High-frequency ultrasound in the assessment of skin ageing: A systematic review

Background Skin ageing is a complex biological process influenced by intrinsic and extrinsic factors, leading to progressive structural and functional alterations. High-frequency ultrasound (HFUS) has emerged as a non-invasive imaging modality that provides objective and quantitative information on cutaneous morphology. Objectives To systematically review the current evidence on the use of HFUS in the assessment of skin ageing and to summarise its diagnostic relevance and methodological limitations. Methods A systematic review was conducted according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) 2020 guidelines. Three databases (PubMed, Cochrane Library and Embase) were searched up to February 2025 for studies, reviews and meta-analyses employing HFUS to evaluate skin ageing. Twenty-two studies met the inclusion criteria. Results HFUS has been used to analyse the influence of age, sex and ethnicity on skin structure and to identify age-related changes. Consistent findings included a reduction in epidermal thickness and a variable pattern of dermal thickness depending on the anatomical site. Dermal echogenicity tended to decrease in the upper dermis and increase in deeper layers. The subepidermal low-echogenic band (SLEB) was confirmed as a sensitive marker of photoaging, although its interpretation may be influenced by physiological factors. Limitations The included studies were limited by substantial heterogeneity, small sample sizes, predominantly cross-sectional designs, and heterogeneous HFUS protocols, which limit quantitative synthesis. Conclusions HFUS is a valuable, non-invasive and reproducible tool for the objective evaluation of skin ageing. It provides quantitative data on structural skin changes and demonstrates potential clinical utility. Standardised imaging protocols, histologic correlation and longitudinal studies are needed to define consistent diagnostic criteria and assess the efficacy of interventions.