Acanthosis nigricans and the metabolic syndrome

Whether AN can be regarded as one of the risk factors for the diagnosis of MetS, like large waist circumference and elevated blood pressure, is unclear. Correlation between AN and degree of hyperglycemia, insulin resistance, impaired glucose tolerance, and dyslipidemia remains to be confirmed. Classification of AN is inconsistent, and assessment of its severity is less studied. Several monogenic diseases are known to present extensive AN of early onset and can act as models for a better understanding of its pathogenesis. Therapeutic options are limited, and results are unsatisfactory. Retinoids seem to be the most effective topical treatment, and insulin sensitizers, represented by metformin to target insulin resistance, are promising, but controlled studies are lacking. Change of lifestyle to diminish the manifestations of MetS is beneficial, but the influence remains unclarified. Spontaneous remission seems more complete in paraneoplastic AN than in the form associated with obesity and insulin resistance.