Prick Test is an allergic test that allows you to identify what type of substances one has the most sensitivity, and check if the person has food or respiratory allergies.
To do the Prick Test, also known as a puncture test, substances that can cause allergies are placed in the forearm and, after 15 to 20 minutes, is observed if there has been any reaction on the skin.
Although it is quite sensitive and can be performed at people of all ages, the result of the Prick Test is more reliable from the age of 5, as at this age the immune system is already more developed.
So that Serve
The prick test is indicated to diagnose the cause of allergies to:
- Shrimp;
- Leite;
- Ovo;
- Peanut;
- Mites:
- Dust;
- Insect bites;
- Latex.
Most of the time, the prick test is performed along with the contact allergies test, where a tape containing some potentially allergenic substances is placed on the back of the person, being removed only after 48 hours. Understand how the contact allergy test is done.
What is the difference between Prick Test and Patch Test?
Both Prick Test and Patch Test are tests to identify allergies, however, they have differences.
Prick test is made by applying substances to the skin, being indicated mainly when the person has respiratory or food allergies.
Patch Test is made using a tape placed under the skin, being mainly indicated for skin allergies such as atopic dermatitis.
How to prepare for the test
To prepare for the prick test, it is recommended:
- Do not use antiallergic, pills, creams or ointments, for about 1 week before the test;
- Stop taking H2 antihistamine remedies such as cimetidine or family, 48 hours before testing;
- Interrupt the use of tricyclic antidepressants for up to 2 weeks before the test, with medical advice.
These medicines may interfere with the prick test result, reducing or altering the skin reaction to the tested substance, and the interruption of its use should be done with medical advice.
Before starting the test, it is important that the forearm is observed in order to identify any sign of dermatitis or injury, because if these changes are perceived, it may be necessary to test the other forearm or postpone the test.
How the test is done
The test is done following the following step by step:
- Hygiene of the forearmwhich is the place where the test is performed, using 70%alcohol;
- Application of a drop of each substance potentially allergenic with a minimum distance of 2 centimeters between each;
- Performing a small drilling Through the drop in order to make the substance direct contact with the body, leading to the immunological reaction. Each drilling is made with a different needle so that there is no contamination and interfere with the end result;
- Reaction Observationbeing indicated that the person remains in the environment in which the test was performed.
Prick test is fast, simple, safe and does not cause pain and the final results are obtained after 15 to 20 minutes.
If the person has any allergy to the tested substance, it is possible to observe the formation of small elevations in the skin, redness and itching, indicative that there was allergic reaction.
Although itching can be quite uncomfortable, it is important that the person does not score.
How to understand the results
Prick test results are interpreted by the doctor by observing signs on the skin, such as redness or elevations where the test was performed.
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 prick test results are evaluated by the doctor taking into account the person’s clinical history and the result of other allergy tests, such as blood IgE levels. See what the IgE exam is for.
Who should not do
Prick test should not be done in people who have severe dermatographism or skin changes where substances such as atopic dermatitis or acute or chronic urticaria will be tested.
Babies, children, pregnant women, the elderly, people with untt controlled asthma, active angina, cardiac arrhythmias or who take beta -blockers, should be evaluated by the doctor before performing the prick test due to the higher risk of adverse reactions.
Prick test should not be done either when the person did not interrupt the use of doctor -oriented remedies before the exam.
Possible risks
Prick test is a considered safe exam, however, some people may have a headache, fainting or vasovagal syncope.
Also read: Vasovagal syncope: what is, symptoms, causes and treatment
tuasaude.com/sincope-vasovagal
Rarely, generalized urticaria, angioedema or anaphylactic reaction may occur. If they are usually light and treated quickly, as the test is done in clinics with medications and equipment for medical emergencies.
Source: www.tuasaude.com