergic reaction, the doctor makes a diagnosis and draws up an action plan based on the elimination or limitation of the allergen's effect on the patient's body and on drug treatment. With a comprehensive approach for allergiescan be disposed of very quickly.
Where can I get tested for allergens?
Such studies are carried out in special rooms of polyclinics or in specialized laboratories. A referral for analysis is given either by a dermatologist or a pulmonologist.
Keep in mind that:
- Provocative tests and skin tests are a method of testing for allergens in adults. Children, as a rule, do not conduct these types of research. They are made only in medical institutions, under the supervision of a doctor, as there is a risk of developing an acute reaction of the body.
- Children, pregnant women and the elderly are tested for blood tests to detect total immunoglobulins and antibodies.
- Children under one year old should not be tested, as the appearance of symptoms similar to allergies is most likely associated with the introduction of new foods into the diet.
Tests can be taken at any commercial laboratory, and the cost of each test should be clarified in advance. Each clinic has its own pricing policy and the price for the same services can vary greatly.
