HISTOLOGICAL REGRESSION OF EPIDERMAL ATYPIA AFTER SEQUENTIAL TOPICAL 5-FLUOROURACIL AND TRETINOIN IN EARLY PHOTODAMAGE OF THE FACE

BACKGROUND: Intense sun exposure in the first decades of life leads to serious actinic damage. Early therapeutic intervention may prevent pr ogression to more advanced solar damage and cutaneous carcinoma. Topic al 5-fluorouracil (5-FU) is commonly used to treat actinic keratoses, during which time reddened 'flares' develop on apparently uninvolved f acial skin after 2 to 3 weeks of daily applications. OBJECTIVE: Our st rategy was to identify young adults who developed an inflammatory reac tion to 5-FU, and then to treat them with topical tretinoin to reverse epidermal dysplasia. METHODS: A group of 16 fair-skinned subjects age d 18-30 years were treated for 3 weeks with 5% 5-FU cream. Of these su bjects, 13 exhibited flares, which on biopsy were found to be actinic keratoses. These persons were then treated for 6 months with topical t retinoin. Another biopsy was obtained next to the original one. The fa ce was then challenged with 5-FU for 2 weeks to determine whether the actinic keratoses had been eradicated. RESULTS: After 6 months of topi cal tretinoin therapy, biopsies revealed complete clearing of subclini cal actinic keratoses. Challenge with 5-FU produced no inflammatory re sponses. CONCLUSION: Topical tretinoin cream used after a 3-week cours e of topical 5-FU appears to cause regression of the histologic signs of occult actinic keratoses in sun-damaged young adults.