Letter: Cause of acanthosis nigricans

Drug-induced acanthosis nigricans: A systematic review and new classification

Drug-induced acanthosis nigricans is an uncommon subtype of acanthosis nigricans and the data on this topic is not well understood by clinicians as it is presently limited in the literature. Previous reports of drug-induced acanthosis nigricans have simply consisted of a list of drugs possibly implicated in causing acanthosis nigricans. Several drugs listed are based on single case reports without biopsy confirmation, report of clearing on stopping the drug or reporting on whether acanthosis nigricans recurred with drug rechallenge. A comprehensive literature search was conducted using PubMed, EMBASE(Ovid), Cochrane Library, Scopus, and Web of Science electronic databases. The authors screened the initial result of the search strategy by title and abstract using the following inclusion criteria: eligible studies included those with patients who developed acanthosis nigricans secondary to a drug. This study is the first to comprehensively review the drugs that have been implicated in the development of acanthosis nigricans. A total of 38 studies were included in the systematic review, and a total of 13 acanthosis nigricans inducing drugs were identified. Nicotinic acid and insulin were the two most significant drugs that were reported to cause acanthosis nigricans. By using the results of this study, we created a revised classification system of drug-induced acanthosis nigricans which can be used as a concise framework for clinicians to refer to.

Acanthosis nigricans

Acanthosis nigricans is a mucocutaneous eruption that occurs in a strikingly exuberant form as a marker for a highly malignant and rapidly fatal internal cancer. Recently, it has been recognized that acanthosis nigricans may also be a relatively common marker for increased long-term risk of the less dramatic but potentially serious systemic disorders associated with insulin resistance and compensatory increased insulin secretion.

Antibodies against the insulin receptor in paraneoplastic acanthosis nigricans

Acanthosis nigricans is a skin disorder associated with endocrine abnormalities, autoimmune disease, and systemic malignancies. Insulin resistance is a common accompaniment of the nonmalignant varieties of acanthosis nigricans. A 44-year-old man is described with a functioning metastatic pheochromocytoma, acanthosis nigricans, and insulin-resistant diabetes mellitus. Studies of insulin action showed a low titer of anti-insulin antibodies and a very high titer of antibodies against the insulin receptor. This case documents for the first time insulin resistance due to anti-insulin receptor antibodies in a paraneoplastic variety of acanthosis nigricans.

Malignant acanthosis nigricans: a review

Malignant acanthosis nigricans is a dermatosis that appears grossly as a hyperpigmented, velvety, or verrucous hyperplasia of the epidermis, most marked in flexural areas. It is always associated with a malignancy. In 277 cases reviewed, the condition was associated with gastric carcinomas in 55.5%, with other intra-abdominal carcinomas in 17.7%, and with malignancies in other sites in 26.8%. Current theories for the association and pathogenesis of the cutaneous process are discussed.