HISTOLOGICAL EVALUATION OF THE EFFECT OF 0.05% TRETINOIN IN THE TREATMENT OF PHOTO DAMAGED SKIN

In a randomised double-blind vehicle controlled trial of 0.05% tretinoin cream in the treatment of photodamaged skin, the histological results of paired biopsies from 28 individuals who applied tretinoin for 26 weeks are compared with 28 paired biopsies from a control group applying vehicle alone. There was a significant increase in epidermal thickness in the tretinoin-treated group (P.001). Epidermal atrophy was reversed in ten patients applying tretinoin cream. Baseline biopsies obtained from participants in Melbourne, Victoria (38° latitude) showed significantly less elastosis than those in Sydney (34° latitude) and Newcastle in N.S.W., although the two groups did not show significant differences in age or sex, and the differences could not be correlated with skin type. Tretinoin cream had no effect on the degree of solar elastosis after 26 weeks application. Tretinoin cream appears effective in reversing epidermal atrophy and clinically diminishes fine wrinkling, mottled hyperpigmentation and skin roughness. Tretinoin cream may not offer a solution to the gross solar damage seen in the Australian population who have marked solar elastosis as a principal, clinical and histologie finding. However it is possible that dermal repair and reversal of solar elastosis may require topical application of tretinoin cream for a longer period than the six months used in this trial.