The effect of occlusion of the skin with transdermal therapeutic system on Langerhans' cells and the induction of skin irritation.

Sensitization to drugs in transdermal therapeutic systems is a common unwanted event. We investigated whether prolonged occlusion of the skin causes skin irritation, and in this way might play a role in the possible induction of sensitization to drugs from these systems. Occlusion was effected with a placebo transdermal therapeutic system and silver-patch test in a time span ranging from eight hours to seven days in five groups of five volunteers. Skin irritation was judged on clinical aspects, histopathologic and immunofluorescence findings, and changes in the Langerhans' cell systems. The results indicate that occlusion with the systems used in this experiment provokes only slight or no skin irritation.