ABSTRACT
Occlusion enhances skin hydration and increases percutaneous absorption of applied substances with few exceptions.1-4 On the other hand, it may also increase penetration of irritants and/or antigens entering into skin and hence may increase irritant and allergic contact dermatitis. In addition, occlusion compromises skin barrier function by impairing passive transepidermal water loss at the application site, and hence aggravates the irritant effect of applied compounds.2, 4-7
Transdermal drug delivery systems (TDDS) are typically occlusive patches placed on the skin surface for 1 to 7 days while delivering drugs into the systemic circulation5 and have been extensively investigated because of potential advantages over traditional oral or other administration route.7-13 However, local reactions (i.e., irritation and/or sensitization) have become obstacles in the design and application of TDDS in clinic situation.7-13 This chapter summarizes the effects on contact dermatitis of occlusion.
