Methods for diagnosing allergies

Successful treatment and prevention of allergic manifestations largely depend on the establishment of the root cause, which can be very difficult to do.

First, the difficulty of detecting the primary factors that cause allergies may be due to cross-reactions. Secondly, if “pseudoallergy” is suspected, it is necessary to conduct a more thorough examination of the body’s internal systems - digestive, endocrine, lymphatic and immune. If there are no violations from metabolic processes, as well as signs of chronic infections, an important task is a comprehensive study of the state of immunity and the diagnosis of allergies.

Based on a thorough study of the body and determining the cause of allergy, individual therapy is selected, leading to recovery.

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

Allergy testing available is divided into: 

• conducted with the participation of the person (in vivo) - tests on the skin, mucous membranes, sublingual zone; 
• contactless technologies based on the determination of the serum reaction in the interaction with the allergen (in vitro).

The most accessible and common method of diagnosing allergies is a skin test. Among the advantages of this test are illustrative and low cost.

Methods for diagnosing allergies include provocative testing - the portion introduction of the suspected pathogen into the body.

The condition of the elimination method is the abolition of the drug or the exclusion from the diet of the allergen product.

A relatively new diagnosis of allergy is the method of Follya. Bioresonance research is carried out on special equipment, with the help of which information is read from biologically active points. The method produces reliable results, subject to testing by a qualified technician.

It should be noted that the data of any diagnosis of allergies are considered reliable for six months from the date of the study.

Diagnosis of Allergies in Children

In order to study the course of allergic diseases in babies and draw up therapeutic schemes, a series of special tests are conducted.

[5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15]

Skin test method

Allergy diagnostics in children using the allergy test method is widely used to establish sensitivity to an allergen. Skin testing with a set of allergens can be in the form of: an injection (prick-test), scratches (scarification method) and an intracutaneous test.

The indications for the study are allergic manifestations of food, respiratory, medicinal nature, as well as atopic dermatitis and bronchial asthma.

The test is not carried out if: 

• there is an exacerbation of existing allergies or other chronic diseases; 
• the baby has contracted an infection (flu, ARVI, etc.); 
• the condition is quite heavy; 
• For the purpose of treatment, drugs containing hormones (corticosteroids) were used.

At the beginning of a diagnostic study, consultation with a pediatrician is mandatory, and laboratory findings such as urinalysis, as well as general and blood tests for biochemistry.

The kit for skin testing includes the most common allergens: food, animal epithelium particles, wool, down, pollen, house dust and others. The skin test is carried out from the inner surface of the forearm (at a distance of 3 cm above the carpal region). If the subject's skin has allergic signs, then unaffected areas (for example, the back) are subjected to testing.

Allergy tests are prohibited for children under five years of age. The formation of the immune system at this age, as a rule, is not completed and this is fraught with a number of complications, including chronic diseases. The procedure itself is painful.

During testing, an allergen is applied to the injection site / scratch, after which swelling and redness of the skin may appear. Such a reaction will indicate the presence of allergies. Test results are checked after 24 or 48 hours with the obligatory condition of bright light. If the skin rash element is more than 2 mm in diameter, then the testing is considered positive. Up to 20 allergens are tested per diagnosis.

Before diagnosing an allergy, it is important to stop taking anti-allergic medicines, otherwise the tests are considered erroneous.

[16], [17], [18], [19], [20], [21], [22]

Method for identifying groups of specific Ig E antibodies

Diagnosis of allergies in children under the age of five years, consists in the collection of venous blood to identify specific immunoglobulins. This technology allows to evaluate more than 200 allergens and helps to accurately determine the cause of the disease. The method has no contraindications, since there is no contact of the patient’s body with the pathogen under test. The presence of allergy is determined by the reaction of blood serum in the process of interaction with the allergen.

Indications of the study are not only the allergic manifestations themselves. Using this technique, it is possible to estimate the risk of allergies in children, in the genus of which similar pathologies are noted.

Recommend to reduce physical and mental stress for a few days before the diagnosis of allergies.

[23], [24], [25]

Detection method for specific IgG

This diagnosis is used in food allergies in children. The list of allergen products includes the most common fruits, vegetables, cheeses, fish and poultry meat, dairy products, nuts, etc.

The material for the study is serum.

[26], [27], [28], [29]

Diagnosis of food allergies

The study of food allergic reactions carried out by the following methods: 

• allergy tests; 
• non-contact methods (serum); 
• provocation; 
• with the help of diets.

Regarding skin tests, as a way to diagnose allergies, the opinions of doctors are divided. Some of them completely reject this method in the case of food allergies, when others select an elimination diet according to the results of a skin test.

The technology of testing is based on a scarification test, when the expected allergen diluted in a certain proportion is applied to the forearm scratch / injection area.

The diagnosis of food allergy by the reaction of blood serum depends, as in skin testing, on the quality of the allergen (quantitative dose in the mixture for the sample). These methods are aimed at detecting antibodies IgG, IgE and IgM. The research problems are the instability of allergens and possible cross-reactions. There is a difficulty in interpreting positive results in cases of slow or chronic reactions, rather than in acute reactions.

Food provocations are carried out with full medical supervision. A variety of products, including the suspected allergen, are placed in a special capsule by a third-party health care professional (so that neither the doctor nor the patient should be aware of the contents). An allergen product may be masked by another food. The essence of the method consists in the fact that, upon the occurrence of a reaction only to an allergen, it is possible to conclude a positive result in the diagnosis of allergy.

Patients with severe food allergies are not exposed to food provocation in order to avoid serious consequences.

Food diary very often clarifies and helps to track the relationship between products and the manifestation of an allergic reaction.

Allergy diagnostics is also carried out by an elimination diet, in which the alleged allergen is completely excluded from the diet. If after this symptoms disappear, then a diagnosis is made - food allergy.

[30], [31], [32], [33], [34], [35]

Diagnosis of drug allergies

The process of questioning the patient and the subsequent analysis of an allergic history of medicinal substances, most often, allow you to establish the correct diagnosis.

Criteria for drug allergic reactions: 

• clinical manifestations associated with taking the drug; 
• there comes a significant relief or complete relief from symptoms associated with the abolition of the drug; 
• allergy-like manifestations of a toxic, pharmacological nature and other adverse events are excluded; 
• the presence of a latent sensitizing period in the case of the first intake of a substance.

Laboratory diagnosis of drug allergy, as well as provocative tests are used if a detailed study of the history did not help identify the allergen.

To determine the drug-allergen used such laboratory studies: 

• enzyme immunoassay - developed for a relatively small group of pharmacological agents, including: gentamicin, a number of beta-lactam-type antibiotics, lidocaine, acetylsalicylic acid. Testing is possible when taking from the patient 1 ml of serum. The duration of the study reaches 18 hours; 
• Shelly testing - more suitable for scientific experiments requiring specially trained personnel; 
• Fluorescent allergy diagnostics has been developed for antibiotics, nonsteroidal anti-inflammatory drugs, anesthetics, a number of vitamins, etc. The test lasts about half an hour, and 1 ml of blood is enough to test ten medications; 
• testing the inhibition of natural emigration of leukocytes (TTEEL) - known for more than 30 years, is used for antibiotics, local anesthetics, sulfa drugs, a number of non-steroidal anti-inflammatory substances. To get the result you need an hour and a half. Disadvantages of the method - do not use when examining children under 5 years old, patients with inflammation of the oral cavity, as well as in the acute course of allergic processes.

Skin tests to diagnose drug allergies are not widespread, since the reliability of the results does not exceed 60%. The scarification method and the prick test were developed only for a number of beta-lactam antibiotics. The use of these methods is unacceptable in patients with severe allergies (angioedema, anaphylaxis, etc.).

Application techniques - the most informative way to diagnose allergies in contact dermatitis. The test is carried out on the skin moisturized with saline (the area between the shoulder blades), provided that there are no allergic manifestations on it. In this area, a camera is attached to the patch with an intended allergen medication that contacts the skin. Twenty minutes later, the presence of an instantaneous type of reaction is checked; if it is not detected, the dressing is left for up to 72 hours.

Diagnosis using provocative tests is rarely used when the results of a thorough study of history and laboratory data have not established the relationship between clinical manifestations and the drug, and there is no possibility to cancel the drug. Such testing is carried out strictly under the supervision of a specialist in resuscitation readiness.

Contraindications for provocative testing: 

• allergy exacerbation period; 
• previous anaphylaxis; 
• diseases of the endocrine and cardiac systems in severe form, as well as liver and kidneys; 
• pregnancy; 
• age up to 5 years.

Diagnosis of allergy by provocation on drugs in tablets is carried out by sublingual breakdown, when a fourth part of the tablet substance is placed under the tongue of the patient (you can check the drops, causing them to sugar). Itching in the mouth, swelling, redness after a short period of time will indicate a positive result and the presence of allergies.

Another provocative method is the dosed introduction of the proposed allergen (starting with small doses) subcutaneously and determining the reaction after half an hour.

[36], [37], [38], [39], [40], [41], [42], [43]

Laboratory diagnosis of allergies

Laboratory diagnosis of allergies - the most current method, including: 

• radioallergy testing for the detection of specific immunoglobulin classes E, M, G, conducted on the basis of blood serum; 
• ELISA technology for detecting specific immunoglobulin classes E, M, G using the serum of the subject; 
• study of changes in the basophils of the blood serum in the process of contact with the allergen or the method of Shayley (determines only the state of sensitization itself); 
• reactions from blast transformation / inhibition of leukocyte migration.

Immunoassay has several disadvantages: 

• low sensitivity of the test (ie, there is an allergy, but the diagnosis does not reveal it); 
• on the contrary, high sensitivity with low specificity, which leads to a false-positive reaction (as a result of testing, an allergy was detected, but in fact it was not).

Laboratory diagnosis of allergy is indispensable in the following situations: 

• active skin lesions (eczema, atopic dermatitis, etc.); 
• increased allergic reaction from the skin, which leads to false-positive or false-negative conclusions (with Quinck edema, mastocytosis, etc.); 
• It is impossible to apply the skin testing method as a result of the constant use of anti-allergic drugs; 
• when testing children and elderly people, the results of skin tests may be unreliable due to changes in the reactivity of the skin (varying degrees of reaction to the stimulus); 
• if an anaphylactic reaction or its prognostic states were previously noted.

The advantages of diagnosing allergies in the laboratory include: 

• safety as a result of the absence of contact of the allergen with the patient; 
• conducting research at any stage of the disease; 
• one-time blood sampling allows you to test the sensitivity to a large number of allergens; 
• Allergy diagnostics results are presented in the form of a quantitative and semi-quantitative indicator, which helps to make a reliable assessment of the degree of sensitivity to the allergen.

[44], [45]

Computer diagnosis of allergies

The computer diagnostics of an allergy by the Foll method has become widespread.

This test collects information about the frequency of electrical oscillations at the cellular level. Nerve endings control the work of the whole organism by means of electrical signals entering the central nervous system. Voll's method is based on fixing data of the information flow.

Results on the state of the body systems are read from electro-puncture points. The technology allows to reliably determine the functional changes and select a suitable drug for each patient through individual testing. The accuracy of diagnosing allergies reaches 99% if it is performed by a qualified doctor.

Science is in constant motion, as a result of which there are devices for the diagnosis of allergies. The Swiss company Phadia developed the ImmunoCap system, which is characterized by high accuracy and quality of results. Among the test kits, there are absolutely unique ones that allow detecting the presence of allergies in children and adults with a certainty of up to 100%. The diagnostic complex includes systems for determining sensitivity to pollen, household dust, mold, as well as methods for detecting cross-reactions.

Japanese quality implies accuracy and reliability. The automatic analyzer "CLA-1 TM Hitachi" is indispensable for carrying out the method of multiple chemiluminescence (MAST). Modern and highly sensitive technology helps reliably identify allergen-specific antibodies in serum. Among the advantages of the device note: reliability, ease of use, the ability to diagnose cross, hidden and polyvalent allergies.

Diagnosis of allergies should include an integrated approach, which begins with consultation with an allergist. The patient should remember all the details of the development of the disease, indicate the alleged factors provocateurs, it is important to talk about similar problems with close relatives. The doctor will ask about the conditions of life, the organization of the workplace, etc. Only after a preliminary conversation, the allergist prescribes a diagnostic method.

[46], [47], [48], [49], [50], [51], [52]