This is an automatically translated article.
Patch test is one of the widely used testing methods in medicine to help doctors and patients find out the allergen factors that cause contact dermatitis.1. Patch Test method for allergy testing
Patch Test, also known as skin allergy test method, is a method to help test and evaluate the allergic status of the skin to any agent. This method is performed based on the technique of using prepared allergens to apply to healthy skin, each allergen on a different area of skin. After 48 hours or after 96 hours, if the patient shows signs of allergy to that allergen, it is allowed to diagnose the patient with contact allergy to that allergen.
Contact dermatitis is an inflammatory skin reaction that occurs due to the interaction of the skin with external agents. This agent can be a virus, bacteria, dust, pollen or animal dander... To discuss the diagnosis of atopic dermatitis, people divide it into two different types, which are allergies and irritations. .
Allergic contact dermatitis is a slow type of allergy, inflammatory reactions occur only in some people with atopic allergies and these allergens must be through the body's immune response to be new. can cause disease.
Irritant contact dermatitis is the most common clinical condition. It is inflammation that occurs when the body is exposed to antigens that it does not need through the protection of the immune barrier. The agents here are usually solutions containing acids, alkalis or poisonous insects.
Manifestations of allergic contact dermatitis is an abnormal change in the skin when it comes in contact with irritants such as:
A stinging sensation, even a needle-like pain on the skin at the contact area, can be seen dry, hot as if burned. Red skin rash or tiny blisters. In many severe cases, there may be redness of the skin in an area accompanied by edema, swelling, blistering and blistering, inflamed skin with ulcers. In some other cases, there is no redness and swelling, but the skin is dry, peeling in layers, with or without itching, cracking. In cases where the patient is weak, the immune system is not functioning properly, the allergic condition sometimes shows up not only on the skin but can also appear in the respiratory tract and other parts such as coughing, sneezing, itchy throat. ..
Kết quả sau khi sử dụng phương pháp Patch Test đánh giá viêm da dị ứng tiếp xúc
Contact dermatitis can occur with any antigen depending on the location of each person. When the patient himself cannot determine what substance his body has reacted to, the appointment of Patch test will help more accurately diagnose the cause of these inflammatory manifestations.
As mentioned above, Patch Test is a technique that uses prepared allergens to apply to the skin and then monitor the reactions and manifestations of areas of skin exposed to the allergen. After 48 - 96 hours, the results will be compared with the negative control and it will be concluded whether the patient's body is reacting to this allergen or not. Results after the test can be negative or positive depending on the location of each patient.
In essence, the use of Patch Test is to help doctors and patients determine the main cause of the patient's own contact dermatitis.
How to do skin test :
Prepare patches containing allergens for testing, each patch is a different allergen. Apply patches containing the allergen on healthy skin, each patch has a different position, do not overlap. Monitor skin reaction at allergen patch areas. If 48 - 96 hours, in the skin areas, there are signs of formation of a red streak or urticaria, it means that the patient has atopic dermatitis in contact with that allergen. Note, in some cases, the patient has a slow allergic reaction, so it is accurate and avoids omission. After the skin test, if the result is negative, the patient will be asked to return for a test 2 days later. Test again to make sure that the patient is not allergic to the antigen at all.
Trong phương pháp Patch Test, các miếng dán không được chồng lên nhau và được dán ở vị trí da lành
2. Some notes when doing skin test to diagnose contact dermatitis
In order to perform the skin test to be effective and accurate in diagnosis without affecting the patient's health, it is necessary to note a few things as follows:
It is not indicated to do the skin test for pregnant women and pregnant women. breastfeeding women. Skin testing is contraindicated in children. The skin test is only used to diagnose and find allergens that cause allergic contact dermatitis, and cannot be used to test for other types of allergies such as food allergies. Note the distinction between the skin prick test and the skin prick test in the diagnosis of allergies. During the skin test, remind the patient to avoid excessive sweating, sun exposure or UV light sources as these factors can alter the results. testing, or make the patient more allergic to allergens that are applied to the skin. Patch Test is intended to be used to detect antigens that cause contact dermatitis, but it does not help diagnose the cause of atopic dermatitis. After the skin test technique has been completed, the patient is advised to keep the test area dry during the test. The best period is usually 4 days. Especially in cases where allergic reactions occur slowly, monitor closely and may increase the time of test observation to avoid missed diagnosis. Contact dermatitis is a common clinical condition caused by many different agents such as perfumes, cosmetics, dust, animal hair, chemicals, etc. Inflammation occurs inherently due to the disease body. Patients with a history of and a sensitive response to those substances. Therefore, to limit the condition of contact dermatitis, the most optimal method is that the patient himself should avoid contact with allergens that cause irritation to his body. The difficulty here is that many cases do not know what substance they are allergic to. At that time, the Patch Test is an optimal choice to help the patient and the treating doctor discover the cause of the inflammation, so that the most appropriate treatment can be given.
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