Clinical evaluation of skin aging: a systematic review

Skin aging is a multifaceted process characterized by a gradual decline in various functions, which leads to wrinkles, sagging, and dyspigmentation. Numerous tools, including photonumeric scales, descriptive scales, and quantitative instruments, have been developed to objectively assess the degree of skin aging. Despite the abundance of evaluation metrics, these scales vary substantially in quality and validity. In this systematic review, we searched MEDLINE via PubMed, EMBASE, and Cochrane databases to identify studies that examined and validated these scales. In total, we included 42 publications comprising 47 scales, including 20 for grading lines and wrinkles, 12 for assessing sagging and volume loss, 6 for evaluating texture and quality, and 9 for global assessment. The individual scales had acceptable strength of agreement and most scales achieved at least moderate inter- and intra-rater reliabilities. This study also reviews the instruments used to quantify age-related skin changes. The parameters examined included surface texture, elasticity, sagging, discoloration, structural integrity, and barrier functions.