Acanthosis nigricans and insulin resistance associated with hypothyroidism.

An obese 15-year-old boy with a one-year history of acanthosis nigricans was found to have primary hypothyroidism, with a thyrotropin level in excess of 50 microU/mL. At the same time, he was found to have subclinical insulin resistance. Therapy with thyroxine resulted in weight loss, reversal of hyperinsulinemia, and resolution of the acanthosis nigricans. Hypothyroidism can be added to the list of endocrine diseases associated with acanthosis nigricans. This is unlikely to be a direct effect of the hypothyroid state, but may instead be an indirect action mediated through obesity and subsequent insulin resistance. Insulin resistance and hyperinsulinemia seem to be commonly associated with (and perhaps causative of) the acanthosis nigricans that is seen in many endocrine diseases.