Systematic Literature Review: External Skin Examination as an Indicator of Coronary Heart Disease, Diabetes Mellitus, Stroke, and Chronic Liver Disease

Abstract

Objectives: To systematically review the evidence for external skin examination as a diagnostic indicator of internal diseases, specifically coronary heart disease (CHD), diabetes mellitus (DM), stroke, and chronic liver disease (CLD). while acknowledging key methodological limitations related to heterogeneity in study design, diagnostic criteria, and outcome measurement. Methods: A systematic search of PubMed, Scopus, and Web of Science was conducted following PRISMA 2020 guidelines. Peer-reviewed studies evaluating cutaneous manifestations of CHD, DM, stroke, and CLD were included. Exclusion criteria eliminated grey literature, case reports, non-indexed sources, and publications from MDPI, Hindawi, and Frontiers. Quality assessment employed the Newcastle-Ottawa Scale for observational studies. Results: From 1,247 initial records, 87 studies met inclusion criteria. Xanthelasma palpebrarum was significantly associated with elevated LDL cholesterol (SMD 0.587, 95% CI 0.339–0.836, p<0.001) and increased carotid intima-media thickness (SMD 1.848, 95% CI 0.639–3.057, p=0.003). Diabetic dermopathy affected 9–55% of diabetic patients and correlated with microvascular complications. Spider angiomas demonstrated 50% sensitivity and 88% specificity for cirrhosis (pooled OR 3.5 for alcoholism-associated liver disease). Livedo reticularis was associated with cholesterol embolization syndrome and cerebrovascular events. Conclusions: Structured skin examination provides clinically valuable, non-invasive screening for systemic diseases. However, the findings should be interpreted cautiously because methodological heterogeneity limits direct comparison across studies and precludes firm causal inferenceIntegration of cutaneous findings into preventive medicine protocols may facilitate earlier diagnosis, particularly for CHD, DM, and CLD.