A Case of Insulin Edema Syndrome Improved by Weekly Insulin

Insulin edema is a rare complication of insulin therapy, typically occurring during treatment initiation or intensification. We report a 55-year-old woman with a longstanding diagnosis of type 2 diabetes (hemoglobin A1c 11.8% [4.3%-6.0%]) with low adherence to insulin therapy due to the rapid onset of peripheral edema and weight gain following insulin injections. Secondary etiologies of edema were ruled out, and she was diagnosed with insulin edema syndrome. Various types of insulin were tried, including an automated insulin delivery, which worsened her edema and weight gain, leading to discontinuation of all insulins. She was later diagnosed with latent autoimmune diabetes in adults. Weekly insulin icodec was introduced, which was well-tolerated by the patient and improved her adherence to therapy and her insulin edema without significant weight gain. Insulin edema is a diagnosis of exclusion, and clinicians should be aware of this clinical entity. The use of third-generation long-acting insulin analog may be helpful in some patients with this syndrome.