Cutaneous Markers of Insulin Resistance and Metabolic Syndrome: Diagnostic Value and Implications for Early Intervention - A Narrative Review

Background: Insulin resistance and metabolic syndrome may remain clinically silent, while selected cutaneous findings are visible during routine examination. Their associations with metabolic abnormalities vary, and they are not diagnostic tests. Objective: To summarize evidence linking selected skin findings with insulin resistance and metabolic syndrome and outline a cautious approach to metabolic assessment in dermatology and primary care. Methods: A targeted narrative search of PubMed, Google Scholar and reference lists identified English-language guidelines, reviews, observational studies and relevant case series available through 31 October 2026. Search concepts covered insulin resistance, metabolic syndrome, acanthosis nigricans, acrochordons, xanthomas and related dermatoses. Evidence was synthesized qualitatively. Results: Acanthosis nigricans has the clearest association with hyperinsulinemia and obesity-related metabolic risk, but diagnostic performance varies across populations and study designs. Multiple acrochordons are associated with dysglycemia and metabolic-syndrome components but are nonspecific. Eruptive xanthomas may signal severe hypertriglyceridemia. Hidradenitis suppurativa and psoriasis are associated with cardiometabolic comorbidity, while acne, hirsutism and female-pattern hair loss require consideration of hyperandrogenism and polycystic ovary syndrome. No single skin sign establishes or excludes insulin resistance or metabolic syndrome. Conclusions: Selected skin findings can prompt risk assessment and guideline-based testing, particularly alongside central adiposity or other risk factors. They are clinical cues, not validated stand-alone tests. Prospective studies with standardized definitions are needed.