Provocation tests are designed to check the body's response to various external factors, such as allergens, chemicals, low temperature or exercise. The method can be used in the diagnosis of allergies. This type of examination must be strictly supervised by an allergist due to the risk of an anaphylactic reaction. What are provocation tests? How to prepare for the examination?

Contents:

  1. Provocation tests - indications
  2. Provocation tests - contraindications
  3. Food challenge test run
  4. Course of intranasal provocation tests
  5. Course of conjunctival provocation tests
  6. Provocation tests - preparation for tests
  7. Provocative testing - complications

Provocation testsinvolve introducing a small amount of a substance into the patient's body, potentially causing disease symptoms. Such tests are sometimes used in the diagnosis of allergies, but they are not the basic methods of first choice. In the course of allergic provocation tests, the patient is exposed to a sensitizing agent. This is to assess the local or general body reaction related to the potential allergen.

Due to the place of application of the substance, the following samples are distinguished:

  • intranasal,
  • conjunctival,
  • food,
  • bronchial.

Provocation tests - indications

Provocation tests are performed to find the factor that causes the symptoms of the disease in a patient. These types of tests are carried out in the diagnosis of asthma, when the clinical picture is ambiguous.

Provocation trials are also used in determining the effectiveness of pharmacotherapy and immunotherapy. It is also common to carry out this type of tests in the diagnosis of allergies related to occupational risk.

Provocation tests - contraindications

Exposure to an allergen during provocation tests may lead to an exacerbation of the patient's medical condition. The most dangerous possible consequence of the study is anaphylactic shock, which is potentially life-threatening.

Therefore, provocation tests should not becarried out in the case of people with a high risk of he alth deterioration after contact with an allergenic substance.

In addition, provocation attempts are contraindicated in patients who:

  • have had a severe anaphylactic reaction in the past,
  • show acute disease symptoms,
  • are infected,
  • are pregnant.

Food challenge test run

Food provocation tests are usually performed when hypersensitivity to a food component is suspected. In such situations, the patient should follow an elimination diet for 10-14 days prior to the trial.

They are then given food that has the potential to cause an adverse reaction. In some cases, your he althcare professional may recommend a gastrointestinal provocation test in a hospital setting.

As part of the feeding test, you can also perform a lip test. It involves administering a potential allergen under the tongue or into the mouth. After approx. 1 minute, the patient must spit out the sample.

Then the specialist assesses the local reactions after contact with the substance. If we are dealing with an allergen, lip swelling, burning or itching may occur.

Course of intranasal provocation tests

The nasal challenge test evaluates the reaction of the nasal mucosa to contact with an allergen. The test is usually used in addition to data obtained after skin tests or IgE antibody determination. The test results are important in the diagnosis of occupational allergies. Treatment effectiveness can also be monitored by nasal provocation tests.

The provocation test is performed only under the supervision of a specialist doctor. This is important because of the risk of side effects.

The test shall start with a control sample using an inert substance. The nasal reaction is determined after 15 minutes. Then the actual test is carried out, during which a potential allergen is applied to the mucosa.

After 15-30 minutes the doctor re-evaluates the condition of the nose. The patient's self-assessment, based on the frequency of sneezes, the intensity of itching, and the amount of discharge, is also important for diagnosis.

Course of intranasal provocation tests

During the conjunctival provocation test, a potential allergen is injected into the conjunctival sac of one eye of the patient. After the specified time has elapsed, the specialist evaluates reactions such as tearing, itching, and swelling. The described symptoms are compared with those occurring inwithin the unprovoked eye.

Course of conjunctival provocation tests

In the course of bronchial provocation tests, substances potentially causing bronchospasm are administered by inhalation. Reactions are assessed by spirometry.

The test determines the bronchial hyperresponsiveness, which is a characteristic feature of asthma. Sometimes a stress test is also performed.

Provocation tests - preparation for tests

Certain medications must be discontinued to perform provocation tests. This is especially true of antiallergic substances, steroids and some antidepressants. Recommendations for a break in drug therapy may vary. Therefore, follow the information provided by your specialist doctor.

Provocative testing - complications

As a consequence of the provocation test, an exacerbation of the allergic disease may occur. While violent adverse reactions during the test are very rare, they can be dangerous to the patient. The most serious possible complication is anaphylactic shock. It poses a threat to the he alth and life of the respondent.

In order to minimize the side effects associated with the test, a thorough classification is carried out before the test is performed to assess the risk for the patient. For safety reasons, provocative trials should only take place in medical facilities specializing in allergies.

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  • Allergen-specific IgE in allergy diagnosis
About the authorSara Janowska, MA in pharmacyPhD student of interdisciplinary doctoral studies in the field of pharmaceutical and biomedical sciences at the Medical University of Lublin and the Institute of Biotechnology in Białystok. A graduate of pharmaceutical studies at the Medical University of Lublin with a specialization in Plant Medicine. She obtained a master's degree defending a thesis in the field of pharmaceutical botany on the antioxidant properties of extracts obtained from twenty species of mosses. Currently, in his research work, he deals with the synthesis of new anti-cancer substances and the study of their properties on cancer cell lines. For two years she worked as a master of pharmacy in an open pharmacy.

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Category:

Allergies