The patch tests (skin contact allergy tests) were first demonstrated by Professor Josef Jadassohn in 1896 as a diagnostic technique for allergic contact dermatitis.
Currently, patch tests are used for Contact Dermatitis (CD) and Atopic Dermatitis (AD) for the diagnosis of a specific contact agent. Patch testing is especially important in case of suspected occupational irritant and allergic CD.
Other indications for testing are: skin irritation after topically applied medications, including cosmetic products, personal care products and other products that are in constant contact with human skin.
The method comprises applying an antigen (allergen) to the skin on a bandage (strips) in standardized concentrations.
You can see on the image below how chemical compound in a reasonable concentration is applied to the hypoallergenic carrier (plaster).
The plaster is applied to a cleansed skin on sensitive area (carpal, popliteal).
The initial evaluation to be made 15 minutes after the application. Skin is examined 15 minutes after the patch test removal.
Next evaluation to be made 24 hours after the application, then in 3 or 4 days, and in some cases – after 7 days.
|Test results evaluation:|
|1 point||the product has a high safety level|
|2 points||the product is considered safe|
|3 and 4 points||the product has not passed the test and is unsafe for use|
|These tests are conducted on 20-50 volunteers for determination of cumulative toxicity factor|