Is Acanthosis Nigricans a Marker for Metabolic Syndrome? A Systematic Review

Certain skin conditions are proven indicators of underlying systemic disease. Specifically, acanthosis nigricans (AN) is commonly associated with type 2 diabetes and insulin resistance. However, AN may also be a marker of metabolic syndrome (MS). MS is linked to several health conditions leading to death. Therefore, early identification of MS is crucial in preventing disease progression. While AN may provide a visual cue for MS risk, its utility as a clinical screening tool remains underexplored. To address this, we conducted a systematic review to evaluate the association between AN and MS.

We systematically searched PubMed, Embase, and Cochrane Review using the term "acanthosis nigricans," identifying 656 articles, including 322 case reports, that reported AN in association with at least one MS criteria, as defined by the American Heart Association. Article quality was determined using the Strength of Recommendation Taxonomy (SORT) grading system.

Across the 656 included articles, the unweighted mean proportion of study participants with AN was 70.8% (standard deviation of 34.9%), reflecting that many studies evaluated broader patient populations in which AN was one of several conditions assessed. Of all MS criteria, insulin resistance showed the highest mean prevalence of AN at 72.6%. Within all articles, 65.9% met more than one MS criterion, with co-occurrence of insulin resistance and increased body mass being the most common combination (25.5%). In a subanalysis of non-case-report studies in which all participants had AN, 67.4% met the full criteria for MS, with increased body mass being the most frequently reported individual criterion (89.7% of cases).

This review provides a better estimate of AN observed in individuals with MS or in those at risk for MS. Integrating dermatologic examination for AN into primary care and preventive health may improve early detection of MS, reduce costs and unnecessary testing, and promote targeted interventions. Educational efforts are needed to increase clinician awareness of the association between AN and MS.