Skin Blood Flowmotion in Various Disease States: A Scoping Review.

Skin blood flowmotion (FM) describes the spontaneous rhythmic changes in microvascular blood flow that occur as blood vessels dilate and constrict over time. These oscillations could occur secondary to several physiological influences, and their frequencies are often expressed as distinct frequency bands associated with cardiac activity, respiration, myogenic tone, neurogenic input, and endothelial factors. Laser Doppler flowmetry (LDF) is commonly used to measure these patterns and to analyze their frequency components. This scoping review examines peer-reviewed English-language studies on FM to better understand its physiological basis and potential relevance across various disease states. A systematic search of Embase, OVID, and Web of Science identified 445 unique articles that used LDF to evaluate FM in relation to a disease state. After screening titles and abstracts of English-language articles involving human subjects, relevant full texts were independently reviewed by two investigators, with a third reviewer resolving disagreements. Studies that focused only on healthy subjects or did not measure FM were excluded. The 41 studies that were included in the review identified several frequency bands in LDF recordings that reflect distinct regulatory mechanisms across disease states. Findings also show that factors such as sympathetic nerve activity, endothelial function, the anatomical site of measurement, and underlying disease can alter these FM oscillatory patterns and may be useful for early disease recognition. The literature also indicates that FM reflects multiple layers of microvascular regulation and may provide useful insights into early or subtle microcirculatory changes. Extended research is warranted that uses more standardized measurement approaches to further clarify clinical significance.