Assessment of the long-term safety of topical retinoids

Morphologic changes that take place in aging skin or photodamaged skin are the subject of this article. Long-term safety of retinoid use has been established through continued use for more than 30 years and through the clinical trials that were performed to study their histologic effect. Aging skin changes are reviewed and compared with normal skin; and histologic markers, keratinocytes, and melanocytes were followed over time to determine whether retinoids are safe. Based on the histology of skin tissue from patients treated for up to 4 years, topical retinoids were found to be safe and effective in the treatment of topical skin infections.