Oral isotretinoin in photoaging: objective histological evidence of efficacy and durability*

BACKGROUND The off-label use of oral isotretinoin in photoaging is a therapeutic tool that has been used by dermatologists. There are few studies to corroborate its effectiveness and durability. OBJECTIVES To assess, both clinically and histologically, the changes caused by the use of oral isotretinoin in skin photoaging as well as the duration of the effects. METHODS 20 female patients, aged 45-50 years, with phototypes II-VI, none of whom had experienced menopause, were treated with 20mg oral isotretinoin, 3 days a week, for 12 weeks. They underwent clinical analysis and skin biopsies in the pre-auricular region, while histologic cuts enabled assessment of the solar elastosis level and morphologic analysis. RESULTS Clinically, patients, as well as the researching and the assessor physicians, noticed improvement in skin quality. One patient presented severe solar elastosis, 11 manifested the moderate form, while 8 presented the discreet type. According to histological analysis, 65% of the patients revealed alteration in the distribution and thickness of the elastic fibers, which can be interpreted as a histological improvement, while 60% showed an increase in collagen density. We observed an increase in collagen density, from 51.2% to 57.4%, (p=0.004). At the end of the 12-week follow-up period, this density decreased to 54.7% (p=0.050). There was an increase in the density of elastic fibers, from 26.5% to 31.3%, (p=0.02), which had dropped to 27.5% at the end of the 12-week follow-up period. CONCLUSIONS The study confirmed the role of oral isotretinoin in remodeling the extracellular matrix against photoaging, as well as its durability after 12 weeks, especially when we consider collagen fibers.