Tretinoin therapy in photoageing: historical perspective.

Tretinoin was shown in the late 1960s to be useful for the treatment of disorders associated with abnormal epithelial differentiation; however, because of irritation, retinoids were only slowly accepted. In the 1970s, evidence accumulated to show that topical tretinoin could modulate many of the abnormalities in the epidermis and dermis associated with photoageing. It has been shown in hairless mice that tretinoin can reverse dermal elastosis with the formation of new collagen and this has led to clinical trials being carried out in man. Randomized, controlled trials have shown that topical tretinoin is effective in the treatment of photoaged skin.