Prevention and repair of photoaging: sunscreens and retinoids.

The term photoaging describes the gross and microscopic cutaneous alterations that are a consequence of chronic overexposure to sunlight. These changes include severe damage to the dermal connective tissue matrix and are quite different from those associated with innate chronological aging. Long believed to be irreversibly damaged, photoaged skin has now been shown to undergo significant repair when ultraviolet exposures are stopped. With the hairless mouse as a model, we found that sunscreens could prevent photoaging and also allow natural repair to occur. We also found that topical retinoic acid augmented the repair process.