General Practice 2022

Prick test: what é, what it is for and how é done

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Prick test: what é, what it is for and how é done
Prick test: what é, what it is for and how é done
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The Prick test is a quick allergy test that allows you to identify which type of substances the person is most sensitive to.

To perform the Prick test, substances that can cause allergy are placed on the forearm and, after 15 to 20 minutes, it is observed if any skin reaction has occurred.

Although it is very sensitive and can be performed on people of all ages, the Prick test result is more reliable after 5 years of age, since at this age the immune system is already more developed.

What is it for

The Prick test is indicated to check if the person has any type of food or respiratory allergy.

The main allergies tested are:

  • Shrimp;
  • Milk;
  • Egg;
  • Peanuts;
  • Mites:
  • Dust;
  • Insect bites;
  • Latex.

Most of the time, the Prick test is performed together with the contact allergy test, in which an adhesive tape containing some potentially allergenic substances is placed on the person's back, being removed only after 48 hours. Understand how contact allergy testing is done.

How the test is done

The Prick test is fast, simple, safe and painless. So that this test can be done, it is recommended that the person suspend the use of anti-allergy, in the form of pills, creams or ointments, for about 1 week before the test, so that there is no interference in the result.

Before starting the test, it is important that the forearm is observed in order to identify any sign of dermatitis or lesions, because if these changes are noticed, it may be necessary to perform the test on the other forearm or postpone the performance. of the test. The test is done following the following steps:

  1. Hygiene of the forearm, which is the place where the test is performed, using 70% alcohol;
  2. Application of one drop of each potentially allergenic substance with a minimum distance of 2 centimeters between each one;
  3. Performing a small perforation through the drop in order to bring the substance into direct contact with the organism, leading to an immune reaction. Each perforation is made with a different needle so that there is no contamination and interfere with the final result;
  4. Reaction observation, indicating that the person remains in the environment where the test was performed.

The final results are obtained after 15 to 20 minutes and it is possible that during the wait the person notices the formation of small elevations in the skin, redness and itching, indicating that there was an allergic reaction. Although itching can be quite uncomfortable, it is important that the person does not scratch.

How to understand the results

Results are interpreted by the physician by observing signs on the skin, such as redness or elevations at the site where the test was performed. The tests are considered positive when the red elevation on the skin has a diameter equal to or greater than 3 mm.

It is important that the Prick test results are evaluated by the physician taking into account the person's medical history and the results of other allergy tests.

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