A Lean Lady With Acanthosis Nigricans and Uncontrolled Diabetes Mellitus.

A 47-year-old Asian Indian woman presented with uncontrolled hyperglycaemia and osmotic symptoms despite multiple oral antidiabetic medications and insulin. She had a history of recurrent oral ulcers, profound weight loss, and intermittent fever for one and a half years before the presentation. She had severe acanthosis nigricans, although her body mass index (BMI) was 14.6 kg/m. Her blood glucose remained uncontrolled despite very large dosages of intravenous insulin (more than 12,000 units daily). Evaluation for possible underlying collagen vascular diseases and malignancies were negative. Her serum insulin levels were high. She tested negative for anti-insulin antibodies but positive for anti-insulin-receptor antibodies. She improved with a pulse dose of intravenous methylprednisolone but relapsed within one month. A second pulse dose was given following which a complete remission of diabetes and regression of acanthosis was observed. Type B insulin resistance, a rare cause of severe insulin resistance, may respond favourably to immunosuppressive therapy with high-dose methylprednisolone.