Standard Patch Test
The objective of the study is to detect primary skin irritation potential and/or existing allergic sensitization to the test substance.
The test substance is applied to the skin of the panelist via an occlusive patch at a suitable concentration. Thus, the contact of the panelist’s skin with the test substance is locally and temporally limited and due to the occlusive conditions intensified so that the absorption of the test substance is amplified. The skin is assessed at 24, 48 and 72 hours.
The occlusion eases the absorption of the suspected topical allergen allowing it to penetrate the stratum corneum to the viable (effector) cells of the skin and thus presenting a local challenge to the immune system.
If the threshold level of sensitivity is reached, a positive reaction could potentially be induced.
A positive reaction to a correctly applied patch provides evidence of primary irritation to the substance tested, but is not necessarily evidence of sensitization.