Noninvasive objective skin measurement methods for rosacea assessment: a systematic review

Background Rosacea assessment and therapy monitoring can be challenging to standardize, as most clinical evaluation systems are prone to interobserver variability and not always validated. Therefore, objective, reliable and preferably noninvasive measurement tools are needed. Objectives To give insight into available noninvasive imaging techniques and biophysical methods in rosacea by performing a systematic review. Methods PubMed, Embase, Cochrane and Web of Science databases were searched until 1 September 2018 in accordance with PRISMA guidelines, to identify studies providing original data about objective noninvasive imaging and/or biophysical skin measurement techniques for diagnosis, assessing severity or therapy monitoring of adult patients with cutaneous facial rosacea. Risk of bias of included articles was assessed with the Cochrane Risk of Bias tool, Quality in Prognosis Studies tool, and the Newcastle-Ottawa Scale. Results A total of 78 studies were included, describing 14 imaging and biophysical methods. Widespread information about (sub)surface cutaneous morphology and functionality was obtained. Methodological study quality was relatively low and interstudy outcome variability was large. Several tools show promising value in research settings: for treatment follow-up Demodex mites are countable with reflectance confocal microscopy, spectrometry can quantify erythema, and rosacea severity could be objectified with skin hydration- and transepidermal water loss measurements. Conclusions This systematic review describes the spectrum of noninvasive imaging and biophysical methods in rosacea assessment, giving multifaceted information about structure and properties of rosacea skin, especially useful for research purposes. Larger studies with good methodological quality are needed to create validated protocols for further implementation into research. What's already known about this topic? Rosacea is a chronic inflammatory skin disease with a variety of clinical manifestations. Most clinical evaluation systems are subjective, not always validated, and subsurface skin processes remain unnoticed. Currently, different types of noninvasive measurement tools are available for rosacea assessment and therapy monitoring, but a comprehensive overview is lacking. What does this study add? Seventy-eight publications were included, describing 14 imaging and biophysical tools, providing a wide range of information about rosacea skin morphology and functionality. Reflectance confocal microscopy and spectrometry are especially promising in therapy monitoring and skin barrier measurements for rosacea severity assessment. Larger studies with better methodological quality are needed to create validated protocols for implementation into research.