Lipodystrophy in Insulin-Treated Subjects and Other Injection-Site Skin Reactions: Are We Sure Everything is Clear?

Physicians and patients have long been aware of skin lesions at the sites of insulin injections, referred to as lipodystrophy that can present as lipoatrophy (LA) or lipohypertrophy (LH). However, the reported prevalence of these different skin lesions varies widely, emphasizing the need for a correct identification method. In this short review we discuss LA and LH and also take into account other skin lesions, such as bruising, as well as different needle injuries, including those associated with the subcutaneous injection of pegvisomant (a drug aimed at counteracting the high levels of growth hormone associated with acromegaly), long-acting exenatide (a glucagon-like peptide-1 receptor agonist), and anti-tumor necrosis factor-alpha biologic agents (used against Crohn's disease). In these latter cases specific studies are warranted to understand the pathophysiological background and possible prevention. However, the most common lesion is still insulin injection site-related LD, so a strong effort has to be made to avoid the confusion generated by previously misleading classifications which were barely able to reliably distinguish between LA and LH.