Patch test (medicine)
The patch test or patch test is a provocative test (allergy test), to be determined by the whether a contact allergy is present. Patch testing is the only means to Late allergies ( in which exposure-response, a larger period is ) to detect.
The debugged allergens (eg, nickel, dyes ) are fixed for about 48 hours with a patch on the skin. On these patches a cream with a chemical solution is applied with the allergens in question. Thereafter, the plaster is removed, and it is the first reading. Their results are obtained with a second reading, which takes place after a further 24 hours compared to distinguish allergic reactions from toxic better. If necessary. you have to wait 24 hours even once.
During the time of the test, the skin may not be exposed to water, to prevent leaching of allergens. If the patient is taking medicines that block or reduce the immune response, it can lead to false negative test results. Likewise, make sure that the contact points are not already pre-loaded ( irritated, eczema, etc.), otherwise false positive results can be caused (so-called "angry back" ).