Lipohypertrophy and Insulin: An Old Dog That Needs New Tricks

ObjectiveTo review the current status of practical knowledge related to insulin-associated lipohypertrophy (LH) — an accumulation of fatty subcutaneous nodules commonly caused by repeated injections and/or infusions of insulin into the same site.MethodsReview of published literature with additional contributions from leading multidisciplinary experts with the emphasis on clinical aspects including pathophysiology, clinical and economic consequences, diagnosis, prevention and treatment.ResultsLH is the most common dermatologic complication of insulin therapy. Risk factors for the development of lipohypertrophy include repeated delivery of large amounts of insulin into the same location over time, repeated injection trauma to the skin and subcutaneous tissue, and multiple injections using the same needle. Subcutaneous insulin injection in skin areas with lipohypertrophy is associated with reduced pain; however, this problem can interfere with insulin absorption, thereby increasing the likelihood of glucose variability, hypo- and hyperglycemia when a site is changed. Modern visualization technology of the subcutaneous space with ultrasound can demonstrate lipohypertrophy early in the course of its development.ConclusionsThe physiological and psychological consequences of developing insulin lipohypertrophy can be prevented and treated with education focusing on insulin injection techniques.