If after eating certain foods there is discomfort, or in the spring itching in the nose, which is accompanied by sneezing, this does not mean that you are allergic 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 temporarily stop the attack.
An allergy is a reaction of an organism to any substance-stimulus, which can be either internal or external. Having discovered a threat, immune cells begin to fight it, while attacking the body of its own host.
It is not possible to establish a diagnosis of allergy based on patient complaints only. In addition, in order to accurately determine the substance that is the irritant, it is necessary to conduct an examination - a complex or in the context of certain tests - the doctor will tell you.
When do you need to be tested?
Analyzes for allergens must be taken with:
- Reactions to food (manifested as itching and skin rash).
- Seasonal or year-round exacerbation - hay fever.
- Drug Reactions.
- Bronchial asthma.
- Symptoms that may indicate the development of allergies.
You should know that an allergy in an adult manifests itself suddenly if the immune system is weakened, or a person first encountered an allergen.
Before prescribing tests for allergens, the doctor conducts a survey and examination of the patient. This is necessary to prevent an erroneous diagnosis (very similar symptoms in bronchial asthma or dermatitis).
When interviewing a patient, not only his complaints are taken into account: the doctor finds out whether someone in the family suffers from allergies, as a result of which a reaction manifests itself as soon as it makes itself felt. In addition, before the examination, it is necessary to pass a general blood test, according to the results of which you can judge whether there is an allergy, or is it another disease (a high content of eosinophils in the blood indicates the presence of allergies).
Types of analyzes
The substances that can cause the development of allergies are tens of thousands. To establish on the first try what specifically causes such a reaction is practically impossible. As a rule, doctors prescribe a comprehensive examination.
So, the types of allergen tests:
1. Skin tests. The local (skin) reaction of the body to the allergen is evaluated . This type of analysis does not give complications and does not provoke severe adverse reactions. The maximum that can develop is a slight swelling and a slight burning sensation.
An analysis is carried out in the absence of contraindications, which include:
- The acute phase of allergies.
- An exacerbation of a chronic disease.
- Pregnancy.
- Cramps.
With a skin test for an allergen, a reaction can be checked once for no more than 15 substances. An analysis is prescribed if the cause of the allergy is unknown, and the doctor needs to study the body's response to the most aggressive allergens.
Skin analysis methods are used for allergens:
- Animal hair.
- Dust.
- Food.
- Medical preparations.
Hand skin is treated with a solution with an allergen. And the method of application depends on the type of analysis:
- Skin tests - the solution is applied directly to the skin.
- Prik-test - the composition is processed on the skin, after which a thin needle is punctured in this area 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 with this type of analysis appears in the range from 30 minutes to 2 days and can be:
- Positive - redness and swelling are pronounced.
- Negative - there is no skin reaction to the 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 a weak one.
You should be aware that skin tests are tests for allergens in adults. As a rule, they are not given to children because the child's body can react very strongly to additional contact with the stimulus.
2. Blood test. There are cases when skin tests do not give a result or are contraindicated, then a blood test for an allergen is done - the method consists in detecting specific antibodies IgE, IgG, IgG4 in the blood for all kinds of allergens.
You can take 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 suspected allergens.
3. Elimination research. It is carried out if the patient often comes into contact with the suspected allergen, for example, dust, food, animal hair. It is supposed to exclude contact with the stimulus for a period of two weeks, and if the patient's condition improves, an allergen is identified. This method is used by most mothers in whom children react to a particular food product. According to their reviews, an allergen test is the safest for a child. Watching the baby’s reaction and excluding possible irritants, mothers remove high-risk products from the diet and monitor the baby’s condition.
4. The provocative method. It is carried out only in a hospital and is used in rare cases when other methods have been ineffective. The solution with the allergen is applied to the mucous membranes, and the doctor observes what reaction occurs and after how much. If suddenly the reaction is strong and there is a risk to life - the doctor will take measures to save the patient.
The advantages of the test are high reliability of the results. There are also disadvantages - the most dangerous among all research methods.
How to prepare for the analysis?
Analyzes are performed provided:
- The patient is healthy and has not been sick for the past 2 weeks.
- If a person has not taken medications (a special ban on hormonal and antihistamines).
- When several days are excluded contact with the suspected allergen.
- Recently, there have been no exacerbations of allergies or chronic diseases.
- The analysis is done on an empty stomach, before blood donation, a three-hour interval is allowed after the last meal.
- If a person has not been engaged in physical labor, loads for several days.
- If the patient did not smoke for a day and did not take alcohol
You should also be aware of the restrictions: skin tests are not performed for children under 4 years of age, for older people over 65, for lactating women, for pregnant women. This is due to the fact that an additional direct collision with an allergen can cause a serious exacerbation of the condition.
The main types of allergens
Allergens are substances that provoke an allergic reaction. And the reaction depends on the human immunity. The most common groups of allergens:
- Food - the reaction most often observed in patients to nuts, cereals, seafood, citrus fruits, milk, eggs, cocoa and chocolate, honey.
- Household dust allergens - causes a dust mite allergy.
- Animal allergens - allergies cause the coat and dander of dogs, cats, horses, rodents, birds. Sensitivity to these allergens is determined by skin testing.
- Pollen - a reaction to plant pollen. It manifests itself in the form of seasonal exacerbation, asthma, rhinitis. Allergies are caused not only by flowers, but also by trees, cereals, weeds.
- Inhaled allergens - insects and their metabolic products (bees, ants, cockroaches), latex, metal salts cause a reaction.
- Parasitological - allergies are caused by ticks, bacteria, fungi, as well as trichomonads, roundworms, giardia and other microorganisms.
- Medication - an allergy to drugs is easy to confuse with adverse reactions. An allergy usually develops on blood products, enzymes, vaccines, sulfonamides and antibiotics.
The 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 reaction of the body is weak and goes unnoticed.
You should also know that there are groups of interconnected 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 of allergens in children
Examination of babies does not differ from the diagnosis of the condition in adults. But, of course, there are a number of features that should be considered in pediatrics:
- Up to 6 months, an analysis of allergens in children with the determination of antibodies E is unreliable. At this age, the baby has maternal antibodies in the blood.
- In older children, a blood test helps confirm or refute the effect of a particular allergen.
- Skin tests are strictly prohibited for children under 4 years of age.
Explanation of the results
The test made is analyzed in the laboratory for 1-4 days, taking into account the age-related characteristics of the patient, since the number of antibodies changes in the human body with age. So, for example, the norm of immunoglobulin E is equal to 0.001 of the total content. The increase is associated with an increase in antibodies.
Explanation of indicators
The decoding of allergen tests is carried out by an experienced specialist who compares all the data and determines the exact picture of the reactions in the patient's body. Data is estimated according to the age of the patient
A significant excess of the norms indicates the presence of antigens to allergens and the presence of an allergic reaction, but may indicate other reactions in the body. That is why it is impossible to independently interpret the analyzes, and even more so to self-medicate.
Panels
Nowadays, panels are used for analysis - these are standard sets on which allergen markers are applied in a certain 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, protein of chicken eggs, milk, wheat flour, nuts, carrots, dust mite.
- Inhalation. It includes allergens: tick, pollen of alder, hazel, birch, forest oak, pollen of plantain, rye, wormwood, fungi, particles of skin and hair of a cat, horse, dog, guinea pigs, rabbits, hamsters.
- Food panel. An analysis of food allergens includes the following products: nuts, dairy products, egg yolk and protein, casein, celery, potatoes, tomatoes, carrots, soybeans, seafood, cod, apples, sesame, oranges, rye and wheat flour.
- Pediatric panel: dust mite, pollen of birch, grass, animal hair, fungus, casein, egg white and yolk, milk, carrots, soy, potatoes, peanuts, 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 border mean that there are no signs of allergy. The higher the indicator, the more sensitive the body is to the allergen.
After the test and identification of the substance that provokes an allergic reaction, the doctor makes a diagnosis and draws up an action plan based on eliminating or limiting the effect of the allergen on the patient’s body and on medical treatment. With an integrated approach, you can get rid of allergies very quickly.
Where can I get allergen tests?
Such studies are carried out in special clinics or in specialized laboratories. The direction for analysis is given either by a dermatologist or a pulmonologist.
It should be borne in mind that:
- Provocative tests and skin tests are an analysis method for allergens in adults. Children, as a rule, do not conduct these types of studies. They are done only in medical institutions, under the supervision of a doctor, since there is a risk of developing an acute reaction of the body.
- In children, pregnant women and the elderly, blood is taken for analysis to identify common immunoglobulins and antibodies.
- Children under one year old should not be tested, since the appearance of symptoms similar to allergies is most likely due to the introduction of new products into the diet.
Analyzes can be taken in any commercial laboratory, while the cost of each test should be ascertained in advance. Each clinic has its own pricing policy and the price for the same services can vary greatly.